Stop on decoder frame push error

On push, frame sinks report downstream errors to stop upstream
components. Do not ignore the error.

BUILD.md

@@ -15,7 +15,7 @@ First, you need to install the required packages:
 sudo apt install ffmpeg libsdl2-2.0-0 adb wget \
                  gcc git pkg-config meson ninja-build libsdl2-dev \
                  libavcodec-dev libavdevice-dev libavformat-dev libavutil-dev \
-                 libusb-1.0-0 libusb-1.0-0-dev
+                 libswresample-dev libusb-1.0-0 libusb-1.0-0-dev
 ```
 
 Then clone the repo and execute the installation script
@@ -94,7 +94,7 @@ sudo apt install ffmpeg libsdl2-2.0-0 adb libusb-1.0-0
 # client build dependencies
 sudo apt install gcc git pkg-config meson ninja-build libsdl2-dev \
                  libavcodec-dev libavdevice-dev libavformat-dev libavutil-dev \
-                 libusb-1.0-0-dev
+                 libswresample-dev libusb-1.0-0-dev
 
 # server build dependencies
 sudo apt install openjdk-11-jdk

app/meson.build

@@ -11,6 +11,7 @@ src = [
     'src/control_msg.c',
     'src/controller.c',
     'src/decoder.c',
+    'src/delay_buffer.c',
     'src/demuxer.c',
     'src/device_msg.c',
     'src/icon.c',
@@ -29,7 +30,8 @@ src = [
     'src/screen.c',
     'src/server.c',
     'src/version.c',
-    'src/video_buffer.c',
+    'src/trait/frame_source.c',
+    'src/trait/packet_source.c',
     'src/util/acksync.c',
     'src/util/average.c',
     'src/util/bytebuf.c',
@@ -37,6 +39,7 @@ src = [
     'src/util/intmap.c',
     'src/util/intr.c',
     'src/util/log.c',
+    'src/util/memory.c',
     'src/util/net.c',
     'src/util/net_intr.c',
     'src/util/process.c',
@@ -180,6 +183,7 @@ check_functions = [
     'vasprintf',
     'nrand48',
     'jrand48',
+    'reallocarray',
 ]
 
 foreach f : check_functions
@@ -270,9 +274,6 @@ if get_option('buildtype') == 'debug'
             'tests/test_bytebuf.c',
             'src/util/bytebuf.c',
         ]],
-        ['test_cbuf', [
-            'tests/test_cbuf.c',
-        ]],
         ['test_cli', [
             'tests/test_cli.c',
             'src/cli.c',
@@ -297,9 +298,6 @@ if get_option('buildtype') == 'debug'
             'tests/test_device_msg_deserialize.c',
             'src/device_msg.c',
         ]],
-        ['test_queue', [
-            'tests/test_queue.c',
-        ]],
         ['test_strbuf', [
             'tests/test_strbuf.c',
             'src/util/strbuf.c',
@@ -309,6 +307,10 @@ if get_option('buildtype') == 'debug'
             'src/util/str.c',
             'src/util/strbuf.c',
         ]],
+        ['test_vecdeque', [
+            'tests/test_vecdeque.c',
+            'src/util/memory.c',
+        ]],
         ['test_vector', [
             'tests/test_vector.c',
         ]],

app/scrcpy.1

@@ -25,6 +25,12 @@ Encode the audio at the given bit\-rate, expressed in bits/s. Unit suffixes are
 
 Default is 196K (196000).
 
+.TP
+.BI "\-\-audio\-buffer ms
+Add a buffering delay (in milliseconds) before playing audio. This increases latency to compensate for jitter.
+
+Default is 0 (no buffering).
+
 .TP
 .BI "\-\-audio\-codec " name
 Select an audio codec (opus or aac).
@@ -262,6 +268,10 @@ Supported names are currently "direct3d", "opengl", "opengles2", "opengles", "me
 .UR https://wiki.libsdl.org/SDL_HINT_RENDER_DRIVER
 .UE
 
+.TP
+.B \-\-require\-audio
+By default, scrcpy mirrors only the video if audio capture fails on the device. This flag makes scrcpy fail if audio is enabled but does not work.
+
 .TP
 .BI "\-\-rotation " value
 Set the initial display rotation. Possibles values are 0, 1, 2 and 3. Each increment adds a 90 degrees rotation counterclockwise.

app/src/audio_player.c

@@ -4,7 +4,7 @@
 
 #include "util/log.h"
 
-#define SC_AUDIO_PLAYER_NDEBUG // comment to debug
+//#define SC_AUDIO_PLAYER_NDEBUG // comment to debug
 
 /** Downcast frame_sink to sc_audio_player */
 #define DOWNCAST(SINK) container_of(SINK, struct sc_audio_player, frame_sink)
@@ -18,14 +18,22 @@
 // This value is directly use for compensation.
 #define SC_TARGET_BUFFERED_SAMPLES (3 * SC_AUDIO_OUTPUT_BUFFER_SAMPLES)
 
-// If the consumer is too late, skip samples to keep at most this value
-#define SC_BUFFERED_SAMPLES_THRESHOLD 2400 // 50ms at 48000Hz
-
 // Use a ring-buffer of 1 second (at 48000Hz) between the producer and the
 // consumer. It too big, but it guarantees that the producer and the consumer
 // will be able to access it in parallel without locking.
 #define SC_BYTEBUF_SIZE_IN_SAMPLES 48000
 
+static inline size_t
+bytes_to_samples(struct sc_audio_player *ap, size_t bytes) {
+    assert(bytes % (ap->nb_channels * ap->out_bytes_per_sample) == 0);
+    return bytes / (ap->nb_channels * ap->out_bytes_per_sample);
+}
+
+static inline size_t
+samples_to_bytes(struct sc_audio_player *ap, size_t samples) {
+    return samples * ap->nb_channels * ap->out_bytes_per_sample;
+}
+
 void
 sc_audio_player_sdl_callback(void *userdata, uint8_t *stream, int len_int) {
     struct sc_audio_player *ap = userdata;
@@ -38,32 +46,12 @@ sc_audio_player_sdl_callback(void *userdata, uint8_t *stream, int len_int) {
 
 #ifndef SC_AUDIO_PLAYER_NDEBUG
     LOGD("[Audio] SDL callback requests %" SC_PRIsizet " samples",
-         len / (ap->nb_channels * ap->out_bytes_per_sample));
+         bytes_to_samples(ap, len));
 #endif
 
-    size_t read = sc_bytebuf_read_remaining(&ap->buf);
-    size_t max_buffered_bytes = SC_BUFFERED_SAMPLES_THRESHOLD
-                              * ap->nb_channels * ap->out_bytes_per_sample;
-    if (read > max_buffered_bytes + len) {
-        size_t skip = read - (max_buffered_bytes + len);
-#ifndef SC_AUDIO_PLAYER_NDEBUG
-        LOGD("[Audio] Buffered samples threshold exceeded: %" SC_PRIsizet
-             " bytes, skipping %" SC_PRIsizet " bytes", read, skip);
-#endif
-        // After this callback, exactly max_buffered_bytes will remain
-        sc_bytebuf_skip(&ap->buf, skip);
-        read = max_buffered_bytes + len;
-    }
-
-    // Number of buffered samples (may be negative on underflow)
-    float buffered_samples = ((float) read - len_int)
-                           / (ap->nb_channels * ap->out_bytes_per_sample);
-    sc_average_push(&ap->avg_buffered_samples, buffered_samples);
-
+    size_t read_avail = sc_bytebuf_read_available(&ap->buf);
+    size_t read = MIN(read_avail, len);
     if (read) {
-        if (read > len) {
-            read = len;
-        }
         sc_bytebuf_read(&ap->buf, stream, read);
     }
 
@@ -71,22 +59,18 @@ sc_audio_player_sdl_callback(void *userdata, uint8_t *stream, int len_int) {
         // Insert silence
 #ifndef SC_AUDIO_PLAYER_NDEBUG
         LOGD("[Audio] Buffer underflow, inserting silence: %" SC_PRIsizet
-             " bytes", len - read);
+             " samples", bytes_to_samples(ap, len - read));
 #endif
         memset(stream + read, 0, len - read);
+        ap->underflow += bytes_to_samples(ap, len - read);
     }
-}
 
-static size_t
-sc_audio_player_get_buf_size(struct sc_audio_player *ap, size_t samples) {
-    assert(ap->nb_channels);
-    assert(ap->out_bytes_per_sample);
-    return samples * ap->nb_channels * ap->out_bytes_per_sample;
+    ap->last_consumed = sc_tick_now();
 }
 
 static uint8_t *
 sc_audio_player_get_swr_buf(struct sc_audio_player *ap, size_t min_samples) {
-    size_t min_buf_size = sc_audio_player_get_buf_size(ap, min_samples);
+    size_t min_buf_size = samples_to_bytes(ap, min_samples);
     if (min_buf_size < ap->swr_buf_alloc_size) {
         size_t new_size = min_buf_size + 4096;
         uint8_t *buf = realloc(ap->swr_buf, new_size);
@@ -170,17 +154,14 @@ sc_audio_player_frame_sink_open(struct sc_frame_sink *sink,
     ap->nb_channels = nb_channels;
     ap->out_bytes_per_sample = out_bytes_per_sample;
 
-    size_t bytebuf_size =
-        sc_audio_player_get_buf_size(ap, SC_BYTEBUF_SIZE_IN_SAMPLES);
+    size_t bytebuf_size = samples_to_bytes(ap, SC_BYTEBUF_SIZE_IN_SAMPLES);
 
     bool ok = sc_bytebuf_init(&ap->buf, bytebuf_size);
     if (!ok) {
         goto error_free_swr_ctx;
     }
 
-    ap->safe_empty_buffer = sc_bytebuf_write_remaining(&ap->buf);
-
-    size_t initial_swr_buf_size = sc_audio_player_get_buf_size(ap, 4096);
+    size_t initial_swr_buf_size = samples_to_bytes(ap, 4096);
     ap->swr_buf = malloc(initial_swr_buf_size);
     if (!ap->swr_buf) {
         LOG_OOM();
@@ -188,9 +169,14 @@ sc_audio_player_frame_sink_open(struct sc_frame_sink *sink,
     }
     ap->swr_buf_alloc_size = initial_swr_buf_size;
 
-    sc_average_init(&ap->avg_buffered_samples, 32);
+    ap->previous_write_avail = sc_bytebuf_write_available(&ap->buf);
+
+    sc_average_init(&ap->avg_buffering, 8);
     ap->samples_since_resync = 0;
 
+    ap->last_consumed = 0;
+    ap->underflow = 0;
+
     SDL_PauseAudioDevice(ap->device, 0);
 
     return true;
@@ -219,16 +205,18 @@ sc_audio_player_frame_sink_close(struct sc_frame_sink *sink) {
 }
 
 static bool
-sc_audio_player_frame_sink_push(struct sc_frame_sink *sink, const AVFrame *frame) {
+sc_audio_player_frame_sink_push(struct sc_frame_sink *sink,
+                                const AVFrame *frame) {
     struct sc_audio_player *ap = DOWNCAST(sink);
 
     SwrContext *swr_ctx = ap->swr_ctx;
 
     int64_t delay = swr_get_delay(swr_ctx, ap->sample_rate);
     // No need to av_rescale_rnd(), input and output sample rates are the same
-    int dst_nb_samples = delay + frame->nb_samples;
+    // Add more space (256) for clock compensation
+    int dst_nb_samples = delay + frame->nb_samples + 256;
 
-    uint8_t *swr_buf = sc_audio_player_get_swr_buf(ap, frame->nb_samples);
+    uint8_t *swr_buf = sc_audio_player_get_swr_buf(ap, dst_nb_samples);
     if (!swr_buf) {
         return false;
     }
@@ -240,52 +228,130 @@ sc_audio_player_frame_sink_push(struct sc_frame_sink *sink, const AVFrame *frame
         return false;
     }
 
-    size_t samples_written = ret;
-    size_t swr_buf_size = sc_audio_player_get_buf_size(ap, samples_written);
+    // swr_convert() returns the number of samples which would have been
+    // written if the buffer was big enough.
+    size_t samples_written = MIN(ret, dst_nb_samples);
+    size_t swr_buf_size = samples_to_bytes(ap, samples_written);
 #ifndef SC_AUDIO_PLAYER_NDEBUG
     LOGI("[Audio] %" SC_PRIsizet " samples written to buffer", samples_written);
 #endif
 
-    // It should almost always be possible to write without lock
-    bool can_write_without_lock = swr_buf_size <= ap->safe_empty_buffer;
-    if (can_write_without_lock) {
+    // Since this function is the only writer, the current available space is
+    // at least the previous available space. In practice, it should almost
+    // always be possible to write without lock.
+    bool lockless_write = swr_buf_size <= ap->previous_write_avail;
+    if (lockless_write) {
         sc_bytebuf_prepare_write(&ap->buf, swr_buf, swr_buf_size);
     }
 
     SDL_LockAudioDevice(ap->device);
-    if (can_write_without_lock) {
+
+    // The consumer requests audio samples blocks (e.g. 480 samples).
+    // Convert the duration since the last consumption into samples.
+    size_t extrapolated = 0;
+    if (ap->last_consumed) {
+        sc_tick now = sc_tick_now();
+        assert(now >= ap->last_consumed);
+        extrapolated = (sc_tick_now() - ap->last_consumed) * ap->sample_rate
+                                                           / SC_TICK_FREQ;
+    }
+
+    size_t read_avail = sc_bytebuf_read_available(&ap->buf);
+
+    // The consumer may not increase underflow value if there are still samples
+    // available
+    assert(read_avail == 0 || ap->underflow == 0);
+
+    size_t buffered_samples = bytes_to_samples(ap, read_avail);
+    // Underflow caused silence samples in excess (so it adds buffering).
+    // Extrapolated samples must be considered consumed for smoothing (so it
+    // removes buffering).
+    float buffering = (float) buffered_samples + ap->underflow - extrapolated;
+    sc_average_push(&ap->avg_buffering, buffering);
+
+#ifndef SC_AUDIO_PLAYER_NDEBUG
+    LOGD("[AUDIO] buffered_samples=%" SC_PRIsizet
+                " underflow=%" SC_PRIsizet
+                " extrapolated=%" SC_PRIsizet
+                " buffering=%f avg_buffering=%f",
+         buffered_samples, ap->underflow, extrapolated, buffering,
+         sc_average_get(&ap->avg_buffering));
+#endif
+
+    if (lockless_write) {
         sc_bytebuf_commit_write(&ap->buf, swr_buf_size);
     } else {
+        // Take care to keep full samples
+        size_t align = ap->nb_channels * ap->out_bytes_per_sample;
+        size_t write_avail =
+            sc_bytebuf_write_available(&ap->buf) / align * align;
+        if (swr_buf_size > write_avail) {
+            // Skip old samples
+            size_t cap = sc_bytebuf_capacity(&ap->buf) / align * align;
+            if (swr_buf_size > cap) {
+                // Ignore the first bytes in swr_buf
+                swr_buf += swr_buf_size - cap;
+                swr_buf_size = cap;
+            }
+            assert(swr_buf_size > write_avail);
+            if (swr_buf_size - write_avail > 0) {
+                sc_bytebuf_skip(&ap->buf, swr_buf_size - write_avail);
+            }
+        }
         sc_bytebuf_write(&ap->buf, swr_buf, swr_buf_size);
     }
 
-    // The next time, it will remain at least the current empty space
-    ap->safe_empty_buffer = sc_bytebuf_write_remaining(&ap->buf);
+    // On buffer underflow, typically because a packet is late, silence is
+    // inserted. In that case, the late samples must be ignored when they
+    // arrive, otherwise they will delay playback.
+    //
+    // As an improvement, instead of naively skipping the silence duration, we
+    // can absorb it if it helps clock compensation.
+    if (ap->underflow) {
+        size_t avg = sc_average_get(&ap->avg_buffering);
+        if (avg > SC_TARGET_BUFFERED_SAMPLES) {
+            size_t diff = SC_TARGET_BUFFERED_SAMPLES - avg;
+            if (diff < ap->underflow) {
+                // Partially absorb underflow for clock compensation (only keep
+                // the diff with the target buffering level).
+                ap->underflow = diff;
+            }
 
-    // Read the value written by the SDL thread under lock
-    float avg;
-    bool has_avg = sc_average_get(&ap->avg_buffered_samples, &avg);
+            size_t skip_samples = MIN(ap->underflow, buffered_samples);
+            if (skip_samples) {
+                size_t skip_bytes = samples_to_bytes(ap, skip_samples);
+                sc_bytebuf_skip(&ap->buf, skip_bytes);
+                read_avail -= skip_bytes;
+#ifndef SC_AUDIO_PLAYER_NDEBUG
+                LOGD("[Audio] Skipping %" SC_PRIsizet " samples", skip_samples);
+#endif
+            }
+        } else {
+            // Totally absorb underflow for clock compensation
+            ap->underflow = 0;
+        }
+    }
+
+    ap->previous_write_avail = sc_bytebuf_write_available(&ap->buf);
 
     SDL_UnlockAudioDevice(ap->device);
 
-    if (has_avg) {
-        ap->samples_since_resync += samples_written;
-        if (ap->samples_since_resync >= ap->sample_rate) {
-            // Resync every second
-            ap->samples_since_resync = 0;
+    ap->samples_since_resync += samples_written;
+    if (ap->samples_since_resync >= ap->sample_rate) {
+        // Resync every second
+        ap->samples_since_resync = 0;
 
-            int diff = SC_TARGET_BUFFERED_SAMPLES - avg;
+        float avg = sc_average_get(&ap->avg_buffering);
+        int diff = SC_TARGET_BUFFERED_SAMPLES - avg;
 #ifndef SC_AUDIO_PLAYER_NDEBUG
-            LOGI("[Audio] Average buffered samples = %f, compensation %d",
-                 avg, diff);
+        LOGI("[Audio] Average buffering=%f, compensation %d", avg, diff);
 #endif
-            // Compensate the diff over 3 seconds (but will be recomputed after
-            // 1 second)
-            int ret = swr_set_compensation(swr_ctx, diff, 3 * ap->sample_rate);
-            if (ret < 0) {
-                LOGW("Resampling compensation failed: %d", ret);
-                // not fatal
-            }
+        // Compensate the diff over 3 seconds (but will be recomputed after
+        // 1 second)
+        int ret = swr_set_compensation(swr_ctx, diff, 3 * ap->sample_rate);
+        if (ret < 0) {
+            LOGW("Resampling compensation failed: %d", ret);
+            // not fatal
         }
     }
 

app/src/audio_player.h

@@ -20,8 +20,7 @@ struct sc_audio_player {
 
     // protected by SDL_AudioDeviceLock()
     struct sc_bytebuf buf;
-    // Number of bytes which could be written without locking
-    size_t safe_empty_buffer;
+    size_t previous_write_avail;
 
     struct SwrContext *swr_ctx;
 
@@ -29,7 +28,7 @@ struct sc_audio_player {
     unsigned sample_rate;
     // The number of channels is the same for input and output
     unsigned nb_channels;
-
+    // The number of bytes per sample for a single channel
     unsigned out_bytes_per_sample;
 
     // Target buffer for resampling
@@ -37,8 +36,15 @@ struct sc_audio_player {
     size_t swr_buf_alloc_size;
 
     // Number of buffered samples (may be negative on underflow)
-    struct sc_average avg_buffered_samples;
-    unsigned samples_since_resync;
+    struct sc_average avg_buffering;
+    // Count the number of samples to trigger a compensation update regularly
+    size_t samples_since_resync;
+
+    // The last date a sample has been consumed by the audio output
+    sc_tick last_consumed;
+
+    // Number of silence samples inserted to be compensated
+    size_t underflow;
 
     const struct sc_audio_player_callbacks *cbs;
     void *cbs_userdata;

app/src/cli.c

@@ -69,6 +69,8 @@ enum {
     OPT_AUDIO_ENCODER,
     OPT_LIST_ENCODERS,
     OPT_LIST_DISPLAYS,
+    OPT_REQUIRE_AUDIO,
+    OPT_AUDIO_BUFFER,
 };
 
 struct sc_option {
@@ -118,6 +120,14 @@ static const struct sc_option options[] = {
                 "Unit suffixes are supported: 'K' (x1000) and 'M' (x1000000).\n"
                 "Default is 196K (196000).",
     },
+    {
+        .longopt_id = OPT_AUDIO_BUFFER,
+        .longopt = "audio-buffer",
+        .argdesc = "ms",
+        .text = "Add a buffering delay (in milliseconds) before playing audio. "
+                "This increases latency to compensate for jitter.\n"
+                "Default is 0 (no buffering).",
+    },
     {
         .longopt_id = OPT_AUDIO_CODEC,
         .longopt = "audio-codec",
@@ -458,6 +468,13 @@ static const struct sc_option options[] = {
         .longopt_id = OPT_RENDER_EXPIRED_FRAMES,
         .longopt = "render-expired-frames",
     },
+    {
+        .longopt_id = OPT_REQUIRE_AUDIO,
+        .longopt = "require-audio",
+        .text = "By default, scrcpy mirrors only the video when audio capture "
+                "fails on the device. This flag makes scrcpy fail if audio is "
+                "enabled but does not work."
+    },
     {
         .longopt_id = OPT_ROTATION,
         .longopt = "rotation",
@@ -1801,6 +1818,14 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
             case OPT_LIST_DISPLAYS:
                 opts->list_displays = true;
                 break;
+            case OPT_REQUIRE_AUDIO:
+                opts->require_audio = true;
+                break;
+            case OPT_AUDIO_BUFFER:
+                if (!parse_buffering_time(optarg, &opts->audio_buffer)) {
+                    return false;
+                }
+                break;
             default:
                 // getopt prints the error message on stderr
                 return false;
@@ -1861,6 +1886,11 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
     }
 #endif
 
+    if (opts->audio && !opts->display && !opts->record_filename) {
+        LOGI("No display and no recording: audio disabled");
+        opts->audio = false;
+    }
+
     if ((opts->tunnel_host || opts->tunnel_port) && !opts->force_adb_forward) {
         LOGI("Tunnel host/port is set, "
              "--force-adb-forward automatically enabled.");

app/src/clock.c

@@ -18,7 +18,15 @@ sc_clock_init(struct sc_clock *clock) {
 static void
 sc_clock_estimate(struct sc_clock *clock,
                   double *out_slope, sc_tick *out_offset) {
-    assert(clock->count > 1); // two points are necessary
+    assert(clock->count);
+
+    if (clock->count == 1) {
+        // If there is only 1 point, we can't compute a slope. Assume it is 1.
+        struct sc_clock_point *single_point = &clock->right_sum;
+        *out_slope = 1;
+        *out_offset = single_point->system - single_point->stream;
+        return;
+    }
 
     struct sc_clock_point left_avg = {
         .system = clock->left_sum.system / (clock->count / 2),
@@ -93,19 +101,17 @@ sc_clock_update(struct sc_clock *clock, sc_tick system, sc_tick stream) {
 
     clock->head = (clock->head + 1) % SC_CLOCK_RANGE;
 
-    if (clock->count > 1) {
-        // Update estimation
-        sc_clock_estimate(clock, &clock->slope, &clock->offset);
+    // Update estimation
+    sc_clock_estimate(clock, &clock->slope, &clock->offset);
 
 #ifndef SC_CLOCK_NDEBUG
-        LOGD("Clock estimation: %f * pts + %" PRItick,
-             clock->slope, clock->offset);
+    LOGD("Clock estimation: %f * pts + %" PRItick,
+         clock->slope, clock->offset);
 #endif
-    }
 }
 
 sc_tick
 sc_clock_to_system_time(struct sc_clock *clock, sc_tick stream) {
-    assert(clock->count > 1); // sc_clock_update() must have been called
+    assert(clock->count); // sc_clock_update() must have been called
     return (sc_tick) (stream * clock->slope) + clock->offset;
 }

app/src/common.h

@@ -5,8 +5,8 @@
 #include "compat.h"
 
 #define ARRAY_LEN(a) (sizeof(a) / sizeof(a[0]))
-#define MIN(X,Y) (X) < (Y) ? (X) : (Y)
-#define MAX(X,Y) (X) > (Y) ? (X) : (Y)
+#define MIN(X,Y) ((X) < (Y) ? (X) : (Y))
+#define MAX(X,Y) ((X) > (Y) ? (X) : (Y))
 #define CLAMP(V,X,Y) MIN( MAX((V),(X)), (Y) )
 
 #define container_of(ptr, type, member) \

app/src/compat.c

@@ -3,6 +3,9 @@
 #include "config.h"
 
 #include <assert.h>
+#ifndef HAVE_REALLOCARRAY
+# include <errno.h>
+#endif
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdarg.h>
@@ -93,5 +96,15 @@ long jrand48(unsigned short xsubi[3]) {
     return v.i;
 }
 #endif
-
+#endif
+
+#ifndef HAVE_REALLOCARRAY
+void *reallocarray(void *ptr, size_t nmemb, size_t size) {
+    size_t bytes;
+    if (__builtin_mul_overflow(nmemb, size, &bytes)) {
+      errno = ENOMEM;
+      return NULL;
+    }
+    return realloc(ptr, bytes);
+}
 #endif

app/src/compat.h

@@ -74,4 +74,8 @@ long nrand48(unsigned short xsubi[3]);
 long jrand48(unsigned short xsubi[3]);
 #endif
 
+#ifndef HAVE_REALLOCARRAY
+void *reallocarray(void *ptr, size_t nmemb, size_t size);
+#endif
+
 #endif

app/src/controller.c

@@ -4,19 +4,28 @@
 
 #include "util/log.h"
 
+#define SC_CONTROL_MSG_QUEUE_MAX 64
+
 bool
 sc_controller_init(struct sc_controller *controller, sc_socket control_socket,
                    struct sc_acksync *acksync) {
-    cbuf_init(&controller->queue);
+    sc_vecdeque_init(&controller->queue);
 
-    bool ok = sc_receiver_init(&controller->receiver, control_socket, acksync);
+    bool ok = sc_vecdeque_reserve(&controller->queue, SC_CONTROL_MSG_QUEUE_MAX);
     if (!ok) {
         return false;
     }
 
+    ok = sc_receiver_init(&controller->receiver, control_socket, acksync);
+    if (!ok) {
+        sc_vecdeque_destroy(&controller->queue);
+        return false;
+    }
+
     ok = sc_mutex_init(&controller->mutex);
     if (!ok) {
         sc_receiver_destroy(&controller->receiver);
+        sc_vecdeque_destroy(&controller->queue);
         return false;
     }
 
@@ -24,6 +33,7 @@ sc_controller_init(struct sc_controller *controller, sc_socket control_socket,
     if (!ok) {
         sc_receiver_destroy(&controller->receiver);
         sc_mutex_destroy(&controller->mutex);
+        sc_vecdeque_destroy(&controller->queue);
         return false;
     }
 
@@ -38,10 +48,12 @@ sc_controller_destroy(struct sc_controller *controller) {
     sc_cond_destroy(&controller->msg_cond);
     sc_mutex_destroy(&controller->mutex);
 
-    struct sc_control_msg msg;
-    while (cbuf_take(&controller->queue, &msg)) {
-        sc_control_msg_destroy(&msg);
+    while (!sc_vecdeque_is_empty(&controller->queue)) {
+        struct sc_control_msg *msg = sc_vecdeque_popref(&controller->queue);
+        assert(msg);
+        sc_control_msg_destroy(msg);
     }
+    sc_vecdeque_destroy(&controller->queue);
 
     sc_receiver_destroy(&controller->receiver);
 }
@@ -54,13 +66,19 @@ sc_controller_push_msg(struct sc_controller *controller,
     }
 
     sc_mutex_lock(&controller->mutex);
-    bool was_empty = cbuf_is_empty(&controller->queue);
-    bool res = cbuf_push(&controller->queue, *msg);
-    if (was_empty) {
-        sc_cond_signal(&controller->msg_cond);
+    bool full = sc_vecdeque_is_full(&controller->queue);
+    if (!full) {
+        bool was_empty = sc_vecdeque_is_empty(&controller->queue);
+        sc_vecdeque_push_noresize(&controller->queue, *msg);
+        if (was_empty) {
+            sc_cond_signal(&controller->msg_cond);
+        }
     }
+    // Otherwise (if the queue is full), the msg is discarded
+
     sc_mutex_unlock(&controller->mutex);
-    return res;
+
+    return !full;
 }
 
 static bool
@@ -82,7 +100,8 @@ run_controller(void *data) {
 
     for (;;) {
         sc_mutex_lock(&controller->mutex);
-        while (!controller->stopped && cbuf_is_empty(&controller->queue)) {
+        while (!controller->stopped
+                && sc_vecdeque_is_empty(&controller->queue)) {
             sc_cond_wait(&controller->msg_cond, &controller->mutex);
         }
         if (controller->stopped) {
@@ -90,10 +109,9 @@ run_controller(void *data) {
             sc_mutex_unlock(&controller->mutex);
             break;
         }
-        struct sc_control_msg msg;
-        bool non_empty = cbuf_take(&controller->queue, &msg);
-        assert(non_empty);
-        (void) non_empty;
+
+        assert(!sc_vecdeque_is_empty(&controller->queue));
+        struct sc_control_msg msg = sc_vecdeque_pop(&controller->queue);
         sc_mutex_unlock(&controller->mutex);
 
         bool ok = process_msg(controller, &msg);

app/src/controller.h

@@ -8,11 +8,11 @@
 #include "control_msg.h"
 #include "receiver.h"
 #include "util/acksync.h"
-#include "util/cbuf.h"
 #include "util/net.h"
 #include "util/thread.h"
+#include "util/vecdeque.h"
 
-struct sc_control_msg_queue CBUF(struct sc_control_msg, 64);
+struct sc_control_msg_queue SC_VECDEQUE(struct sc_control_msg);
 
 struct sc_controller {
     sc_socket control_socket;

app/src/decoder.c

@@ -5,39 +5,12 @@
 #include <libavutil/channel_layout.h>
 
 #include "events.h"
-#include "video_buffer.h"
 #include "trait/frame_sink.h"
 #include "util/log.h"
 
 /** Downcast packet_sink to decoder */
 #define DOWNCAST(SINK) container_of(SINK, struct sc_decoder, packet_sink)
 
-static void
-sc_decoder_close_first_sinks(struct sc_decoder *decoder, unsigned count) {
-    while (count) {
-        struct sc_frame_sink *sink = decoder->sinks[--count];
-        sink->ops->close(sink);
-    }
-}
-
-static inline void
-sc_decoder_close_sinks(struct sc_decoder *decoder) {
-    sc_decoder_close_first_sinks(decoder, decoder->sink_count);
-}
-
-static bool
-sc_decoder_open_sinks(struct sc_decoder *decoder, const AVCodecContext *ctx) {
-    for (unsigned i = 0; i < decoder->sink_count; ++i) {
-        struct sc_frame_sink *sink = decoder->sinks[i];
-        if (!sink->ops->open(sink, ctx)) {
-            sc_decoder_close_first_sinks(decoder, i);
-            return false;
-        }
-    }
-
-    return true;
-}
-
 static bool
 sc_decoder_open(struct sc_decoder *decoder, const AVCodec *codec) {
     decoder->codec_ctx = avcodec_alloc_context3(codec);
@@ -77,7 +50,8 @@ sc_decoder_open(struct sc_decoder *decoder, const AVCodec *codec) {
         return false;
     }
 
-    if (!sc_decoder_open_sinks(decoder, decoder->codec_ctx)) {
+    if (!sc_frame_source_sinks_open(&decoder->frame_source,
+                                    decoder->codec_ctx)) {
         av_frame_free(&decoder->frame);
         avcodec_close(decoder->codec_ctx);
         avcodec_free_context(&decoder->codec_ctx);
@@ -89,24 +63,12 @@ sc_decoder_open(struct sc_decoder *decoder, const AVCodec *codec) {
 
 static void
 sc_decoder_close(struct sc_decoder *decoder) {
-    sc_decoder_close_sinks(decoder);
+    sc_frame_source_sinks_close(&decoder->frame_source);
     av_frame_free(&decoder->frame);
     avcodec_close(decoder->codec_ctx);
     avcodec_free_context(&decoder->codec_ctx);
 }
 
-static bool
-push_frame_to_sinks(struct sc_decoder *decoder, const AVFrame *frame) {
-    for (unsigned i = 0; i < decoder->sink_count; ++i) {
-        struct sc_frame_sink *sink = decoder->sinks[i];
-        if (!sink->ops->push(sink, frame)) {
-            return false;
-        }
-    }
-
-    return true;
-}
-
 static bool
 sc_decoder_push(struct sc_decoder *decoder, const AVPacket *packet) {
     bool is_config = packet->pts == AV_NOPTS_VALUE;
@@ -121,20 +83,29 @@ sc_decoder_push(struct sc_decoder *decoder, const AVPacket *packet) {
              decoder->name, ret);
         return false;
     }
-    ret = avcodec_receive_frame(decoder->codec_ctx, decoder->frame);
-    if (!ret) {
-        // a frame was received
-        bool ok = push_frame_to_sinks(decoder, decoder->frame);
-        // A frame lost should not make the whole pipeline fail. The error, if
-        // any, is already logged.
-        (void) ok;
 
+    for (;;) {
+        ret = avcodec_receive_frame(decoder->codec_ctx, decoder->frame);
+        if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
+            break;
+        }
+
+        if (ret) {
+            LOGE("Decoder '%s', could not receive video frame: %d",
+                 decoder->name, ret);
+            return false;
+        }
+
+        // a frame was received
+        bool ok = sc_frame_source_sinks_push(&decoder->frame_source,
+                                             decoder->frame);
         av_frame_unref(decoder->frame);
-    } else if (ret != AVERROR(EAGAIN)) {
-        LOGE("Decoder '%s', could not receive video frame: %d",
-             decoder->name, ret);
-        return false;
+        if (!ok) {
+            // Error already logged
+            return false;
+        }
     }
+
     return true;
 }
 
@@ -160,7 +131,7 @@ sc_decoder_packet_sink_push(struct sc_packet_sink *sink,
 void
 sc_decoder_init(struct sc_decoder *decoder, const char *name) {
     decoder->name = name; // statically allocated
-    decoder->sink_count = 0;
+    sc_frame_source_init(&decoder->frame_source);
 
     static const struct sc_packet_sink_ops ops = {
         .open = sc_decoder_packet_sink_open,
@@ -170,11 +141,3 @@ sc_decoder_init(struct sc_decoder *decoder, const char *name) {
 
     decoder->packet_sink.ops = &ops;
 }
-
-void
-sc_decoder_add_sink(struct sc_decoder *decoder, struct sc_frame_sink *sink) {
-    assert(decoder->sink_count < SC_DECODER_MAX_SINKS);
-    assert(sink);
-    assert(sink->ops);
-    decoder->sinks[decoder->sink_count++] = sink;
-}

app/src/decoder.h

@@ -3,22 +3,19 @@
 
 #include "common.h"
 
+#include "trait/frame_source.h"
 #include "trait/packet_sink.h"
 
 #include <stdbool.h>
 #include <libavcodec/avcodec.h>
 #include <libavformat/avformat.h>
 
-#define SC_DECODER_MAX_SINKS 2
-
 struct sc_decoder {
     struct sc_packet_sink packet_sink; // packet sink trait
+    struct sc_frame_source frame_source; // frame source trait
 
     const char *name; // must be statically allocated (e.g. a string literal)
 
-    struct sc_frame_sink *sinks[SC_DECODER_MAX_SINKS];
-    unsigned sink_count;
-
     AVCodecContext *codec_ctx;
     AVFrame *frame;
 };
@@ -27,7 +24,4 @@ struct sc_decoder {
 void
 sc_decoder_init(struct sc_decoder *decoder, const char *name);
 
-void
-sc_decoder_add_sink(struct sc_decoder *decoder, struct sc_frame_sink *sink);
-
 #endif

app/src/delay_buffer.c

@@ -0,0 +1,244 @@
+#include "delay_buffer.h"
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include <libavutil/avutil.h>
+#include <libavformat/avformat.h>
+
+#include "util/log.h"
+
+#define SC_BUFFERING_NDEBUG // comment to debug
+
+/** Downcast frame_sink to sc_delay_buffer */
+#define DOWNCAST(SINK) container_of(SINK, struct sc_delay_buffer, frame_sink)
+
+static bool
+sc_delayed_frame_init(struct sc_delayed_frame *dframe, const AVFrame *frame) {
+    dframe->frame = av_frame_alloc();
+    if (!dframe->frame) {
+        LOG_OOM();
+        return false;
+    }
+
+    if (av_frame_ref(dframe->frame, frame)) {
+        LOG_OOM();
+        av_frame_free(&dframe->frame);
+        return false;
+    }
+
+    return true;
+}
+
+static void
+sc_delayed_frame_destroy(struct sc_delayed_frame *dframe) {
+    av_frame_unref(dframe->frame);
+    av_frame_free(&dframe->frame);
+}
+
+static int
+run_buffering(void *data) {
+    struct sc_delay_buffer *db = data;
+
+    assert(db->delay > 0);
+
+    for (;;) {
+        sc_mutex_lock(&db->mutex);
+
+        while (!db->stopped && sc_vecdeque_is_empty(&db->queue)) {
+            sc_cond_wait(&db->queue_cond, &db->mutex);
+        }
+
+        if (db->stopped) {
+            sc_mutex_unlock(&db->mutex);
+            goto stopped;
+        }
+
+        struct sc_delayed_frame dframe = sc_vecdeque_pop(&db->queue);
+
+        sc_tick max_deadline = sc_tick_now() + db->delay;
+        // PTS (written by the server) are expressed in microseconds
+        sc_tick pts = SC_TICK_TO_US(dframe.frame->pts);
+
+        bool timed_out = false;
+        while (!db->stopped && !timed_out) {
+            sc_tick deadline = sc_clock_to_system_time(&db->clock, pts)
+                             + db->delay;
+            if (deadline > max_deadline) {
+                deadline = max_deadline;
+            }
+
+            timed_out =
+                !sc_cond_timedwait(&db->wait_cond, &db->mutex, deadline);
+        }
+
+        bool stopped = db->stopped;
+        sc_mutex_unlock(&db->mutex);
+
+        if (stopped) {
+            sc_delayed_frame_destroy(&dframe);
+            goto stopped;
+        }
+
+#ifndef SC_BUFFERING_NDEBUG
+        LOGD("Buffering: %" PRItick ";%" PRItick ";%" PRItick,
+             pts, dframe.push_date, sc_tick_now());
+#endif
+
+        bool ok = sc_frame_source_sinks_push(&db->frame_source, dframe.frame);
+        sc_delayed_frame_destroy(&dframe);
+        if (!ok) {
+            LOGE("Delayed frame could not be pushed, stopping");
+            sc_mutex_lock(&db->mutex);
+            // Prevent to push any new frame
+            db->stopped = true;
+            sc_mutex_unlock(&db->mutex);
+            goto stopped;
+        }
+    }
+
+stopped:
+    assert(db->stopped);
+
+    // Flush queue
+    while (!sc_vecdeque_is_empty(&db->queue)) {
+        struct sc_delayed_frame *dframe = sc_vecdeque_popref(&db->queue);
+        sc_delayed_frame_destroy(dframe);
+    }
+
+    LOGD("Buffering thread ended");
+
+    return 0;
+}
+
+static bool
+sc_delay_buffer_frame_sink_open(struct sc_frame_sink *sink,
+                                const AVCodecContext *ctx) {
+    struct sc_delay_buffer *db = DOWNCAST(sink);
+    (void) ctx;
+
+    bool ok = sc_mutex_init(&db->mutex);
+    if (!ok) {
+        return false;
+    }
+
+    ok = sc_cond_init(&db->queue_cond);
+    if (!ok) {
+        goto error_destroy_mutex;
+    }
+
+    ok = sc_cond_init(&db->wait_cond);
+    if (!ok) {
+        goto error_destroy_queue_cond;
+    }
+
+    sc_clock_init(&db->clock);
+    sc_vecdeque_init(&db->queue);
+
+    if (!sc_frame_source_sinks_open(&db->frame_source, ctx)) {
+        goto error_destroy_wait_cond;
+    }
+
+    ok = sc_thread_create(&db->thread, run_buffering, "scrcpy-dbuf", db);
+    if (!ok) {
+        LOGE("Could not start buffering thread");
+        goto error_close_sinks;
+    }
+
+    return true;
+
+error_close_sinks:
+    sc_frame_source_sinks_close(&db->frame_source);
+error_destroy_wait_cond:
+    sc_cond_destroy(&db->wait_cond);
+error_destroy_queue_cond:
+    sc_cond_destroy(&db->queue_cond);
+error_destroy_mutex:
+    sc_mutex_destroy(&db->mutex);
+
+    return false;
+}
+
+static void
+sc_delay_buffer_frame_sink_close(struct sc_frame_sink *sink) {
+    struct sc_delay_buffer *db = DOWNCAST(sink);
+
+    sc_mutex_lock(&db->mutex);
+    db->stopped = true;
+    sc_cond_signal(&db->queue_cond);
+    sc_cond_signal(&db->wait_cond);
+    sc_mutex_unlock(&db->mutex);
+
+    sc_thread_join(&db->thread, NULL);
+
+    sc_frame_source_sinks_close(&db->frame_source);
+
+    sc_cond_destroy(&db->wait_cond);
+    sc_cond_destroy(&db->queue_cond);
+    sc_mutex_destroy(&db->mutex);
+}
+
+static bool
+sc_delay_buffer_frame_sink_push(struct sc_frame_sink *sink,
+                                const AVFrame *frame) {
+    struct sc_delay_buffer *db = DOWNCAST(sink);
+
+    sc_mutex_lock(&db->mutex);
+
+    if (db->stopped) {
+        sc_mutex_unlock(&db->mutex);
+        return false;
+    }
+
+    sc_tick pts = SC_TICK_FROM_US(frame->pts);
+    sc_clock_update(&db->clock, sc_tick_now(), pts);
+    sc_cond_signal(&db->wait_cond);
+
+    if (db->first_frame_asap && db->clock.count == 1) {
+        sc_mutex_unlock(&db->mutex);
+        return sc_frame_source_sinks_push(&db->frame_source, frame);
+    }
+
+    struct sc_delayed_frame dframe;
+    bool ok = sc_delayed_frame_init(&dframe, frame);
+    if (!ok) {
+        sc_mutex_unlock(&db->mutex);
+        return false;
+    }
+
+#ifndef SC_BUFFERING_NDEBUG
+    dframe.push_date = sc_tick_now();
+#endif
+
+    ok = sc_vecdeque_push(&db->queue, dframe);
+    if (!ok) {
+        sc_mutex_unlock(&db->mutex);
+        LOG_OOM();
+        return false;
+    }
+
+    sc_cond_signal(&db->queue_cond);
+
+    sc_mutex_unlock(&db->mutex);
+
+    return true;
+}
+
+void
+sc_delay_buffer_init(struct sc_delay_buffer *db, sc_tick delay,
+                     bool first_frame_asap) {
+    assert(delay > 0);
+
+    db->delay = delay;
+    db->first_frame_asap = first_frame_asap;
+
+    sc_frame_source_init(&db->frame_source);
+
+    static const struct sc_frame_sink_ops ops = {
+        .open = sc_delay_buffer_frame_sink_open,
+        .close = sc_delay_buffer_frame_sink_close,
+        .push = sc_delay_buffer_frame_sink_push,
+    };
+
+    db->frame_sink.ops = &ops;
+}

app/src/delay_buffer.h

@@ -0,0 +1,60 @@
+#ifndef SC_DELAY_BUFFER_H
+#define SC_DELAY_BUFFER_H
+
+#include "common.h"
+
+#include <stdbool.h>
+
+#include "clock.h"
+#include "trait/frame_source.h"
+#include "trait/frame_sink.h"
+#include "util/thread.h"
+#include "util/tick.h"
+#include "util/vecdeque.h"
+
+// forward declarations
+typedef struct AVFrame AVFrame;
+
+struct sc_delayed_frame {
+    AVFrame *frame;
+#ifndef NDEBUG
+    sc_tick push_date;
+#endif
+};
+
+struct sc_delayed_frame_queue SC_VECDEQUE(struct sc_delayed_frame);
+
+struct sc_delay_buffer {
+    struct sc_frame_source frame_source; // frame source trait
+    struct sc_frame_sink frame_sink; // frame sink trait
+
+    sc_tick delay;
+    bool first_frame_asap;
+
+    sc_thread thread;
+    sc_mutex mutex;
+    sc_cond queue_cond;
+    sc_cond wait_cond;
+
+    struct sc_clock clock;
+    struct sc_delayed_frame_queue queue;
+    bool stopped;
+};
+
+struct sc_delay_buffer_callbacks {
+    bool (*on_new_frame)(struct sc_delay_buffer *db, const AVFrame *frame,
+                         void *userdata);
+};
+
+/**
+ * Initialize a delay buffer.
+ *
+ * \param delay a (strictly) positive delay
+ * \param first_frame_asap if true, do not delay the first frame (useful for
+                           a video stream).
+ */
+void
+sc_delay_buffer_init(struct sc_delay_buffer *db, sc_tick delay,
+                     bool first_frame_asap);
+
+#endif

app/src/demuxer.c

@@ -112,86 +112,26 @@ sc_demuxer_recv_packet(struct sc_demuxer *demuxer, AVPacket *packet) {
     return true;
 }
 
-static bool
-push_packet_to_sinks(struct sc_demuxer *demuxer, const AVPacket *packet) {
-    for (unsigned i = 0; i < demuxer->sink_count; ++i) {
-        struct sc_packet_sink *sink = demuxer->sinks[i];
-        if (!sink->ops->push(sink, packet)) {
-            return false;
-        }
-    }
-
-    return true;
-}
-
-static bool
-sc_demuxer_push_packet(struct sc_demuxer *demuxer, AVPacket *packet) {
-    bool ok = push_packet_to_sinks(demuxer, packet);
-    if (!ok) {
-        LOGE("Demuxer '%s': could not process packet", demuxer->name);
-        return false;
-    }
-
-    return true;
-}
-
-static void
-sc_demuxer_close_first_sinks(struct sc_demuxer *demuxer, unsigned count) {
-    while (count) {
-        struct sc_packet_sink *sink = demuxer->sinks[--count];
-        sink->ops->close(sink);
-    }
-}
-
-static inline void
-sc_demuxer_close_sinks(struct sc_demuxer *demuxer) {
-    sc_demuxer_close_first_sinks(demuxer, demuxer->sink_count);
-}
-
-static bool
-sc_demuxer_open_sinks(struct sc_demuxer *demuxer, const AVCodec *codec) {
-    for (unsigned i = 0; i < demuxer->sink_count; ++i) {
-        struct sc_packet_sink *sink = demuxer->sinks[i];
-        if (!sink->ops->open(sink, codec)) {
-            sc_demuxer_close_first_sinks(demuxer, i);
-            return false;
-        }
-    }
-
-    return true;
-}
-
-static void
-sc_demuxer_disable_sinks(struct sc_demuxer *demuxer) {
-    for (unsigned i = 0; i < demuxer->sink_count; ++i) {
-        struct sc_packet_sink *sink = demuxer->sinks[i];
-        if (sink->ops->disable) {
-            sink->ops->disable(sink);
-        }
-    }
-}
-
 static int
 run_demuxer(void *data) {
     struct sc_demuxer *demuxer = data;
 
     // Flag to report end-of-stream (i.e. device disconnected)
-    bool eos = false;
+    enum sc_demuxer_status status = SC_DEMUXER_STATUS_ERROR;
 
     uint32_t raw_codec_id;
     bool ok = sc_demuxer_recv_codec_id(demuxer, &raw_codec_id);
     if (!ok) {
         LOGE("Demuxer '%s': stream disabled due to connection error",
              demuxer->name);
-        eos = true;
         goto end;
     }
 
     if (raw_codec_id == 0) {
         LOGW("Demuxer '%s': stream explicitly disabled by the device",
              demuxer->name);
-        sc_demuxer_disable_sinks(demuxer);
-        eos = true;
+        sc_packet_source_sinks_disable(&demuxer->packet_source);
+        status = SC_DEMUXER_STATUS_DISABLED;
         goto end;
     }
 
@@ -205,7 +145,7 @@ run_demuxer(void *data) {
     if (codec_id == AV_CODEC_ID_NONE) {
         LOGE("Demuxer '%s': stream disabled due to unsupported codec",
              demuxer->name);
-        sc_demuxer_disable_sinks(demuxer);
+        sc_packet_source_sinks_disable(&demuxer->packet_source);
         goto end;
     }
 
@@ -213,11 +153,11 @@ run_demuxer(void *data) {
     if (!codec) {
         LOGE("Demuxer '%s': stream disabled due to missing decoder",
              demuxer->name);
-        sc_demuxer_disable_sinks(demuxer);
+        sc_packet_source_sinks_disable(&demuxer->packet_source);
         goto end;
     }
 
-    if (!sc_demuxer_open_sinks(demuxer, codec)) {
+    if (!sc_packet_source_sinks_open(&demuxer->packet_source, codec)) {
         goto end;
     }
 
@@ -241,7 +181,7 @@ run_demuxer(void *data) {
         bool ok = sc_demuxer_recv_packet(demuxer, packet);
         if (!ok) {
             // end of stream
-            eos = true;
+            status = SC_DEMUXER_STATUS_EOS;
             break;
         }
 
@@ -254,10 +194,10 @@ run_demuxer(void *data) {
             }
         }
 
-        ok = sc_demuxer_push_packet(demuxer, packet);
+        ok = sc_packet_source_sinks_push(&demuxer->packet_source, packet);
         av_packet_unref(packet);
         if (!ok) {
-            // cannot process packet (error already logged)
+            LOGE("Demuxer '%s': could not process packet", demuxer->name);
             break;
         }
     }
@@ -270,9 +210,9 @@ run_demuxer(void *data) {
 
     av_packet_free(&packet);
 finally_close_sinks:
-    sc_demuxer_close_sinks(demuxer);
+    sc_packet_source_sinks_close(&demuxer->packet_source);
 end:
-    demuxer->cbs->on_ended(demuxer, eos, demuxer->cbs_userdata);
+    demuxer->cbs->on_ended(demuxer, status, demuxer->cbs_userdata);
 
     return 0;
 }
@@ -284,7 +224,7 @@ sc_demuxer_init(struct sc_demuxer *demuxer, const char *name, sc_socket socket,
 
     demuxer->name = name; // statically allocated
     demuxer->socket = socket;
-    demuxer->sink_count = 0;
+    sc_packet_source_init(&demuxer->packet_source);
 
     assert(cbs && cbs->on_ended);
 
@@ -292,14 +232,6 @@ sc_demuxer_init(struct sc_demuxer *demuxer, const char *name, sc_socket socket,
     demuxer->cbs_userdata = cbs_userdata;
 }
 
-void
-sc_demuxer_add_sink(struct sc_demuxer *demuxer, struct sc_packet_sink *sink) {
-    assert(demuxer->sink_count < SC_DEMUXER_MAX_SINKS);
-    assert(sink);
-    assert(sink->ops);
-    demuxer->sinks[demuxer->sink_count++] = sink;
-}
-
 bool
 sc_demuxer_start(struct sc_demuxer *demuxer) {
     LOGD("Demuxer '%s': starting thread", demuxer->name);

app/src/demuxer.h

@@ -8,27 +8,32 @@
 #include <libavcodec/avcodec.h>
 #include <libavformat/avformat.h>
 
+#include "trait/packet_source.h"
 #include "trait/packet_sink.h"
 #include "util/net.h"
 #include "util/thread.h"
 
-#define SC_DEMUXER_MAX_SINKS 2
-
 struct sc_demuxer {
+    struct sc_packet_source packet_source; // packet source trait
+
     const char *name; // must be statically allocated (e.g. a string literal)
 
     sc_socket socket;
     sc_thread thread;
 
-    struct sc_packet_sink *sinks[SC_DEMUXER_MAX_SINKS];
-    unsigned sink_count;
-
     const struct sc_demuxer_callbacks *cbs;
     void *cbs_userdata;
 };
 
+enum sc_demuxer_status {
+    SC_DEMUXER_STATUS_EOS,
+    SC_DEMUXER_STATUS_DISABLED,
+    SC_DEMUXER_STATUS_ERROR,
+};
+
 struct sc_demuxer_callbacks {
-    void (*on_ended)(struct sc_demuxer *demuxer, bool eos, void *userdata);
+    void (*on_ended)(struct sc_demuxer *demuxer, enum sc_demuxer_status,
+                     void *userdata);
 };
 
 // The name must be statically allocated (e.g. a string literal)
@@ -36,9 +41,6 @@ void
 sc_demuxer_init(struct sc_demuxer *demuxer, const char *name, sc_socket socket,
                 const struct sc_demuxer_callbacks *cbs, void *cbs_userdata);
 
-void
-sc_demuxer_add_sink(struct sc_demuxer *demuxer, struct sc_packet_sink *sink);
-
 bool
 sc_demuxer_start(struct sc_demuxer *demuxer);
 

app/src/file_pusher.c

@@ -19,7 +19,7 @@ sc_file_pusher_init(struct sc_file_pusher *fp, const char *serial,
                     const char *push_target) {
     assert(serial);
 
-    cbuf_init(&fp->queue);
+    sc_vecdeque_init(&fp->queue);
 
     bool ok = sc_mutex_init(&fp->mutex);
     if (!ok) {
@@ -65,9 +65,10 @@ sc_file_pusher_destroy(struct sc_file_pusher *fp) {
     sc_intr_destroy(&fp->intr);
     free(fp->serial);
 
-    struct sc_file_pusher_request req;
-    while (cbuf_take(&fp->queue, &req)) {
-        sc_file_pusher_request_destroy(&req);
+    while (!sc_vecdeque_is_empty(&fp->queue)) {
+        struct sc_file_pusher_request *req = sc_vecdeque_popref(&fp->queue);
+        assert(req);
+        sc_file_pusher_request_destroy(req);
     }
 }
 
@@ -91,13 +92,20 @@ sc_file_pusher_request(struct sc_file_pusher *fp,
     };
 
     sc_mutex_lock(&fp->mutex);
-    bool was_empty = cbuf_is_empty(&fp->queue);
-    bool res = cbuf_push(&fp->queue, req);
+    bool was_empty = sc_vecdeque_is_empty(&fp->queue);
+    bool res = sc_vecdeque_push(&fp->queue, req);
+    if (!res) {
+        LOG_OOM();
+        sc_mutex_unlock(&fp->mutex);
+        return false;
+    }
+
     if (was_empty) {
         sc_cond_signal(&fp->event_cond);
     }
     sc_mutex_unlock(&fp->mutex);
-    return res;
+
+    return true;
 }
 
 static int
@@ -113,7 +121,7 @@ run_file_pusher(void *data) {
 
     for (;;) {
         sc_mutex_lock(&fp->mutex);
-        while (!fp->stopped && cbuf_is_empty(&fp->queue)) {
+        while (!fp->stopped && sc_vecdeque_is_empty(&fp->queue)) {
             sc_cond_wait(&fp->event_cond, &fp->mutex);
         }
         if (fp->stopped) {
@@ -121,10 +129,9 @@ run_file_pusher(void *data) {
             sc_mutex_unlock(&fp->mutex);
             break;
         }
-        struct sc_file_pusher_request req;
-        bool non_empty = cbuf_take(&fp->queue, &req);
-        assert(non_empty);
-        (void) non_empty;
+
+        assert(!sc_vecdeque_is_empty(&fp->queue));
+        struct sc_file_pusher_request req = sc_vecdeque_pop(&fp->queue);
         sc_mutex_unlock(&fp->mutex);
 
         if (req.action == SC_FILE_PUSHER_ACTION_INSTALL_APK) {

app/src/file_pusher.h

@@ -5,9 +5,9 @@
 
 #include <stdbool.h>
 
-#include "util/cbuf.h"
-#include "util/thread.h"
 #include "util/intr.h"
+#include "util/thread.h"
+#include "util/vecdeque.h"
 
 enum sc_file_pusher_action {
     SC_FILE_PUSHER_ACTION_INSTALL_APK,
@@ -19,7 +19,7 @@ struct sc_file_pusher_request {
     char *file;
 };
 
-struct sc_file_pusher_request_queue CBUF(struct sc_file_pusher_request, 16);
+struct sc_file_pusher_request_queue SC_VECDEQUE(struct sc_file_pusher_request);
 
 struct sc_file_pusher {
     char *serial;

app/src/options.c

@@ -43,6 +43,7 @@ const struct scrcpy_options scrcpy_options_default = {
     .display_id = 0,
     .display_buffer = 0,
     .v4l2_buffer = 0,
+    .audio_buffer = 0,
 #ifdef HAVE_USB
     .otg = false,
 #endif
@@ -72,6 +73,7 @@ const struct scrcpy_options scrcpy_options_default = {
     .start_fps_counter = false,
     .power_on = true,
     .audio = true,
+    .require_audio = false,
     .list_encoders = false,
     .list_displays = false,
 };

app/src/options.h

@@ -125,6 +125,7 @@ struct scrcpy_options {
     uint32_t display_id;
     sc_tick display_buffer;
     sc_tick v4l2_buffer;
+    sc_tick audio_buffer;
 #ifdef HAVE_USB
     bool otg;
 #endif
@@ -154,6 +155,7 @@ struct scrcpy_options {
     bool start_fps_counter;
     bool power_on;
     bool audio;
+    bool require_audio;
     bool list_encoders;
     bool list_displays;
 };

app/src/recorder.c

@@ -33,41 +33,27 @@ find_muxer(const char *name) {
     return oformat;
 }
 
-static struct sc_record_packet *
-sc_record_packet_new(const AVPacket *packet) {
-    struct sc_record_packet *rec = malloc(sizeof(*rec));
-    if (!rec) {
+static AVPacket *
+sc_recorder_packet_ref(const AVPacket *packet) {
+    AVPacket *p = av_packet_alloc();
+    if (!p) {
         LOG_OOM();
         return NULL;
     }
 
-    rec->packet = av_packet_alloc();
-    if (!rec->packet) {
-        LOG_OOM();
-        free(rec);
+    if (av_packet_ref(p, packet)) {
+        av_packet_free(&p);
         return NULL;
     }
 
-    if (av_packet_ref(rec->packet, packet)) {
-        av_packet_free(&rec->packet);
-        free(rec);
-        return NULL;
-    }
-    return rec;
-}
-
-static void
-sc_record_packet_delete(struct sc_record_packet *rec) {
-    av_packet_free(&rec->packet);
-    free(rec);
+    return p;
 }
 
 static void
 sc_recorder_queue_clear(struct sc_recorder_queue *queue) {
-    while (!sc_queue_is_empty(queue)) {
-        struct sc_record_packet *rec;
-        sc_queue_take(queue, next, &rec);
-        sc_record_packet_delete(rec);
+    while (!sc_vecdeque_is_empty(queue)) {
+        AVPacket *p = sc_vecdeque_pop(queue);
+        av_packet_free(&p);
     }
 }
 
@@ -232,12 +218,12 @@ sc_recorder_wait_audio_stream(struct sc_recorder *recorder) {
 
 static inline bool
 sc_recorder_has_empty_queues(struct sc_recorder *recorder) {
-    if (sc_queue_is_empty(&recorder->video_queue)) {
+    if (sc_vecdeque_is_empty(&recorder->video_queue)) {
         // The video queue is empty
         return true;
     }
 
-    if (recorder->audio && sc_queue_is_empty(&recorder->audio_queue)) {
+    if (recorder->audio && sc_vecdeque_is_empty(&recorder->audio_queue)) {
         // The audio queue is empty (when audio is enabled)
         return true;
     }
@@ -254,27 +240,26 @@ sc_recorder_process_header(struct sc_recorder *recorder) {
         sc_cond_wait(&recorder->queue_cond, &recorder->mutex);
     }
 
-    if (recorder->stopped && sc_queue_is_empty(&recorder->video_queue)) {
+    if (recorder->stopped && sc_vecdeque_is_empty(&recorder->video_queue)) {
         // If the recorder is stopped, don't process anything if there are not
         // at least video packets
         sc_mutex_unlock(&recorder->mutex);
         return false;
     }
 
-    struct sc_record_packet *video_pkt;
-    sc_queue_take(&recorder->video_queue, next, &video_pkt);
+    AVPacket *video_pkt = sc_vecdeque_pop(&recorder->video_queue);
 
-    struct sc_record_packet *audio_pkt = NULL;
-    if (!sc_queue_is_empty(&recorder->audio_queue)) {
+    AVPacket *audio_pkt = NULL;
+    if (!sc_vecdeque_is_empty(&recorder->audio_queue)) {
         assert(recorder->audio);
-        sc_queue_take(&recorder->audio_queue, next, &audio_pkt);
+        audio_pkt = sc_vecdeque_pop(&recorder->audio_queue);
     }
 
     sc_mutex_unlock(&recorder->mutex);
 
     int ret = false;
 
-    if (video_pkt->packet->pts != AV_NOPTS_VALUE) {
+    if (video_pkt->pts != AV_NOPTS_VALUE) {
         LOGE("The first video packet is not a config packet");
         goto end;
     }
@@ -282,13 +267,13 @@ sc_recorder_process_header(struct sc_recorder *recorder) {
     assert(recorder->video_stream_index >= 0);
     AVStream *video_stream =
         recorder->ctx->streams[recorder->video_stream_index];
-    bool ok = sc_recorder_set_extradata(video_stream, video_pkt->packet);
+    bool ok = sc_recorder_set_extradata(video_stream, video_pkt);
     if (!ok) {
         goto end;
     }
 
     if (audio_pkt) {
-        if (audio_pkt->packet->pts != AV_NOPTS_VALUE) {
+        if (audio_pkt->pts != AV_NOPTS_VALUE) {
             LOGE("The first audio packet is not a config packet");
             goto end;
         }
@@ -296,7 +281,7 @@ sc_recorder_process_header(struct sc_recorder *recorder) {
         assert(recorder->audio_stream_index >= 0);
         AVStream *audio_stream =
             recorder->ctx->streams[recorder->audio_stream_index];
-        ok = sc_recorder_set_extradata(audio_stream, audio_pkt->packet);
+        ok = sc_recorder_set_extradata(audio_stream, audio_pkt);
         if (!ok) {
             goto end;
         }
@@ -311,9 +296,9 @@ sc_recorder_process_header(struct sc_recorder *recorder) {
     ret = true;
 
 end:
-    sc_record_packet_delete(video_pkt);
+    av_packet_free(&video_pkt);
     if (audio_pkt) {
-        sc_record_packet_delete(audio_pkt);
+        av_packet_free(&audio_pkt);
     }
 
     return ret;
@@ -328,12 +313,12 @@ sc_recorder_process_packets(struct sc_recorder *recorder) {
         return false;
     }
 
-    struct sc_record_packet *video_pkt = NULL;
-    struct sc_record_packet *audio_pkt = NULL;
+    AVPacket *video_pkt = NULL;
+    AVPacket *audio_pkt = NULL;
 
     // We can write a video packet only once we received the next one so that
     // we can set its duration (next_pts - current_pts)
-    struct sc_record_packet *video_pkt_previous = NULL;
+    AVPacket *video_pkt_previous = NULL;
 
     bool error = false;
 
@@ -341,12 +326,12 @@ sc_recorder_process_packets(struct sc_recorder *recorder) {
         sc_mutex_lock(&recorder->mutex);
 
         while (!recorder->stopped) {
-            if (!video_pkt && !sc_queue_is_empty(&recorder->video_queue)) {
+            if (!video_pkt && !sc_vecdeque_is_empty(&recorder->video_queue)) {
                 // A new packet may be assigned to video_pkt and be processed
                 break;
             }
             if (recorder->audio && !audio_pkt
-                    && !sc_queue_is_empty(&recorder->audio_queue)) {
+                    && !sc_vecdeque_is_empty(&recorder->audio_queue)) {
                 // A new packet may be assigned to audio_pkt and be processed
                 break;
             }
@@ -358,20 +343,20 @@ sc_recorder_process_packets(struct sc_recorder *recorder) {
 
         // If there is no audio, then the audio_queue will remain empty forever
         // and audio_pkt will always be NULL.
-        assert(recorder->audio
-                || (!audio_pkt && sc_queue_is_empty(&recorder->audio_queue)));
+        assert(recorder->audio || (!audio_pkt
+                && sc_vecdeque_is_empty(&recorder->audio_queue)));
 
-        if (!video_pkt && !sc_queue_is_empty(&recorder->video_queue)) {
-            sc_queue_take(&recorder->video_queue, next, &video_pkt);
+        if (!video_pkt && !sc_vecdeque_is_empty(&recorder->video_queue)) {
+            video_pkt = sc_vecdeque_pop(&recorder->video_queue);
         }
 
-        if (!audio_pkt && !sc_queue_is_empty(&recorder->audio_queue)) {
-            sc_queue_take(&recorder->audio_queue, next, &audio_pkt);
+        if (!audio_pkt && !sc_vecdeque_is_empty(&recorder->audio_queue)) {
+            audio_pkt = sc_vecdeque_pop(&recorder->audio_queue);
         }
 
         if (recorder->stopped && !video_pkt && !audio_pkt) {
-            assert(sc_queue_is_empty(&recorder->video_queue));
-            assert(sc_queue_is_empty(&recorder->audio_queue));
+            assert(sc_vecdeque_is_empty(&recorder->video_queue));
+            assert(sc_vecdeque_is_empty(&recorder->audio_queue));
             sc_mutex_unlock(&recorder->mutex);
             break;
         }
@@ -383,28 +368,27 @@ sc_recorder_process_packets(struct sc_recorder *recorder) {
         // Ignore further config packets (e.g. on device orientation
         // change). The next non-config packet will have the config packet
         // data prepended.
-        if (video_pkt && video_pkt->packet->pts == AV_NOPTS_VALUE) {
-            sc_record_packet_delete(video_pkt);
+        if (video_pkt && video_pkt->pts == AV_NOPTS_VALUE) {
+            av_packet_free(&video_pkt);
             video_pkt = NULL;
         }
 
-        if (audio_pkt && audio_pkt->packet->pts == AV_NOPTS_VALUE) {
-            sc_record_packet_delete(audio_pkt);
-            audio_pkt= NULL;
+        if (audio_pkt && audio_pkt->pts == AV_NOPTS_VALUE) {
+            av_packet_free(&audio_pkt);
+            audio_pkt = NULL;
         }
 
         if (pts_origin == AV_NOPTS_VALUE) {
             if (!recorder->audio) {
                 assert(video_pkt);
-                pts_origin = video_pkt->packet->pts;
+                pts_origin = video_pkt->pts;
             } else if (video_pkt && audio_pkt) {
-                pts_origin =
-                    MIN(video_pkt->packet->pts, audio_pkt->packet->pts);
+                pts_origin = MIN(video_pkt->pts, audio_pkt->pts);
             } else if (recorder->stopped) {
                 if (video_pkt) {
                     // The recorder is stopped without audio, record the video
                     // packets
-                    pts_origin = video_pkt->packet->pts;
+                    pts_origin = video_pkt->pts;
                 } else {
                     // Fail if there is no video
                     error = true;
@@ -413,8 +397,7 @@ sc_recorder_process_packets(struct sc_recorder *recorder) {
                 // If the recorder is stopped while one of the streams has no
                 // packets, then we must avoid a live-loop and correctly record
                 // the stream having packets.
-                pts_origin = video_pkt ? video_pkt->packet->pts
-                                       : audio_pkt->packet->pts;
+                pts_origin = video_pkt ? video_pkt->pts : audio_pkt->pts;
             } else {
                 // We need both video and audio packets to initialize pts_origin
                 continue;
@@ -424,17 +407,16 @@ sc_recorder_process_packets(struct sc_recorder *recorder) {
         assert(pts_origin != AV_NOPTS_VALUE);
 
         if (video_pkt) {
-            video_pkt->packet->pts -= pts_origin;
-            video_pkt->packet->dts = video_pkt->packet->pts;
+            video_pkt->pts -= pts_origin;
+            video_pkt->dts = video_pkt->pts;
 
             if (video_pkt_previous) {
                 // we now know the duration of the previous packet
-                video_pkt_previous->packet->duration =
-                    video_pkt->packet->pts - video_pkt_previous->packet->pts;
+                video_pkt_previous->duration = video_pkt->pts
+                                             - video_pkt_previous->pts;
 
-                bool ok = sc_recorder_write_video(recorder,
-                                                  video_pkt_previous->packet);
-                sc_record_packet_delete(video_pkt_previous);
+                bool ok = sc_recorder_write_video(recorder, video_pkt_previous);
+                av_packet_free(&video_pkt_previous);
                 if (!ok) {
                     LOGE("Could not record video packet");
                     error = true;
@@ -447,34 +429,34 @@ sc_recorder_process_packets(struct sc_recorder *recorder) {
         }
 
         if (audio_pkt) {
-            audio_pkt->packet->pts -= pts_origin;
-            audio_pkt->packet->dts = audio_pkt->packet->pts;
+            audio_pkt->pts -= pts_origin;
+            audio_pkt->dts = audio_pkt->pts;
 
-            bool ok = sc_recorder_write_audio(recorder, audio_pkt->packet);
+            bool ok = sc_recorder_write_audio(recorder, audio_pkt);
             if (!ok) {
                 LOGE("Could not record audio packet");
                 error = true;
                 goto end;
             }
 
-            sc_record_packet_delete(audio_pkt);
+            av_packet_free(&audio_pkt);
             audio_pkt = NULL;
         }
     }
 
     // Write the last video packet
-    struct sc_record_packet *last = video_pkt_previous;
+    AVPacket *last = video_pkt_previous;
     if (last) {
         // assign an arbitrary duration to the last packet
-        last->packet->duration = 100000;
-        bool ok = sc_recorder_write_video(recorder, last->packet);
+        last->duration = 100000;
+        bool ok = sc_recorder_write_video(recorder, last);
         if (!ok) {
             // failing to write the last frame is not very serious, no
             // future frame may depend on it, so the resulting file
             // will still be valid
             LOGW("Could not record last packet");
         }
-        sc_record_packet_delete(last);
+        av_packet_free(&last);
     }
 
     int ret = av_write_trailer(recorder->ctx);
@@ -485,10 +467,10 @@ sc_recorder_process_packets(struct sc_recorder *recorder) {
 
 end:
     if (video_pkt) {
-        sc_record_packet_delete(video_pkt);
+        av_packet_free(&video_pkt);
     }
     if (audio_pkt) {
-        sc_record_packet_delete(audio_pkt);
+        av_packet_free(&audio_pkt);
     }
 
     return !error;
@@ -533,6 +515,7 @@ run_recorder(void *data) {
     recorder->stopped = true;
     // Discard pending packets
     sc_recorder_queue_clear(&recorder->video_queue);
+    sc_recorder_queue_clear(&recorder->audio_queue);
     sc_mutex_unlock(&recorder->mutex);
 
     if (success) {
@@ -593,16 +576,22 @@ sc_recorder_video_packet_sink_push(struct sc_packet_sink *sink,
         return false;
     }
 
-    struct sc_record_packet *rec = sc_record_packet_new(packet);
+    AVPacket *rec = sc_recorder_packet_ref(packet);
     if (!rec) {
         LOG_OOM();
         sc_mutex_unlock(&recorder->mutex);
         return false;
     }
 
-    rec->packet->stream_index = 0;
+    rec->stream_index = 0;
+
+    bool ok = sc_vecdeque_push(&recorder->video_queue, rec);
+    if (!ok) {
+        LOG_OOM();
+        sc_mutex_unlock(&recorder->mutex);
+        return false;
+    }
 
-    sc_queue_push(&recorder->video_queue, next, rec);
     sc_cond_signal(&recorder->queue_cond);
 
     sc_mutex_unlock(&recorder->mutex);
@@ -656,16 +645,22 @@ sc_recorder_audio_packet_sink_push(struct sc_packet_sink *sink,
         return false;
     }
 
-    struct sc_record_packet *rec = sc_record_packet_new(packet);
+    AVPacket *rec = sc_recorder_packet_ref(packet);
     if (!rec) {
         LOG_OOM();
         sc_mutex_unlock(&recorder->mutex);
         return false;
     }
 
-    rec->packet->stream_index = 1;
+    rec->stream_index = 1;
+
+    bool ok = sc_vecdeque_push(&recorder->audio_queue, rec);
+    if (!ok) {
+        LOG_OOM();
+        sc_mutex_unlock(&recorder->mutex);
+        return false;
+    }
 
-    sc_queue_push(&recorder->audio_queue, next, rec);
     sc_cond_signal(&recorder->queue_cond);
 
     sc_mutex_unlock(&recorder->mutex);
@@ -716,8 +711,8 @@ sc_recorder_init(struct sc_recorder *recorder, const char *filename,
 
     recorder->audio = audio;
 
-    sc_queue_init(&recorder->video_queue);
-    sc_queue_init(&recorder->audio_queue);
+    sc_vecdeque_init(&recorder->video_queue);
+    sc_vecdeque_init(&recorder->audio_queue);
     recorder->stopped = false;
 
     recorder->video_codec = NULL;

app/src/recorder.h

@@ -9,15 +9,10 @@
 #include "coords.h"
 #include "options.h"
 #include "trait/packet_sink.h"
-#include "util/queue.h"
 #include "util/thread.h"
+#include "util/vecdeque.h"
 
-struct sc_record_packet {
-    AVPacket *packet;
-    struct sc_record_packet *next;
-};
-
-struct sc_recorder_queue SC_QUEUE(struct sc_record_packet);
+struct sc_recorder_queue SC_VECDEQUE(AVPacket *);
 
 struct sc_recorder {
     struct sc_packet_sink video_packet_sink;

app/src/scrcpy.c

@@ -16,6 +16,7 @@
 #include "audio_player.h"
 #include "controller.h"
 #include "decoder.h"
+#include "delay_buffer.h"
 #include "demuxer.h"
 #include "events.h"
 #include "file_pusher.h"
@@ -42,13 +43,16 @@ struct scrcpy {
     struct sc_server server;
     struct sc_screen screen;
     struct sc_audio_player audio_player;
+    struct sc_delay_buffer audio_buffer;
     struct sc_demuxer video_demuxer;
     struct sc_demuxer audio_demuxer;
     struct sc_decoder video_decoder;
     struct sc_decoder audio_decoder;
     struct sc_recorder recorder;
+    struct sc_delay_buffer display_buffer;
 #ifdef HAVE_V4L2
     struct sc_v4l2_sink v4l2_sink;
+    struct sc_delay_buffer v4l2_buffer;
 #endif
     struct sc_controller controller;
     struct sc_file_pusher file_pusher;
@@ -218,12 +222,15 @@ sc_recorder_on_ended(struct sc_recorder *recorder, bool success,
 }
 
 static void
-sc_video_demuxer_on_ended(struct sc_demuxer *demuxer, bool eos,
-                          void *userdata) {
+sc_video_demuxer_on_ended(struct sc_demuxer *demuxer,
+                          enum sc_demuxer_status status, void *userdata) {
     (void) demuxer;
     (void) userdata;
 
-    if (eos) {
+    // The device may not decide to disable the video
+    assert(status != SC_DEMUXER_STATUS_DISABLED);
+
+    if (status == SC_DEMUXER_STATUS_EOS) {
         PUSH_EVENT(SC_EVENT_DEVICE_DISCONNECTED);
     } else {
         PUSH_EVENT(SC_EVENT_DEMUXER_ERROR);
@@ -231,12 +238,14 @@ sc_video_demuxer_on_ended(struct sc_demuxer *demuxer, bool eos,
 }
 
 static void
-sc_audio_demuxer_on_ended(struct sc_demuxer *demuxer, bool eos,
-                          void *userdata) {
+sc_audio_demuxer_on_ended(struct sc_demuxer *demuxer,
+                          enum sc_demuxer_status status, void *userdata) {
     (void) demuxer;
-    (void) userdata;
 
-    // Contrary to the video demuxer, keep mirroring if only the audio fails.
+    const struct scrcpy_options *options = userdata;
+
+    // Contrary to the video demuxer, keep mirroring if only the audio fails
+    // (unless --require-audio is set).
     // 'eos' is true on end-of-stream, including when audio capture is not
     // possible on the device (so that scrcpy continue to mirror video without
     // failing).
@@ -244,7 +253,9 @@ sc_audio_demuxer_on_ended(struct sc_demuxer *demuxer, bool eos,
     // explicitly selected an unknown audio encoder), 'eos' is false and scrcpy
     // must exit.
 
-    if (!eos) {
+    if (status == SC_DEMUXER_STATUS_ERROR
+            || (status == SC_DEMUXER_STATUS_DISABLED
+                && options->require_audio)) {
         PUSH_EVENT(SC_EVENT_DEMUXER_ERROR);
     }
 }
@@ -443,7 +454,7 @@ scrcpy(struct scrcpy_options *options) {
             .on_ended = sc_audio_demuxer_on_ended,
         };
         sc_demuxer_init(&s->audio_demuxer, "audio", s->server.audio_socket,
-                        &audio_demuxer_cbs, NULL);
+                        &audio_demuxer_cbs, options);
     }
 
     bool needs_video_decoder = options->display;
@@ -453,11 +464,13 @@ scrcpy(struct scrcpy_options *options) {
 #endif
     if (needs_video_decoder) {
         sc_decoder_init(&s->video_decoder, "video");
-        sc_demuxer_add_sink(&s->video_demuxer, &s->video_decoder.packet_sink);
+        sc_packet_source_add_sink(&s->video_demuxer.packet_source,
+                                  &s->video_decoder.packet_sink);
     }
     if (needs_audio_decoder) {
         sc_decoder_init(&s->audio_decoder, "audio");
-        sc_demuxer_add_sink(&s->audio_demuxer, &s->audio_decoder.packet_sink);
+        sc_packet_source_add_sink(&s->audio_demuxer.packet_source,
+                                  &s->audio_decoder.packet_sink);
     }
 
     if (options->record_filename) {
@@ -476,10 +489,11 @@ scrcpy(struct scrcpy_options *options) {
         }
         recorder_started = true;
 
-        sc_demuxer_add_sink(&s->video_demuxer, &s->recorder.video_packet_sink);
+        sc_packet_source_add_sink(&s->video_demuxer.packet_source,
+                                  &s->recorder.video_packet_sink);
         if (options->audio) {
-            sc_demuxer_add_sink(&s->audio_demuxer,
-                                &s->recorder.audio_packet_sink);
+            sc_packet_source_add_sink(&s->audio_demuxer.packet_source,
+                                      &s->recorder.audio_packet_sink);
         }
     }
 
@@ -663,7 +677,6 @@ aoa_hid_end:
             .mipmaps = options->mipmaps,
             .fullscreen = options->fullscreen,
             .start_fps_counter = options->start_fps_counter,
-            .buffering_time = options->display_buffer,
         };
 
         if (!sc_screen_init(&s->screen, &screen_params)) {
@@ -671,22 +684,45 @@ aoa_hid_end:
         }
         screen_initialized = true;
 
-        sc_decoder_add_sink(&s->video_decoder, &s->screen.frame_sink);
+        struct sc_frame_source *src = &s->video_decoder.frame_source;
+        if (options->display_buffer) {
+            sc_delay_buffer_init(&s->display_buffer, options->display_buffer,
+                                 true);
+            sc_frame_source_add_sink(src, &s->display_buffer.frame_sink);
+            src = &s->display_buffer.frame_source;
+        }
+
+        sc_frame_source_add_sink(src, &s->screen.frame_sink);
 
         if (options->audio) {
+            struct sc_frame_source *src = &s->audio_decoder.frame_source;
+            if (options->audio_buffer) {
+                sc_delay_buffer_init(&s->audio_buffer, options->audio_buffer,
+                                     false);
+                sc_frame_source_add_sink(src, &s->audio_buffer.frame_sink);
+                src = &s->audio_buffer.frame_source;
+            }
+
             sc_audio_player_init(&s->audio_player);
-            sc_decoder_add_sink(&s->audio_decoder, &s->audio_player.frame_sink);
+            sc_frame_source_add_sink(src, &s->audio_player.frame_sink);
         }
     }
 
 #ifdef HAVE_V4L2
     if (options->v4l2_device) {
         if (!sc_v4l2_sink_init(&s->v4l2_sink, options->v4l2_device,
-                               info->frame_size, options->v4l2_buffer)) {
+                               info->frame_size)) {
             goto end;
         }
 
-        sc_decoder_add_sink(&s->video_decoder, &s->v4l2_sink.frame_sink);
+        struct sc_frame_source *src = &s->video_decoder.frame_source;
+        if (options->v4l2_buffer) {
+            sc_delay_buffer_init(&s->v4l2_buffer, options->v4l2_buffer, true);
+            sc_frame_source_add_sink(src, &s->v4l2_buffer.frame_sink);
+            src = &s->v4l2_buffer.frame_source;
+        }
+
+        sc_frame_source_add_sink(src, &s->v4l2_sink.frame_sink);
 
         v4l2_sink_initialized = true;
     }

app/src/screen.c

@@ -7,7 +7,6 @@
 #include "events.h"
 #include "icon.h"
 #include "options.h"
-#include "video_buffer.h"
 #include "util/log.h"
 
 #define DISPLAY_MARGINS 96
@@ -359,30 +358,18 @@ sc_screen_frame_sink_close(struct sc_frame_sink *sink) {
 static bool
 sc_screen_frame_sink_push(struct sc_frame_sink *sink, const AVFrame *frame) {
     struct sc_screen *screen = DOWNCAST(sink);
-    return sc_video_buffer_push(&screen->vb, frame);
-}
 
-static void
-sc_video_buffer_on_new_frame(struct sc_video_buffer *vb, bool previous_skipped,
-                             void *userdata) {
-    (void) vb;
-    struct sc_screen *screen = userdata;
+    bool previous_skipped;
+    bool ok = sc_frame_buffer_push(&screen->fb, frame, &previous_skipped);
+    if (!ok) {
+        return false;
+    }
 
-    // event_failed implies previous_skipped (the previous frame may not have
-    // been consumed if the event was not sent)
-    assert(!screen->event_failed || previous_skipped);
-
-    bool need_new_event;
     if (previous_skipped) {
         sc_fps_counter_add_skipped_frame(&screen->fps_counter);
         // The SC_EVENT_NEW_FRAME triggered for the previous frame will consume
-        // this new frame instead, unless the previous event failed
-        need_new_event = screen->event_failed;
+        // this new frame instead
     } else {
-        need_new_event = true;
-    }
-
-    if (need_new_event) {
         static SDL_Event new_frame_event = {
             .type = SC_EVENT_NEW_FRAME,
         };
@@ -391,11 +378,11 @@ sc_video_buffer_on_new_frame(struct sc_video_buffer *vb, bool previous_skipped,
         int ret = SDL_PushEvent(&new_frame_event);
         if (ret < 0) {
             LOGW("Could not post new frame event: %s", SDL_GetError());
-            screen->event_failed = true;
-        } else {
-            screen->event_failed = false;
+            return false;
         }
     }
+
+    return true;
 }
 
 bool
@@ -405,7 +392,6 @@ sc_screen_init(struct sc_screen *screen,
     screen->has_frame = false;
     screen->fullscreen = false;
     screen->maximized = false;
-    screen->event_failed = false;
     screen->mouse_capture_key_pressed = 0;
 
     screen->req.x = params->window_x;
@@ -415,23 +401,13 @@ sc_screen_init(struct sc_screen *screen,
     screen->req.fullscreen = params->fullscreen;
     screen->req.start_fps_counter = params->start_fps_counter;
 
-    static const struct sc_video_buffer_callbacks cbs = {
-        .on_new_frame = sc_video_buffer_on_new_frame,
-    };
-
-    bool ok = sc_video_buffer_init(&screen->vb, params->buffering_time, &cbs,
-                                   screen);
+    bool ok = sc_frame_buffer_init(&screen->fb);
     if (!ok) {
         return false;
     }
 
-    ok = sc_video_buffer_start(&screen->vb);
-    if (!ok) {
-        goto error_destroy_video_buffer;
-    }
-
     if (!sc_fps_counter_init(&screen->fps_counter)) {
-        goto error_stop_and_join_video_buffer;
+        goto error_destroy_frame_buffer;
     }
 
     screen->frame_size = params->frame_size;
@@ -563,11 +539,8 @@ error_destroy_window:
     SDL_DestroyWindow(screen->window);
 error_destroy_fps_counter:
     sc_fps_counter_destroy(&screen->fps_counter);
-error_stop_and_join_video_buffer:
-    sc_video_buffer_stop(&screen->vb);
-    sc_video_buffer_join(&screen->vb);
-error_destroy_video_buffer:
-    sc_video_buffer_destroy(&screen->vb);
+error_destroy_frame_buffer:
+    sc_frame_buffer_destroy(&screen->fb);
 
     return false;
 }
@@ -604,13 +577,11 @@ sc_screen_hide_window(struct sc_screen *screen) {
 
 void
 sc_screen_interrupt(struct sc_screen *screen) {
-    sc_video_buffer_stop(&screen->vb);
     sc_fps_counter_interrupt(&screen->fps_counter);
 }
 
 void
 sc_screen_join(struct sc_screen *screen) {
-    sc_video_buffer_join(&screen->vb);
     sc_fps_counter_join(&screen->fps_counter);
 }
 
@@ -624,7 +595,7 @@ sc_screen_destroy(struct sc_screen *screen) {
     SDL_DestroyRenderer(screen->renderer);
     SDL_DestroyWindow(screen->window);
     sc_fps_counter_destroy(&screen->fps_counter);
-    sc_video_buffer_destroy(&screen->vb);
+    sc_frame_buffer_destroy(&screen->fb);
 }
 
 static void
@@ -730,7 +701,7 @@ update_texture(struct sc_screen *screen, const AVFrame *frame) {
 static bool
 sc_screen_update_frame(struct sc_screen *screen) {
     av_frame_unref(screen->frame);
-    sc_video_buffer_consume(&screen->vb, screen->frame);
+    sc_frame_buffer_consume(&screen->fb, screen->frame);
     AVFrame *frame = screen->frame;
 
     sc_fps_counter_add_rendered_frame(&screen->fps_counter);

app/src/screen.h

@@ -10,12 +10,12 @@
 #include "controller.h"
 #include "coords.h"
 #include "fps_counter.h"
+#include "frame_buffer.h"
 #include "input_manager.h"
 #include "opengl.h"
 #include "trait/key_processor.h"
 #include "trait/frame_sink.h"
 #include "trait/mouse_processor.h"
-#include "video_buffer.h"
 
 struct sc_screen {
     struct sc_frame_sink frame_sink; // frame sink trait
@@ -25,7 +25,7 @@ struct sc_screen {
 #endif
 
     struct sc_input_manager im;
-    struct sc_video_buffer vb;
+    struct sc_frame_buffer fb;
     struct sc_fps_counter fps_counter;
 
     // The initial requested window properties
@@ -59,8 +59,6 @@ struct sc_screen {
     bool maximized;
     bool mipmaps;
 
-    bool event_failed; // in case SDL_PushEvent() returned an error
-
     // To enable/disable mouse capture, a mouse capture key (LALT, LGUI or
     // RGUI) must be pressed. This variable tracks the pressed capture key.
     SDL_Keycode mouse_capture_key_pressed;
@@ -95,8 +93,6 @@ struct sc_screen_params {
 
     bool fullscreen;
     bool start_fps_counter;
-
-    sc_tick buffering_time;
 };
 
 // initialize screen, create window, renderer and texture (window is hidden)

app/src/server.c

@@ -752,6 +752,11 @@ sc_server_configure_tcpip_unknown_address(struct sc_server *server,
     if (is_already_tcpip) {
         // Nothing to do
         LOGI("Device already connected via TCP/IP: %s", serial);
+        server->serial = strdup(serial);
+        if (!server->serial) {
+            LOG_OOM();
+            return false;
+        }
         return true;
     }
 

app/src/trait/frame_source.c

@@ -0,0 +1,59 @@
+#include "frame_source.h"
+
+void
+sc_frame_source_init(struct sc_frame_source *source) {
+    source->sink_count = 0;
+}
+
+void
+sc_frame_source_add_sink(struct sc_frame_source *source,
+                         struct sc_frame_sink *sink) {
+    assert(source->sink_count < SC_FRAME_SOURCE_MAX_SINKS);
+    assert(sink);
+    assert(sink->ops);
+    source->sinks[source->sink_count++] = sink;
+}
+
+static void
+sc_frame_source_sinks_close_firsts(struct sc_frame_source *source,
+                                    unsigned count) {
+    while (count) {
+        struct sc_frame_sink *sink = source->sinks[--count];
+        sink->ops->close(sink);
+    }
+}
+
+bool
+sc_frame_source_sinks_open(struct sc_frame_source *source,
+                           const AVCodecContext *ctx) {
+    assert(source->sink_count);
+    for (unsigned i = 0; i < source->sink_count; ++i) {
+        struct sc_frame_sink *sink = source->sinks[i];
+        if (!sink->ops->open(sink, ctx)) {
+            sc_frame_source_sinks_close_firsts(source, i);
+            return false;
+        }
+    }
+
+    return true;
+}
+
+void
+sc_frame_source_sinks_close(struct sc_frame_source *source) {
+    assert(source->sink_count);
+    sc_frame_source_sinks_close_firsts(source, source->sink_count);
+}
+
+bool
+sc_frame_source_sinks_push(struct sc_frame_source *source,
+                            const AVFrame *frame) {
+    assert(source->sink_count);
+    for (unsigned i = 0; i < source->sink_count; ++i) {
+        struct sc_frame_sink *sink = source->sinks[i];
+        if (!sink->ops->push(sink, frame)) {
+            return false;
+        }
+    }
+
+    return true;
+}

app/src/trait/frame_source.h

@@ -0,0 +1,38 @@
+#ifndef SC_FRAME_SOURCE_H
+#define SC_FRAME_SOURCE_H
+
+#include "common.h"
+
+#include "frame_sink.h"
+
+#define SC_FRAME_SOURCE_MAX_SINKS 2
+
+/**
+ * Frame source trait
+ *
+ * Component able to send AVFrames should implement this trait.
+ */
+struct sc_frame_source {
+    struct sc_frame_sink *sinks[SC_FRAME_SOURCE_MAX_SINKS];
+    unsigned sink_count;
+};
+
+void
+sc_frame_source_init(struct sc_frame_source *source);
+
+void
+sc_frame_source_add_sink(struct sc_frame_source *source,
+                         struct sc_frame_sink *sink);
+
+bool
+sc_frame_source_sinks_open(struct sc_frame_source *source,
+                           const AVCodecContext *ctx);
+
+void
+sc_frame_source_sinks_close(struct sc_frame_source *source);
+
+bool
+sc_frame_source_sinks_push(struct sc_frame_source *source,
+                           const AVFrame *frame);
+
+#endif

app/src/trait/packet_source.c

@@ -0,0 +1,70 @@
+#include "packet_source.h"
+
+void
+sc_packet_source_init(struct sc_packet_source *source) {
+    source->sink_count = 0;
+}
+
+void
+sc_packet_source_add_sink(struct sc_packet_source *source,
+                          struct sc_packet_sink *sink) {
+    assert(source->sink_count < SC_PACKET_SOURCE_MAX_SINKS);
+    assert(sink);
+    assert(sink->ops);
+    source->sinks[source->sink_count++] = sink;
+}
+
+static void
+sc_packet_source_sinks_close_firsts(struct sc_packet_source *source,
+                                    unsigned count) {
+    while (count) {
+        struct sc_packet_sink *sink = source->sinks[--count];
+        sink->ops->close(sink);
+    }
+}
+
+bool
+sc_packet_source_sinks_open(struct sc_packet_source *source,
+                            const AVCodec *codec) {
+    assert(source->sink_count);
+    for (unsigned i = 0; i < source->sink_count; ++i) {
+        struct sc_packet_sink *sink = source->sinks[i];
+        if (!sink->ops->open(sink, codec)) {
+            sc_packet_source_sinks_close_firsts(source, i);
+            return false;
+        }
+    }
+
+    return true;
+}
+
+void
+sc_packet_source_sinks_close(struct sc_packet_source *source) {
+    assert(source->sink_count);
+    sc_packet_source_sinks_close_firsts(source, source->sink_count);
+}
+
+bool
+sc_packet_source_sinks_push(struct sc_packet_source *source,
+                            const AVPacket *packet) {
+    assert(source->sink_count);
+    for (unsigned i = 0; i < source->sink_count; ++i) {
+        struct sc_packet_sink *sink = source->sinks[i];
+        if (!sink->ops->push(sink, packet)) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+void
+sc_packet_source_sinks_disable(struct sc_packet_source *source) {
+    assert(source->sink_count);
+    for (unsigned i = 0; i < source->sink_count; ++i) {
+        struct sc_packet_sink *sink = source->sinks[i];
+        if (sink->ops->disable) {
+            sink->ops->disable(sink);
+        }
+    }
+}

app/src/trait/packet_source.h

@@ -0,0 +1,41 @@
+#ifndef SC_PACKET_SOURCE_H
+#define SC_PACKET_SOURCE_H
+
+#include "common.h"
+
+#include "packet_sink.h"
+
+#define SC_PACKET_SOURCE_MAX_SINKS 2
+
+/**
+ * Packet source trait
+ *
+ * Component able to send AVPackets should implement this trait.
+ */
+struct sc_packet_source {
+    struct sc_packet_sink *sinks[SC_PACKET_SOURCE_MAX_SINKS];
+    unsigned sink_count;
+};
+
+void
+sc_packet_source_init(struct sc_packet_source *source);
+
+void
+sc_packet_source_add_sink(struct sc_packet_source *source,
+                          struct sc_packet_sink *sink);
+
+bool
+sc_packet_source_sinks_open(struct sc_packet_source *source,
+                            const AVCodec *codec);
+
+void
+sc_packet_source_sinks_close(struct sc_packet_source *source);
+
+bool
+sc_packet_source_sinks_push(struct sc_packet_source *source,
+                            const AVPacket *packet);
+
+void
+sc_packet_source_sinks_disable(struct sc_packet_source *source);
+
+#endif

app/src/usb/aoa_hid.c

@@ -14,6 +14,8 @@
 
 #define DEFAULT_TIMEOUT 1000
 
+#define SC_HID_EVENT_QUEUE_MAX 64
+
 static void
 sc_hid_event_log(const struct sc_hid_event *event) {
     // HID Event: [00] FF FF FF FF...
@@ -48,14 +50,20 @@ sc_hid_event_destroy(struct sc_hid_event *hid_event) {
 bool
 sc_aoa_init(struct sc_aoa *aoa, struct sc_usb *usb,
             struct sc_acksync *acksync) {
-    cbuf_init(&aoa->queue);
+    sc_vecdeque_init(&aoa->queue);
+
+    if (!sc_vecdeque_reserve(&aoa->queue, SC_HID_EVENT_QUEUE_MAX)) {
+        return false;
+    }
 
     if (!sc_mutex_init(&aoa->mutex)) {
+        sc_vecdeque_destroy(&aoa->queue);
         return false;
     }
 
     if (!sc_cond_init(&aoa->event_cond)) {
         sc_mutex_destroy(&aoa->mutex);
+        sc_vecdeque_destroy(&aoa->queue);
         return false;
     }
 
@@ -69,9 +77,10 @@ sc_aoa_init(struct sc_aoa *aoa, struct sc_usb *usb,
 void
 sc_aoa_destroy(struct sc_aoa *aoa) {
     // Destroy remaining events
-    struct sc_hid_event event;
-    while (cbuf_take(&aoa->queue, &event)) {
-        sc_hid_event_destroy(&event);
+    while (!sc_vecdeque_is_empty(&aoa->queue)) {
+        struct sc_hid_event *event = sc_vecdeque_popref(&aoa->queue);
+        assert(event);
+        sc_hid_event_destroy(event);
     }
 
     sc_cond_destroy(&aoa->event_cond);
@@ -212,13 +221,19 @@ sc_aoa_push_hid_event(struct sc_aoa *aoa, const struct sc_hid_event *event) {
     }
 
     sc_mutex_lock(&aoa->mutex);
-    bool was_empty = cbuf_is_empty(&aoa->queue);
-    bool res = cbuf_push(&aoa->queue, *event);
-    if (was_empty) {
-        sc_cond_signal(&aoa->event_cond);
+    bool full = sc_vecdeque_is_full(&aoa->queue);
+    if (!full) {
+        bool was_empty = sc_vecdeque_is_empty(&aoa->queue);
+        sc_vecdeque_push_noresize(&aoa->queue, *event);
+        if (was_empty) {
+            sc_cond_signal(&aoa->event_cond);
+        }
     }
+    // Otherwise (if the queue is full), the event is discarded
+
     sc_mutex_unlock(&aoa->mutex);
-    return res;
+
+    return !full;
 }
 
 static int
@@ -227,7 +242,7 @@ run_aoa_thread(void *data) {
 
     for (;;) {
         sc_mutex_lock(&aoa->mutex);
-        while (!aoa->stopped && cbuf_is_empty(&aoa->queue)) {
+        while (!aoa->stopped && sc_vecdeque_is_empty(&aoa->queue)) {
             sc_cond_wait(&aoa->event_cond, &aoa->mutex);
         }
         if (aoa->stopped) {
@@ -235,11 +250,9 @@ run_aoa_thread(void *data) {
             sc_mutex_unlock(&aoa->mutex);
             break;
         }
-        struct sc_hid_event event;
-        bool non_empty = cbuf_take(&aoa->queue, &event);
-        assert(non_empty);
-        (void) non_empty;
 
+        assert(!sc_vecdeque_is_empty(&aoa->queue));
+        struct sc_hid_event event = sc_vecdeque_pop(&aoa->queue);
         uint64_t ack_to_wait = event.ack_to_wait;
         sc_mutex_unlock(&aoa->mutex);
 

app/src/usb/aoa_hid.h

@@ -8,9 +8,9 @@
 
 #include "usb.h"
 #include "util/acksync.h"
-#include "util/cbuf.h"
 #include "util/thread.h"
 #include "util/tick.h"
+#include "util/vecdeque.h"
 
 struct sc_hid_event {
     uint16_t accessory_id;
@@ -27,7 +27,7 @@ sc_hid_event_init(struct sc_hid_event *hid_event, uint16_t accessory_id,
 void
 sc_hid_event_destroy(struct sc_hid_event *hid_event);
 
-struct sc_hid_event_queue CBUF(struct sc_hid_event, 64);
+struct sc_hid_event_queue SC_VECDEQUE(struct sc_hid_event);
 
 struct sc_aoa {
     struct sc_usb *usb;

app/src/util/average.c

@@ -19,8 +19,8 @@ sc_average_push(struct sc_average *avg, float value) {
     avg->avg = ((avg->count - 1) * avg->avg + value) / avg->count;
 }
 
-bool
-sc_average_get(struct sc_average *avg, float *value) {
-    *value = avg->avg;
-    return avg->count;
+float
+sc_average_get(struct sc_average *avg) {
+    assert(avg->count);
+    return avg->avg;
 }

app/src/util/average.h

@@ -22,15 +22,19 @@ struct sc_average {
 void
 sc_average_init(struct sc_average *avg, unsigned range);
 
-/* Push a new value to update the "rolling" average */
+/**
+ * Push a new value to update the "rolling" average
+ */
 void
 sc_average_push(struct sc_average *avg, float value);
 
-/* Get the current average value (if available)
+/**
+ * Get the current average value
  *
- * An average is available if sc_average_push() has been called at least once.
+ * It is an error to call this function if sc_average_push() has not been
+ * called at least once.
  */
-bool
-sc_average_get(struct sc_average *avg, float *value);
+float
+sc_average_get(struct sc_average *avg);
 
 #endif

app/src/util/bytebuf.c

@@ -31,7 +31,7 @@ sc_bytebuf_destroy(struct sc_bytebuf *buf) {
 void
 sc_bytebuf_read(struct sc_bytebuf *buf, uint8_t *to, size_t len) {
     assert(len);
-    assert(sc_bytebuf_read_remaining(buf) >= len);
+    assert(len <= sc_bytebuf_read_available(buf));
     assert(buf->tail != buf->head); // the buffer could not be empty
 
     size_t right_limit = buf->tail < buf->head ? buf->head : buf->alloc_size;
@@ -51,42 +51,40 @@ sc_bytebuf_read(struct sc_bytebuf *buf, uint8_t *to, size_t len) {
 void
 sc_bytebuf_skip(struct sc_bytebuf *buf, size_t len) {
     assert(len);
-    assert(sc_bytebuf_read_remaining(buf) >= len);
+    assert(len <= sc_bytebuf_read_available(buf));
     assert(buf->tail != buf->head); // the buffer could not be empty
 
     buf->tail = (buf->tail + len) % buf->alloc_size;
 }
 
-void
-sc_bytebuf_write(struct sc_bytebuf *buf, const uint8_t *from, size_t len) {
-    assert(len);
-
-    size_t max_len = buf->alloc_size - 1;
-    if (len >= max_len) {
-        // Copy only the right-most bytes
-        memcpy(buf->data, from + len - max_len, max_len);
-        buf->tail = 0;
-        buf->head = max_len;
-        return;
-    }
-
-    size_t right_limit = buf->head < buf->tail ? buf->tail : buf->alloc_size;
-    size_t right_len = right_limit - buf->head;
+static inline void
+sc_bytebuf_write_step0(struct sc_bytebuf *buf, const uint8_t *from,
+                       size_t len) {
+    size_t right_len = buf->alloc_size - buf->head;
     if (len < right_len) {
         right_len = len;
     }
+
     memcpy(buf->data + buf->head, from, right_len);
     if (len > right_len) {
         memcpy(buf->data, from + right_len, len - right_len);
     }
+}
 
-    size_t empty_space = sc_bytebuf_write_remaining(buf);
-    if (len > empty_space) {
-        buf->tail = (buf->tail + len - empty_space) % buf->alloc_size;
-    }
+static inline void
+sc_bytebuf_write_step1(struct sc_bytebuf *buf, size_t len) {
     buf->head = (buf->head + len) % buf->alloc_size;
 }
 
+void
+sc_bytebuf_write(struct sc_bytebuf *buf, const uint8_t *from, size_t len) {
+    assert(len);
+    assert(len <= sc_bytebuf_write_available(buf));
+
+    sc_bytebuf_write_step0(buf, from, len);
+    sc_bytebuf_write_step1(buf, len);
+}
+
 void
 sc_bytebuf_prepare_write(struct sc_bytebuf *buf, const uint8_t *from,
                          size_t len) {
@@ -97,20 +95,11 @@ sc_bytebuf_prepare_write(struct sc_bytebuf *buf, const uint8_t *from,
     // be called with lock held).
 
     assert(len < buf->alloc_size - 1);
-
-    size_t right_len = buf->alloc_size - buf->head;
-    if (len < right_len) {
-        right_len = len;
-    }
-
-    memcpy(buf->data + buf->head, from, right_len);
-    if (len > right_len) {
-        memcpy(buf->data, from + right_len, len - right_len);
-    }
+    sc_bytebuf_write_step0(buf, from, len);
 }
 
 void
 sc_bytebuf_commit_write(struct sc_bytebuf *buf, size_t len) {
-    assert(len <= sc_bytebuf_write_remaining(buf));
-    buf->head = (buf->head + len) % buf->alloc_size;
+    assert(len <= sc_bytebuf_write_available(buf));
+    sc_bytebuf_write_step1(buf, len);
 }

app/src/util/bytebuf.h

@@ -11,8 +11,8 @@ struct sc_bytebuf {
     // The actual capacity is (allocated - 1) so that head == tail is
     // non-ambiguous
     size_t alloc_size;
-    size_t head;
-    size_t tail;
+    size_t head; // writter cursor
+    size_t tail; // reader cursor
     // empty: tail == head
     // full: (tail + 1) % allocated == head
 };
@@ -23,10 +23,10 @@ sc_bytebuf_init(struct sc_bytebuf *buf, size_t alloc_size);
 /**
  * Copy from the bytebuf to a user-provided array
  *
- * The caller must check that len <= buf->len (it is an error to attempt to read
- * more bytes than available).
+ * The caller must check that len <= sc_bytebuf_read_available() (it is an
+ * error to attempt to read more bytes than available).
  *
- * This function is guaranteed to not change the head.
+ * This function is guaranteed not to write to buf->head.
  */
 void
 sc_bytebuf_read(struct sc_bytebuf *buf, uint8_t *to, size_t len);
@@ -34,8 +34,10 @@ sc_bytebuf_read(struct sc_bytebuf *buf, uint8_t *to, size_t len);
 /**
  * Drop len bytes from the buffer
  *
- * The caller must check that len <= buf->len (it is an error to attempt to skip
- * more bytes than available).
+ * The caller must check that len <= sc_bytebuf_read_available() (it is an
+ * error to attempt to skip more bytes than available).
+ *
+ * This function is guaranteed not to change the head.
  *
  * This function is guaranteed to not change the head.
  *
@@ -48,9 +50,10 @@ sc_bytebuf_skip(struct sc_bytebuf *buf, size_t len);
 /**
  * Copy the user-provided array to the bytebuf
  *
- * The length of the input array is not restricted:
- * if len >= sc_bytebuf_write_remaining(buf), then the excessive input bytes
- * will overwrite the oldest bytes in the buffer.
+ * The caller must check that len <= sc_bytebuf_write_available() (it is an
+ * error to write more bytes than the remaining available space).
+ *
+ * This function is guaranteed not to write to buf->tail.
  */
 void
 sc_bytebuf_write(struct sc_bytebuf *buf, const uint8_t *from, size_t len);
@@ -58,14 +61,16 @@ sc_bytebuf_write(struct sc_bytebuf *buf, const uint8_t *from, size_t len);
 /**
  * Copy the user-provided array to the bytebuf, but do not advance the cursor
  *
- * The caller must check that len <= buf->len (it is an error to attempt to
- * write more bytes than available).
+ * The caller must check that len <= sc_bytebuf_write_available() (it is an
+ * error to write more bytes than the remaining available space).
  *
  * After this function is called, the write must be committed with
  * sc_bytebuf_commit_write().
  *
  * The purpose of this mechanism is to acquire a lock only to commit the write,
  * but not to perform the actual copy.
+ *
+ * This function is guaranteed not to access buf->tail.
  */
 void
 sc_bytebuf_prepare_write(struct sc_bytebuf *buf, const uint8_t *from,
@@ -83,21 +88,28 @@ sc_bytebuf_commit_write(struct sc_bytebuf *buf, size_t len);
  * It is an error to read more bytes than available.
  */
 static inline size_t
-sc_bytebuf_read_remaining(struct sc_bytebuf *buf) {
+sc_bytebuf_read_available(struct sc_bytebuf *buf) {
     return (buf->alloc_size + buf->head - buf->tail) % buf->alloc_size;
 }
 
 /**
- * Return the number of bytes which can be written without overwriting
+ * Return the number of bytes which can be written
  *
- * It is not an error to write more bytes than the available space, but this
- * would overwrite the oldest bytes in the buffer.
+ * It is an error to write more bytes than available.
  */
 static inline size_t
-sc_bytebuf_write_remaining(struct sc_bytebuf *buf) {
+sc_bytebuf_write_available(struct sc_bytebuf *buf) {
     return (buf->alloc_size + buf->tail - buf->head - 1) % buf->alloc_size;
 }
 
+/**
+ * Return the actual capacity of the buffer (read available + write available)
+ */
+static inline size_t
+sc_bytebuf_capacity(struct sc_bytebuf *buf) {
+    return buf->alloc_size - 1;
+}
+
 void
 sc_bytebuf_destroy(struct sc_bytebuf *buf);
 

app/src/util/cbuf.h

@@ -1,52 +0,0 @@
-// generic circular buffer (bounded queue) implementation
-#ifndef SC_CBUF_H
-#define SC_CBUF_H
-
-#include "common.h"
-
-#include <stdbool.h>
-#include <unistd.h>
-
-// To define a circular buffer type of 20 ints:
-//     struct cbuf_int CBUF(int, 20);
-//
-// data has length CAP + 1 to distinguish empty vs full.
-#define CBUF(TYPE, CAP) { \
-    TYPE data[(CAP) + 1]; \
-    size_t head; \
-    size_t tail; \
-}
-
-#define cbuf_size_(PCBUF) \
-    (sizeof((PCBUF)->data) / sizeof(*(PCBUF)->data))
-
-#define cbuf_is_empty(PCBUF) \
-    ((PCBUF)->head == (PCBUF)->tail)
-
-#define cbuf_is_full(PCBUF) \
-    (((PCBUF)->head + 1) % cbuf_size_(PCBUF) == (PCBUF)->tail)
-
-#define cbuf_init(PCBUF) \
-    (void) ((PCBUF)->head = (PCBUF)->tail = 0)
-
-#define cbuf_push(PCBUF, ITEM) \
-    ({ \
-        bool ok = !cbuf_is_full(PCBUF); \
-        if (ok) { \
-            (PCBUF)->data[(PCBUF)->head] = (ITEM); \
-            (PCBUF)->head = ((PCBUF)->head + 1) % cbuf_size_(PCBUF); \
-        } \
-        ok; \
-    })
-
-#define cbuf_take(PCBUF, PITEM) \
-    ({ \
-        bool ok = !cbuf_is_empty(PCBUF); \
-        if (ok) { \
-            *(PITEM) = (PCBUF)->data[(PCBUF)->tail]; \
-            (PCBUF)->tail = ((PCBUF)->tail + 1) % cbuf_size_(PCBUF); \
-        } \
-        ok; \
-    })
-
-#endif

app/src/util/memory.c

@@ -0,0 +1,14 @@
+#include "memory.h"
+
+#include <stdlib.h>
+#include <errno.h>
+
+void *
+sc_allocarray(size_t nmemb, size_t size) {
+    size_t bytes;
+    if (__builtin_mul_overflow(nmemb, size, &bytes)) {
+      errno = ENOMEM;
+      return NULL;
+    }
+    return malloc(bytes);
+}

app/src/util/memory.h

@@ -0,0 +1,12 @@
+#ifndef SC_MEMORY_H
+#define SC_MEMORY_H
+
+#include <stddef.h>
+
+/* Like calloc(), but without initialization.
+ * Like reallocarray(), but without reallocation.
+ */
+void *
+sc_allocarray(size_t nmemb, size_t size);
+
+#endif

app/src/util/queue.h

@@ -1,77 +0,0 @@
-// generic intrusive FIFO queue
-#ifndef SC_QUEUE_H
-#define SC_QUEUE_H
-
-#include "common.h"
-
-#include <assert.h>
-#include <stdbool.h>
-#include <stddef.h>
-
-// To define a queue type of "struct foo":
-//    struct queue_foo QUEUE(struct foo);
-#define SC_QUEUE(TYPE) { \
-    TYPE *first; \
-    TYPE *last; \
-}
-
-#define sc_queue_init(PQ) \
-    (void) ((PQ)->first = (PQ)->last = NULL)
-
-#define sc_queue_is_empty(PQ) \
-    !(PQ)->first
-
-// NEXTFIELD is the field in the ITEM type used for intrusive linked-list
-//
-// For example:
-//    struct foo {
-//        int value;
-//        struct foo *next;
-//    };
-//
-//    // define the type "struct my_queue"
-//    struct my_queue SC_QUEUE(struct foo);
-//
-//    struct my_queue queue;
-//    sc_queue_init(&queue);
-//
-//    struct foo v1 = { .value = 42 };
-//    struct foo v2 = { .value = 27 };
-//
-//    sc_queue_push(&queue, next, v1);
-//    sc_queue_push(&queue, next, v2);
-//
-//    struct foo *foo;
-//    sc_queue_take(&queue, next, &foo);
-//    assert(foo->value == 42);
-//    sc_queue_take(&queue, next, &foo);
-//    assert(foo->value == 27);
-//    assert(sc_queue_is_empty(&queue));
-//
-
-// push a new item into the queue
-#define sc_queue_push(PQ, NEXTFIELD, ITEM) \
-    (void) ({ \
-        (ITEM)->NEXTFIELD = NULL; \
-        if (sc_queue_is_empty(PQ)) { \
-            (PQ)->first = (PQ)->last = (ITEM); \
-        } else { \
-            (PQ)->last->NEXTFIELD = (ITEM); \
-            (PQ)->last = (ITEM); \
-        } \
-    })
-
-// take the next item and remove it from the queue (the queue must not be empty)
-// the result is stored in *(PITEM)
-// (without typeof(), we could not store a local variable having the correct
-// type so that we can "return" it)
-#define sc_queue_take(PQ, NEXTFIELD, PITEM) \
-    (void) ({ \
-        assert(!sc_queue_is_empty(PQ)); \
-        *(PITEM) = (PQ)->first; \
-        (PQ)->first = (PQ)->first->NEXTFIELD; \
-    })
-    // no need to update (PQ)->last if the queue is left empty:
-    // (PQ)->last is undefined if !(PQ)->first anyway
-
-#endif

app/src/util/vecdeque.h

@@ -0,0 +1,379 @@
+#ifndef SC_VECDEQUE_H
+#define SC_VECDEQUE_H
+
+#include "common.h"
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "util/memory.h"
+
+/**
+ * A double-ended queue implemented with a growable ring buffer.
+ *
+ * Inspired from the Rust VecDeque type:
+ * <https://doc.rust-lang.org/std/collections/struct.VecDeque.html>
+ */
+
+/**
+ * VecDeque struct body
+ *
+ * A VecDeque is a dynamic ring-buffer, managed by the sc_vecdeque_* helpers.
+ *
+ * It is generic over the type of its items, so it is implemented via macros.
+ *
+ * To use a VecDeque, a new type must be defined:
+ *
+ *     struct vecdeque_int SC_VECDEQUE(int);
+ *
+ * The struct may be anonymous:
+ *
+ *     struct SC_VECDEQUE(const char *) names;
+ *
+ * Functions and macros having name ending with '_' are private.
+ */
+#define SC_VECDEQUE(type) { \
+    size_t cap; \
+    size_t origin; \
+    size_t size; \
+    type *data; \
+}
+
+/**
+ * Static initializer for a VecDeque
+ */
+#define SC_VECDEQUE_INITIALIZER { 0, 0, 0, NULL }
+
+/**
+ * Initialize an empty VecDeque
+ */
+#define sc_vecdeque_init(pv) \
+({ \
+    (pv)->data = NULL; \
+    (pv)->cap = 0; \
+    (pv)->origin = 0; \
+    (pv)->size = 0; \
+})
+
+/**
+ * Destroy a VecDeque
+ */
+#define sc_vecdeque_destroy(pv) \
+    free((pv)->data)
+
+/**
+ * Clear a VecDeque
+ *
+ * Remove all items.
+ */
+#define sc_vecdeque_clear(pv) \
+(void) ({ \
+    sc_vecdeque_destroy(pv); \
+    sc_vecdeque_init(pv); \
+})
+
+/**
+ * Returns the content size
+ */
+#define sc_vecdeque_size(pv) \
+    (pv)->size
+
+/**
+ * Return whether the VecDeque is empty (i.e. its size is 0)
+ */
+#define sc_vecdeque_is_empty(pv) \
+    ((pv)->size == 0)
+
+/**
+ * Return whether the VecDeque is full
+ *
+ * A VecDeque is full when its size equals its current capacity. However, it
+ * does not prevent to push a new item (with sc_vecdeque_push()), since this
+ * will increase its capacity.
+ */
+#define sc_vecdeque_is_full(pv) \
+    ((pv)->size == (pv)->cap)
+
+/**
+ * The minimal allocation size, in number of items
+ *
+ * Private.
+ */
+#define SC_VECDEQUE_MINCAP_ ((size_t) 10)
+
+/**
+ * The maximal allocation size, in number of items
+ *
+ * Use SIZE_MAX/2 to fit in ssize_t, and so that cap*1.5 does not overflow.
+ *
+ * Private.
+ */
+#define sc_vecdeque_max_cap_(pv) (SIZE_MAX / 2 / sizeof(*(pv)->data))
+
+/**
+ * Realloc the internal array to a specific capacity
+ *
+ * On reallocation success, update the VecDeque capacity (`*pcap`) and origin
+ * (`*porigin`), and return the reallocated data.
+ *
+ * On reallocation failure, return NULL without any change.
+ *
+ * Private.
+ *
+ * \param ptr the current `data` field of the SC_VECDEQUE to realloc
+ * \param newcap the requested capacity, in number of items
+ * \param item_size the size of one item (the generic type is unknown from this
+ *                  function)
+ * \param pcap a pointer to the `cap` field of the SC_VECDEQUE [IN/OUT]
+ * \param porigin a pointer to pv->origin (will be read and updated)
+ * \param size the `size` field of the SC_VECDEQUE
+ * \return the new array to assign to the `data` field of the SC_VECDEQUE (if
+ *         not NULL)
+ */
+static inline void *
+sc_vecdeque_reallocdata_(void *ptr, size_t newcap, size_t item_size,
+                         size_t *pcap, size_t *porigin, size_t size) {
+
+    size_t oldcap = *pcap;
+    size_t oldorigin = *porigin;
+
+    assert(newcap > oldcap); // Could only grow
+
+    if (oldorigin + size <= oldcap) {
+        // The current content will stay in place, just realloc
+        //
+        // As an example, here is the content of a ring-buffer (oldcap=10)
+        // before the realloc:
+        //
+        //     _ _ 2 3 4 5 6 7 _ _
+        //         ^
+        //         origin
+        //
+        // It is resized (newcap=15), e.g. with sc_vecdeque_reserve():
+        //
+        //     _ _ 2 3 4 5 6 7 _ _ _ _ _ _ _
+        //         ^
+        //         origin
+
+        void *newptr = reallocarray(ptr, newcap, item_size);
+        if (!newptr) {
+            return NULL;
+        }
+
+        *pcap = newcap;
+        return newptr;
+    }
+
+    // Copy the current content to the new array
+    //
+    // As an example, here is the content of a ring-buffer (oldcap=10) before
+    // the realloc:
+    //
+    //     5 6 7 _ _ 0 1 2 3 4
+    //               ^
+    //               origin
+    //
+    // It is resized (newcap=15), e.g. with sc_vecdeque_reserve():
+    //
+    //     0 1 2 3 4 5 6 7 _ _ _ _ _ _ _
+    //     ^
+    //     origin
+
+    assert(size);
+    void *newptr = sc_allocarray(newcap, item_size);
+    if (!newptr) {
+        return NULL;
+    }
+
+    size_t right_len = MIN(size, oldcap - oldorigin);
+    assert(right_len);
+    memcpy(newptr, ptr + (oldorigin * item_size), right_len * item_size);
+
+    if (size > right_len) {
+        memcpy(newptr + (right_len * item_size), ptr,
+               (size - right_len) * item_size);
+    }
+
+    free(ptr);
+
+    *pcap = newcap;
+    *porigin = 0;
+    return newptr;
+}
+
+/**
+ * Macro to realloc the internal data to a new capacity
+ *
+ * Private.
+ *
+ * \retval true on success
+ * \retval false on allocation failure (the VecDeque is left untouched)
+ */
+#define sc_vecdeque_realloc_(pv, newcap) \
+({ \
+    void *p = sc_vecdeque_reallocdata_((pv)->data, newcap, \
+                                       sizeof(*(pv)->data), &(pv)->cap, \
+                                       &(pv)->origin, (pv)->size); \
+    if (p) { \
+        (pv)->data = p; \
+    } \
+    (bool) p; \
+});
+
+static inline size_t
+sc_vecdeque_growsize_(size_t value)
+{
+    /* integer multiplication by 1.5 */
+    return value + (value >> 1);
+}
+
+/**
+ * Increase the capacity of the VecDeque to at least `mincap`
+ *
+ * \param pv a pointer to the VecDeque
+ * \param mincap (`size_t`) the requested capacity
+ * \retval true on success
+ * \retval false on allocation failure (the VecDeque is left untouched)
+ */
+#define sc_vecdeque_reserve(pv, mincap) \
+({ \
+    assert(mincap <= sc_vecdeque_max_cap_(pv)); \
+    bool ok; \
+    /* avoid to allocate tiny arrays (< SC_VECDEQUE_MINCAP_) */ \
+    size_t mincap_ = MAX(mincap, SC_VECDEQUE_MINCAP_); \
+    if (mincap_ <= (pv)->cap) { \
+        /* nothing to do */ \
+        ok = true; \
+    } else if (mincap_ <= sc_vecdeque_max_cap_(pv)) { \
+        /* not too big */ \
+        size_t newsize = sc_vecdeque_growsize_((pv)->cap); \
+        newsize = CLAMP(newsize, mincap_, sc_vecdeque_max_cap_(pv)); \
+        ok = sc_vecdeque_realloc_(pv, newsize); \
+    } else { \
+        ok = false; \
+    } \
+    ok; \
+})
+
+/**
+ * Automatically grow the VecDeque capacity
+ *
+ * Private.
+ *
+ * \retval true on success
+ * \retval false on allocation failure (the VecDeque is left untouched)
+ */
+#define sc_vecdeque_grow_(pv) \
+({ \
+    bool ok; \
+    if ((pv)->cap < sc_vecdeque_max_cap_(pv)) { \
+        size_t newsize = sc_vecdeque_growsize_((pv)->cap); \
+        newsize = CLAMP(newsize, SC_VECDEQUE_MINCAP_, \
+                        sc_vecdeque_max_cap_(pv)); \
+        ok = sc_vecdeque_realloc_(pv, newsize); \
+    } else { \
+        ok = false; \
+    } \
+    ok; \
+})
+
+/**
+ * Grow the VecDeque capacity if it is full
+ *
+ * Private.
+ *
+ * \retval true on success
+ * \retval false on allocation failure (the VecDeque is left untouched)
+ */
+#define sc_vecdeque_grow_if_needed_(pv) \
+    (!sc_vecdeque_is_full(pv) || sc_vecdeque_grow_(pv))
+
+/**
+ * Push an uninitialized item, and return a pointer to it
+ *
+ * It does not attempt to resize the VecDeque. It is an error to this function
+ * if the VecDeque is full.
+ *
+ * This function may not fail. It returns a valid non-NULL pointer to the
+ * uninitialized item just pushed.
+ */
+#define sc_vecdeque_push_hole_noresize(pv) \
+({ \
+    assert(!sc_vecdeque_is_full(pv)); \
+    ++(pv)->size; \
+    &(pv)->data[((pv)->origin + (pv)->size - 1) % (pv)->cap]; \
+})
+
+/**
+ * Push an uninitialized item, and return a pointer to it
+ *
+ * If the VecDeque is full, it is resized.
+ *
+ * This function returns either a valid non-nULL pointer to the uninitialized
+ * item just pushed, or NULL on reallocation failure.
+ */
+#define sc_vecdeque_push_hole(pv) \
+    (sc_vecdeque_grow_if_needed_(pv) ? \
+            sc_vecdeque_push_hole_noresize(pv) : NULL)
+
+/**
+ * Push an item
+ *
+ * It does not attempt to resize the VecDeque. It is an error to this function
+ * if the VecDeque is full.
+ *
+ * This function may not fail.
+ */
+#define sc_vecdeque_push_noresize(pv, item) \
+(void) ({ \
+    assert(!sc_vecdeque_is_full(pv)); \
+    ++(pv)->size; \
+    (pv)->data[((pv)->origin + (pv)->size - 1) % (pv)->cap] = item; \
+})
+
+/**
+ * Push an item
+ *
+ * If the VecDeque is full, it is resized.
+ *
+ * \retval true on success
+ * \retval false on allocation failure (the VecDeque is left untouched)
+ */
+#define sc_vecdeque_push(pv, item) \
+({ \
+    bool ok = sc_vecdeque_grow_if_needed_(pv); \
+    if (ok) { \
+        sc_vecdeque_push_noresize(pv, item); \
+    } \
+    ok; \
+})
+
+/**
+ * Pop an item and return a pointer to it (still in the VecDeque)
+ *
+ * Returning a pointer allows the caller to destroy it in place without copy
+ * (especially if the item type is big).
+ *
+ * It is an error to call this function if the VecDeque is empty.
+ */
+#define sc_vecdeque_popref(pv) \
+({ \
+    assert(!sc_vecdeque_is_empty(pv)); \
+    size_t pos = (pv)->origin; \
+    (pv)->origin = ((pv)->origin + 1) % (pv)->cap; \
+    --(pv)->size; \
+    &(pv)->data[pos]; \
+})
+
+/**
+ * Pop an item and returns it
+ *
+ * It is an error to call this function if the VecDeque is empty.
+ */
+#define sc_vecdeque_pop(pv) \
+    (*sc_vecdeque_popref(pv))
+
+#endif

app/src/util/vector.h

@@ -118,7 +118,7 @@ static inline void *
 sc_vector_reallocdata_(void *ptr, size_t count, size_t size,
                         size_t *restrict pcap, size_t *restrict psize)
 {
-    void *p = realloc(ptr, count * size);
+    void *p = reallocarray(ptr, count, size);
     if (!p) {
         return NULL;
     }

app/src/v4l2_sink.c

@@ -126,7 +126,7 @@ run_v4l2_sink(void *data) {
         vs->has_frame = false;
         sc_mutex_unlock(&vs->mutex);
 
-        sc_video_buffer_consume(&vs->vb, vs->frame);
+        sc_frame_buffer_consume(&vs->fb, vs->frame);
 
         bool ok = encode_and_write_frame(vs, vs->frame);
         av_frame_unref(vs->frame);
@@ -141,42 +141,19 @@ run_v4l2_sink(void *data) {
     return 0;
 }
 
-static void
-sc_video_buffer_on_new_frame(struct sc_video_buffer *vb, bool previous_skipped,
-                             void *userdata) {
-    (void) vb;
-    struct sc_v4l2_sink *vs = userdata;
-
-    if (!previous_skipped) {
-        sc_mutex_lock(&vs->mutex);
-        vs->has_frame = true;
-        sc_cond_signal(&vs->cond);
-        sc_mutex_unlock(&vs->mutex);
-    }
-}
-
 static bool
 sc_v4l2_sink_open(struct sc_v4l2_sink *vs, const AVCodecContext *ctx) {
     assert(ctx->pix_fmt == AV_PIX_FMT_YUV420P);
     (void) ctx;
 
-    static const struct sc_video_buffer_callbacks cbs = {
-        .on_new_frame = sc_video_buffer_on_new_frame,
-    };
-
-    bool ok = sc_video_buffer_init(&vs->vb, vs->buffering_time, &cbs, vs);
+    bool ok = sc_frame_buffer_init(&vs->fb);
     if (!ok) {
         return false;
     }
 
-    ok = sc_video_buffer_start(&vs->vb);
-    if (!ok) {
-        goto error_video_buffer_destroy;
-    }
-
     ok = sc_mutex_init(&vs->mutex);
     if (!ok) {
-        goto error_video_buffer_stop_and_join;
+        goto error_frame_buffer_destroy;
     }
 
     ok = sc_cond_init(&vs->cond);
@@ -301,11 +278,8 @@ error_cond_destroy:
     sc_cond_destroy(&vs->cond);
 error_mutex_destroy:
     sc_mutex_destroy(&vs->mutex);
-error_video_buffer_stop_and_join:
-    sc_video_buffer_stop(&vs->vb);
-    sc_video_buffer_join(&vs->vb);
-error_video_buffer_destroy:
-    sc_video_buffer_destroy(&vs->vb);
+error_frame_buffer_destroy:
+    sc_frame_buffer_destroy(&vs->fb);
 
     return false;
 }
@@ -317,10 +291,7 @@ sc_v4l2_sink_close(struct sc_v4l2_sink *vs) {
     sc_cond_signal(&vs->cond);
     sc_mutex_unlock(&vs->mutex);
 
-    sc_video_buffer_stop(&vs->vb);
-
     sc_thread_join(&vs->thread, NULL);
-    sc_video_buffer_join(&vs->vb);
 
     av_packet_free(&vs->packet);
     av_frame_free(&vs->frame);
@@ -330,12 +301,25 @@ sc_v4l2_sink_close(struct sc_v4l2_sink *vs) {
     avformat_free_context(vs->format_ctx);
     sc_cond_destroy(&vs->cond);
     sc_mutex_destroy(&vs->mutex);
-    sc_video_buffer_destroy(&vs->vb);
+    sc_frame_buffer_destroy(&vs->fb);
 }
 
 static bool
 sc_v4l2_sink_push(struct sc_v4l2_sink *vs, const AVFrame *frame) {
-    return sc_video_buffer_push(&vs->vb, frame);
+    bool previous_skipped;
+    bool ok = sc_frame_buffer_push(&vs->fb, frame, &previous_skipped);
+    if (!ok) {
+        return false;
+    }
+
+    if (!previous_skipped) {
+        sc_mutex_lock(&vs->mutex);
+        vs->has_frame = true;
+        sc_cond_signal(&vs->cond);
+        sc_mutex_unlock(&vs->mutex);
+    }
+
+    return true;
 }
 
 static bool
@@ -358,7 +342,7 @@ sc_v4l2_frame_sink_push(struct sc_frame_sink *sink, const AVFrame *frame) {
 
 bool
 sc_v4l2_sink_init(struct sc_v4l2_sink *vs, const char *device_name,
-                  struct sc_size frame_size, sc_tick buffering_time) {
+                  struct sc_size frame_size) {
     vs->device_name = strdup(device_name);
     if (!vs->device_name) {
         LOGE("Could not strdup v4l2 device name");
@@ -366,7 +350,6 @@ sc_v4l2_sink_init(struct sc_v4l2_sink *vs, const char *device_name,
     }
 
     vs->frame_size = frame_size;
-    vs->buffering_time = buffering_time;
 
     static const struct sc_frame_sink_ops ops = {
         .open = sc_v4l2_frame_sink_open,

app/src/v4l2_sink.h

@@ -8,19 +8,18 @@
 
 #include "coords.h"
 #include "trait/frame_sink.h"
-#include "video_buffer.h"
+#include "frame_buffer.h"
 #include "util/tick.h"
 
 struct sc_v4l2_sink {
     struct sc_frame_sink frame_sink; // frame sink trait
 
-    struct sc_video_buffer vb;
+    struct sc_frame_buffer fb;
     AVFormatContext *format_ctx;
     AVCodecContext *encoder_ctx;
 
     char *device_name;
     struct sc_size frame_size;
-    sc_tick buffering_time;
 
     sc_thread thread;
     sc_mutex mutex;
@@ -35,7 +34,7 @@ struct sc_v4l2_sink {
 
 bool
 sc_v4l2_sink_init(struct sc_v4l2_sink *vs, const char *device_name,
-                  struct sc_size frame_size, sc_tick buffering_time);
+                  struct sc_size frame_size);
 
 void
 sc_v4l2_sink_destroy(struct sc_v4l2_sink *vs);

app/src/video_buffer.c

@@ -1,254 +0,0 @@
-#include "video_buffer.h"
-
-#include <assert.h>
-#include <stdlib.h>
-
-#include <libavutil/avutil.h>
-#include <libavformat/avformat.h>
-
-#include "util/log.h"
-
-#define SC_BUFFERING_NDEBUG // comment to debug
-
-static struct sc_video_buffer_frame *
-sc_video_buffer_frame_new(const AVFrame *frame) {
-    struct sc_video_buffer_frame *vb_frame = malloc(sizeof(*vb_frame));
-    if (!vb_frame) {
-        LOG_OOM();
-        return NULL;
-    }
-
-    vb_frame->frame = av_frame_alloc();
-    if (!vb_frame->frame) {
-        LOG_OOM();
-        free(vb_frame);
-        return NULL;
-    }
-
-    if (av_frame_ref(vb_frame->frame, frame)) {
-        av_frame_free(&vb_frame->frame);
-        free(vb_frame);
-        return NULL;
-    }
-
-    return vb_frame;
-}
-
-static void
-sc_video_buffer_frame_delete(struct sc_video_buffer_frame *vb_frame) {
-    av_frame_unref(vb_frame->frame);
-    av_frame_free(&vb_frame->frame);
-    free(vb_frame);
-}
-
-static bool
-sc_video_buffer_offer(struct sc_video_buffer *vb, const AVFrame *frame) {
-    bool previous_skipped;
-    bool ok = sc_frame_buffer_push(&vb->fb, frame, &previous_skipped);
-    if (!ok) {
-        return false;
-    }
-
-    vb->cbs->on_new_frame(vb, previous_skipped, vb->cbs_userdata);
-    return true;
-}
-
-static int
-run_buffering(void *data) {
-    struct sc_video_buffer *vb = data;
-
-    assert(vb->buffering_time > 0);
-
-    for (;;) {
-        sc_mutex_lock(&vb->b.mutex);
-
-        while (!vb->b.stopped && sc_queue_is_empty(&vb->b.queue)) {
-            sc_cond_wait(&vb->b.queue_cond, &vb->b.mutex);
-        }
-
-        if (vb->b.stopped) {
-            sc_mutex_unlock(&vb->b.mutex);
-            goto stopped;
-        }
-
-        struct sc_video_buffer_frame *vb_frame;
-        sc_queue_take(&vb->b.queue, next, &vb_frame);
-
-        sc_tick max_deadline = sc_tick_now() + vb->buffering_time;
-        // PTS (written by the server) are expressed in microseconds
-        sc_tick pts = SC_TICK_TO_US(vb_frame->frame->pts);
-
-        bool timed_out = false;
-        while (!vb->b.stopped && !timed_out) {
-            sc_tick deadline = sc_clock_to_system_time(&vb->b.clock, pts)
-                             + vb->buffering_time;
-            if (deadline > max_deadline) {
-                deadline = max_deadline;
-            }
-
-            timed_out =
-                !sc_cond_timedwait(&vb->b.wait_cond, &vb->b.mutex, deadline);
-        }
-
-        if (vb->b.stopped) {
-            sc_video_buffer_frame_delete(vb_frame);
-            sc_mutex_unlock(&vb->b.mutex);
-            goto stopped;
-        }
-
-        sc_mutex_unlock(&vb->b.mutex);
-
-#ifndef SC_BUFFERING_NDEBUG
-        LOGD("Buffering: %" PRItick ";%" PRItick ";%" PRItick,
-             pts, vb_frame->push_date, sc_tick_now());
-#endif
-
-        sc_video_buffer_offer(vb, vb_frame->frame);
-
-        sc_video_buffer_frame_delete(vb_frame);
-    }
-
-stopped:
-    // Flush queue
-    while (!sc_queue_is_empty(&vb->b.queue)) {
-        struct sc_video_buffer_frame *vb_frame;
-        sc_queue_take(&vb->b.queue, next, &vb_frame);
-        sc_video_buffer_frame_delete(vb_frame);
-    }
-
-    LOGD("Buffering thread ended");
-
-    return 0;
-}
-
-bool
-sc_video_buffer_init(struct sc_video_buffer *vb, sc_tick buffering_time,
-                     const struct sc_video_buffer_callbacks *cbs,
-                     void *cbs_userdata) {
-    bool ok = sc_frame_buffer_init(&vb->fb);
-    if (!ok) {
-        return false;
-    }
-
-    assert(buffering_time >= 0);
-    if (buffering_time) {
-        ok = sc_mutex_init(&vb->b.mutex);
-        if (!ok) {
-            sc_frame_buffer_destroy(&vb->fb);
-            return false;
-        }
-
-        ok = sc_cond_init(&vb->b.queue_cond);
-        if (!ok) {
-            sc_mutex_destroy(&vb->b.mutex);
-            sc_frame_buffer_destroy(&vb->fb);
-            return false;
-        }
-
-        ok = sc_cond_init(&vb->b.wait_cond);
-        if (!ok) {
-            sc_cond_destroy(&vb->b.queue_cond);
-            sc_mutex_destroy(&vb->b.mutex);
-            sc_frame_buffer_destroy(&vb->fb);
-            return false;
-        }
-
-        sc_clock_init(&vb->b.clock);
-        sc_queue_init(&vb->b.queue);
-    }
-
-    assert(cbs);
-    assert(cbs->on_new_frame);
-
-    vb->buffering_time = buffering_time;
-    vb->cbs = cbs;
-    vb->cbs_userdata = cbs_userdata;
-    return true;
-}
-
-bool
-sc_video_buffer_start(struct sc_video_buffer *vb) {
-    if (vb->buffering_time) {
-        bool ok =
-            sc_thread_create(&vb->b.thread, run_buffering, "scrcpy-vbuf", vb);
-        if (!ok) {
-            LOGE("Could not start buffering thread");
-            return false;
-        }
-    }
-
-    return true;
-}
-
-void
-sc_video_buffer_stop(struct sc_video_buffer *vb) {
-    if (vb->buffering_time) {
-        sc_mutex_lock(&vb->b.mutex);
-        vb->b.stopped = true;
-        sc_cond_signal(&vb->b.queue_cond);
-        sc_cond_signal(&vb->b.wait_cond);
-        sc_mutex_unlock(&vb->b.mutex);
-    }
-}
-
-void
-sc_video_buffer_join(struct sc_video_buffer *vb) {
-    if (vb->buffering_time) {
-        sc_thread_join(&vb->b.thread, NULL);
-    }
-}
-
-void
-sc_video_buffer_destroy(struct sc_video_buffer *vb) {
-    sc_frame_buffer_destroy(&vb->fb);
-    if (vb->buffering_time) {
-        sc_cond_destroy(&vb->b.wait_cond);
-        sc_cond_destroy(&vb->b.queue_cond);
-        sc_mutex_destroy(&vb->b.mutex);
-    }
-}
-
-bool
-sc_video_buffer_push(struct sc_video_buffer *vb, const AVFrame *frame) {
-    if (!vb->buffering_time) {
-        // No buffering
-        return sc_video_buffer_offer(vb, frame);
-    }
-
-    sc_mutex_lock(&vb->b.mutex);
-
-    sc_tick pts = SC_TICK_FROM_US(frame->pts);
-    sc_clock_update(&vb->b.clock, sc_tick_now(), pts);
-    sc_cond_signal(&vb->b.wait_cond);
-
-    if (vb->b.clock.count == 1) {
-        sc_mutex_unlock(&vb->b.mutex);
-        // First frame, offer it immediately, for two reasons:
-        //  - not to delay the opening of the scrcpy window
-        //  - the buffering estimation needs at least two clock points, so it
-        //  could not handle the first frame
-        return sc_video_buffer_offer(vb, frame);
-    }
-
-    struct sc_video_buffer_frame *vb_frame = sc_video_buffer_frame_new(frame);
-    if (!vb_frame) {
-        sc_mutex_unlock(&vb->b.mutex);
-        LOG_OOM();
-        return false;
-    }
-
-#ifndef SC_BUFFERING_NDEBUG
-    vb_frame->push_date = sc_tick_now();
-#endif
-    sc_queue_push(&vb->b.queue, next, vb_frame);
-    sc_cond_signal(&vb->b.queue_cond);
-
-    sc_mutex_unlock(&vb->b.mutex);
-
-    return true;
-}
-
-void
-sc_video_buffer_consume(struct sc_video_buffer *vb, AVFrame *dst) {
-    sc_frame_buffer_consume(&vb->fb, dst);
-}

app/src/video_buffer.h

@@ -1,76 +0,0 @@
-#ifndef SC_VIDEO_BUFFER_H
-#define SC_VIDEO_BUFFER_H
-
-#include "common.h"
-
-#include <stdbool.h>
-
-#include "clock.h"
-#include "frame_buffer.h"
-#include "util/queue.h"
-#include "util/thread.h"
-#include "util/tick.h"
-
-// forward declarations
-typedef struct AVFrame AVFrame;
-
-struct sc_video_buffer_frame {
-    AVFrame *frame;
-    struct sc_video_buffer_frame *next;
-#ifndef NDEBUG
-    sc_tick push_date;
-#endif
-};
-
-struct sc_video_buffer_frame_queue SC_QUEUE(struct sc_video_buffer_frame);
-
-struct sc_video_buffer {
-    struct sc_frame_buffer fb;
-
-    sc_tick buffering_time;
-
-    // only if buffering_time > 0
-    struct {
-        sc_thread thread;
-        sc_mutex mutex;
-        sc_cond queue_cond;
-        sc_cond wait_cond;
-
-        struct sc_clock clock;
-        struct sc_video_buffer_frame_queue queue;
-        bool stopped;
-    } b; // buffering
-
-    const struct sc_video_buffer_callbacks *cbs;
-    void *cbs_userdata;
-};
-
-struct sc_video_buffer_callbacks {
-    void (*on_new_frame)(struct sc_video_buffer *vb, bool previous_skipped,
-                         void *userdata);
-};
-
-bool
-sc_video_buffer_init(struct sc_video_buffer *vb, sc_tick buffering_time,
-                     const struct sc_video_buffer_callbacks *cbs,
-                     void *cbs_userdata);
-
-bool
-sc_video_buffer_start(struct sc_video_buffer *vb);
-
-void
-sc_video_buffer_stop(struct sc_video_buffer *vb);
-
-void
-sc_video_buffer_join(struct sc_video_buffer *vb);
-
-void
-sc_video_buffer_destroy(struct sc_video_buffer *vb);
-
-bool
-sc_video_buffer_push(struct sc_video_buffer *vb, const AVFrame *frame);
-
-void
-sc_video_buffer_consume(struct sc_video_buffer *vb, AVFrame *dst);
-
-#endif

app/tests/test_bytebuf.c

@@ -13,23 +13,23 @@ void test_bytebuf_simple(void) {
     assert(ok);
 
     sc_bytebuf_write(&buf, (uint8_t *) "hello", sizeof("hello") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 5);
+    assert(sc_bytebuf_read_available(&buf) == 5);
 
     sc_bytebuf_read(&buf, data, 4);
     assert(!strncmp((char *) data, "hell", 4));
 
     sc_bytebuf_write(&buf, (uint8_t *) " world", sizeof(" world") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 7);
+    assert(sc_bytebuf_read_available(&buf) == 7);
 
     sc_bytebuf_write(&buf, (uint8_t *) "!", 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 8);
+    assert(sc_bytebuf_read_available(&buf) == 8);
 
     sc_bytebuf_read(&buf, &data[4], 8);
-    assert(sc_bytebuf_read_remaining(&buf) == 0);
+    assert(sc_bytebuf_read_available(&buf) == 0);
 
     data[12] = '\0';
     assert(!strcmp((char *) data, "hello world!"));
-    assert(sc_bytebuf_read_remaining(&buf) == 0);
+    assert(sc_bytebuf_read_available(&buf) == 0);
 
     sc_bytebuf_destroy(&buf);
 }
@@ -42,58 +42,31 @@ void test_bytebuf_boundaries(void) {
     assert(ok);
 
     sc_bytebuf_write(&buf, (uint8_t *) "hello ", sizeof("hello ") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 6);
+    assert(sc_bytebuf_read_available(&buf) == 6);
 
     sc_bytebuf_write(&buf, (uint8_t *) "hello ", sizeof("hello ") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 12);
+    assert(sc_bytebuf_read_available(&buf) == 12);
 
     sc_bytebuf_write(&buf, (uint8_t *) "hello ", sizeof("hello ") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 18);
+    assert(sc_bytebuf_read_available(&buf) == 18);
 
     sc_bytebuf_read(&buf, data, 9);
     assert(!strncmp((char *) data, "hello hel", 9));
-    assert(sc_bytebuf_read_remaining(&buf) == 9);
+    assert(sc_bytebuf_read_available(&buf) == 9);
 
     sc_bytebuf_write(&buf, (uint8_t *) "world", sizeof("world") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 14);
+    assert(sc_bytebuf_read_available(&buf) == 14);
 
     sc_bytebuf_write(&buf, (uint8_t *) "!", 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 15);
+    assert(sc_bytebuf_read_available(&buf) == 15);
 
     sc_bytebuf_skip(&buf, 3);
-    assert(sc_bytebuf_read_remaining(&buf) == 12);
+    assert(sc_bytebuf_read_available(&buf) == 12);
 
     sc_bytebuf_read(&buf, data, 12);
     data[12] = '\0';
     assert(!strcmp((char *) data, "hello world!"));
-    assert(sc_bytebuf_read_remaining(&buf) == 0);
-
-    sc_bytebuf_destroy(&buf);
-}
-
-void test_bytebuf_overwrite(void) {
-    struct sc_bytebuf buf;
-    uint8_t data[10];
-
-    bool ok = sc_bytebuf_init(&buf, 10); // so actual capacity is 9
-    assert(ok);
-
-    sc_bytebuf_write(&buf, (uint8_t *) "hello ", sizeof("hello ") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 6);
-
-    sc_bytebuf_write(&buf, (uint8_t *) "abcdef", sizeof("abcdef") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 9);
-
-    sc_bytebuf_read(&buf, data, 9);
-    assert(!strncmp((char *) data, "lo abcdef", 9));
-
-    sc_bytebuf_write(&buf, (uint8_t *) "a very big buffer",
-                     sizeof("a very big buffer") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 9);
-
-    sc_bytebuf_read(&buf, data, 9);
-    assert(!strncmp((char *) data, "ig buffer", 9));
-    assert(sc_bytebuf_read_remaining(&buf) == 0);
+    assert(sc_bytebuf_read_available(&buf) == 0);
 
     sc_bytebuf_destroy(&buf);
 }
@@ -106,37 +79,37 @@ void test_bytebuf_two_steps_write(void) {
     assert(ok);
 
     sc_bytebuf_write(&buf, (uint8_t *) "hello ", sizeof("hello ") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 6);
+    assert(sc_bytebuf_read_available(&buf) == 6);
 
     sc_bytebuf_write(&buf, (uint8_t *) "hello ", sizeof("hello ") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 12);
+    assert(sc_bytebuf_read_available(&buf) == 12);
 
     sc_bytebuf_prepare_write(&buf, (uint8_t *) "hello ", sizeof("hello ") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 12); // write not committed yet
+    assert(sc_bytebuf_read_available(&buf) == 12); // write not committed yet
 
     sc_bytebuf_read(&buf, data, 9);
     assert(!strncmp((char *) data, "hello hel", 3));
-    assert(sc_bytebuf_read_remaining(&buf) == 3);
+    assert(sc_bytebuf_read_available(&buf) == 3);
 
     sc_bytebuf_commit_write(&buf, sizeof("hello ") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 9);
+    assert(sc_bytebuf_read_available(&buf) == 9);
 
     sc_bytebuf_prepare_write(&buf, (uint8_t *) "world", sizeof("world") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 9); // write not committed yet
+    assert(sc_bytebuf_read_available(&buf) == 9); // write not committed yet
 
     sc_bytebuf_commit_write(&buf, sizeof("world") - 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 14);
+    assert(sc_bytebuf_read_available(&buf) == 14);
 
     sc_bytebuf_write(&buf, (uint8_t *) "!", 1);
-    assert(sc_bytebuf_read_remaining(&buf) == 15);
+    assert(sc_bytebuf_read_available(&buf) == 15);
 
     sc_bytebuf_skip(&buf, 3);
-    assert(sc_bytebuf_read_remaining(&buf) == 12);
+    assert(sc_bytebuf_read_available(&buf) == 12);
 
     sc_bytebuf_read(&buf, data, 12);
     data[12] = '\0';
     assert(!strcmp((char *) data, "hello world!"));
-    assert(sc_bytebuf_read_remaining(&buf) == 0);
+    assert(sc_bytebuf_read_available(&buf) == 0);
 
     sc_bytebuf_destroy(&buf);
 }
@@ -147,7 +120,6 @@ int main(int argc, char *argv[]) {
 
     test_bytebuf_simple();
     test_bytebuf_boundaries();
-    test_bytebuf_overwrite();
     test_bytebuf_two_steps_write();
 
     return 0;

app/tests/test_cbuf.c

@@ -1,78 +0,0 @@
-#include "common.h"
-
-#include <assert.h>
-#include <string.h>
-
-#include "util/cbuf.h"
-
-struct int_queue CBUF(int, 32);
-
-static void test_cbuf_empty(void) {
-    struct int_queue queue;
-    cbuf_init(&queue);
-
-    assert(cbuf_is_empty(&queue));
-
-    bool push_ok = cbuf_push(&queue, 42);
-    assert(push_ok);
-    assert(!cbuf_is_empty(&queue));
-
-    int item;
-    bool take_ok = cbuf_take(&queue, &item);
-    assert(take_ok);
-    assert(cbuf_is_empty(&queue));
-
-    bool take_empty_ok = cbuf_take(&queue, &item);
-    assert(!take_empty_ok); // the queue is empty
-}
-
-static void test_cbuf_full(void) {
-    struct int_queue queue;
-    cbuf_init(&queue);
-
-    assert(!cbuf_is_full(&queue));
-
-    // fill the queue
-    for (int i = 0; i < 32; ++i) {
-        bool ok = cbuf_push(&queue, i);
-        assert(ok);
-    }
-    bool ok = cbuf_push(&queue, 42);
-    assert(!ok); // the queue if full
-
-    int item;
-    bool take_ok = cbuf_take(&queue, &item);
-    assert(take_ok);
-    assert(!cbuf_is_full(&queue));
-}
-
-static void test_cbuf_push_take(void) {
-    struct int_queue queue;
-    cbuf_init(&queue);
-
-    bool push1_ok = cbuf_push(&queue, 42);
-    assert(push1_ok);
-
-    bool push2_ok = cbuf_push(&queue, 35);
-    assert(push2_ok);
-
-    int item;
-
-    bool take1_ok = cbuf_take(&queue, &item);
-    assert(take1_ok);
-    assert(item == 42);
-
-    bool take2_ok = cbuf_take(&queue, &item);
-    assert(take2_ok);
-    assert(item == 35);
-}
-
-int main(int argc, char *argv[]) {
-    (void) argc;
-    (void) argv;
-
-    test_cbuf_empty();
-    test_cbuf_full();
-    test_cbuf_push_take();
-    return 0;
-}

app/tests/test_queue.c

@@ -1,43 +0,0 @@
-#include "common.h"
-
-#include <assert.h>
-
-#include "util/queue.h"
-
-struct foo {
-    int value;
-    struct foo *next;
-};
-
-static void test_queue(void) {
-    struct my_queue SC_QUEUE(struct foo) queue;
-    sc_queue_init(&queue);
-
-    assert(sc_queue_is_empty(&queue));
-
-    struct foo v1 = { .value = 42 };
-    struct foo v2 = { .value = 27 };
-
-    sc_queue_push(&queue, next, &v1);
-    sc_queue_push(&queue, next, &v2);
-
-    struct foo *foo;
-
-    assert(!sc_queue_is_empty(&queue));
-    sc_queue_take(&queue, next, &foo);
-    assert(foo->value == 42);
-
-    assert(!sc_queue_is_empty(&queue));
-    sc_queue_take(&queue, next, &foo);
-    assert(foo->value == 27);
-
-    assert(sc_queue_is_empty(&queue));
-}
-
-int main(int argc, char *argv[]) {
-    (void) argc;
-    (void) argv;
-
-    test_queue();
-    return 0;
-}

app/tests/test_vecdeque.c

@@ -0,0 +1,197 @@
+#include "common.h"
+
+#include <assert.h>
+
+#include "util/vecdeque.h"
+
+#define pr(pv) \
+({ \
+    fprintf(stderr, "cap=%lu origin=%lu size=%lu\n", (pv)->cap, (pv)->origin, (pv)->size); \
+    for (size_t i = 0; i < (pv)->cap; ++i) \
+        fprintf(stderr, "%d ", (pv)->data[i]); \
+    fprintf(stderr, "\n"); \
+})
+
+static void test_vecdeque_push_pop(void) {
+    struct SC_VECDEQUE(int) vdq = SC_VECDEQUE_INITIALIZER;
+
+    assert(sc_vecdeque_is_empty(&vdq));
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    bool ok = sc_vecdeque_push(&vdq, 5);
+    assert(ok);
+    assert(sc_vecdeque_size(&vdq) == 1);
+
+    ok = sc_vecdeque_push(&vdq, 12);
+    assert(ok);
+    assert(sc_vecdeque_size(&vdq) == 2);
+
+    int v = sc_vecdeque_pop(&vdq);
+    assert(v == 5);
+    assert(sc_vecdeque_size(&vdq) == 1);
+
+    ok = sc_vecdeque_push(&vdq, 7);
+    assert(ok);
+    assert(sc_vecdeque_size(&vdq) == 2);
+
+    int *p = sc_vecdeque_popref(&vdq);
+    assert(p);
+    assert(*p == 12);
+    assert(sc_vecdeque_size(&vdq) == 1);
+
+    v = sc_vecdeque_pop(&vdq);
+    assert(v == 7);
+    assert(sc_vecdeque_size(&vdq) == 0);
+    assert(sc_vecdeque_is_empty(&vdq));
+
+    sc_vecdeque_destroy(&vdq);
+}
+
+static void test_vecdeque_reserve(void) {
+    struct SC_VECDEQUE(int) vdq = SC_VECDEQUE_INITIALIZER;
+
+    bool ok = sc_vecdeque_reserve(&vdq, 20);
+    assert(ok);
+    assert(vdq.cap == 20);
+
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    for (size_t i = 0; i < 20; ++i) {
+        ok = sc_vecdeque_push(&vdq, i);
+        assert(ok);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 20);
+
+    // It is now full
+
+    for (int i = 0; i < 5; ++i) {
+        int v = sc_vecdeque_pop(&vdq);
+        assert(v == i);
+    }
+    assert(sc_vecdeque_size(&vdq) == 15);
+
+    for (int i = 20; i < 25; ++i) {
+        ok = sc_vecdeque_push(&vdq, i);
+        assert(ok);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 20);
+    assert(vdq.cap == 20);
+
+    // Now, the content wraps around the ring buffer:
+    // 20 21 22 23 24  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19
+    //                 ^
+    //                 origin
+
+    // It is now full, let's reserve some space
+    ok = sc_vecdeque_reserve(&vdq, 30);
+    assert(ok);
+    assert(vdq.cap == 30);
+
+    assert(sc_vecdeque_size(&vdq) == 20);
+
+    for (int i = 0; i < 20; ++i) {
+        // We should retrieve the items we inserted in order
+        int v = sc_vecdeque_pop(&vdq);
+        assert(v == i + 5);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    sc_vecdeque_destroy(&vdq);
+}
+
+static void test_vecdeque_grow() {
+    struct SC_VECDEQUE(int) vdq = SC_VECDEQUE_INITIALIZER;
+
+    bool ok = sc_vecdeque_reserve(&vdq, 20);
+    assert(ok);
+    assert(vdq.cap == 20);
+
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    for (int i = 0; i < 500; ++i) {
+        ok = sc_vecdeque_push(&vdq, i);
+        assert(ok);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 500);
+
+    for (int i = 0; i < 100; ++i) {
+        int v = sc_vecdeque_pop(&vdq);
+        assert(v == i);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 400);
+
+    for (int i = 500; i < 1000; ++i) {
+        ok = sc_vecdeque_push(&vdq, i);
+        assert(ok);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 900);
+
+    for (int i = 100; i < 1000; ++i) {
+        int v = sc_vecdeque_pop(&vdq);
+        assert(v == i);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    sc_vecdeque_destroy(&vdq);
+}
+
+static void test_vecdeque_push_hole() {
+    struct SC_VECDEQUE(int) vdq = SC_VECDEQUE_INITIALIZER;
+
+    bool ok = sc_vecdeque_reserve(&vdq, 20);
+    assert(ok);
+    assert(vdq.cap == 20);
+
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    for (int i = 0; i < 20; ++i) {
+        int *p = sc_vecdeque_push_hole(&vdq);
+        assert(p);
+        *p = i * 10;
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 20);
+
+    for (int i = 0; i < 10; ++i) {
+        int v = sc_vecdeque_pop(&vdq);
+        assert(v == i * 10);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 10);
+
+    for (int i = 20; i < 30; ++i) {
+        int *p = sc_vecdeque_push_hole(&vdq);
+        assert(p);
+        *p = i * 10;
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 20);
+
+    for (int i = 10; i < 30; ++i) {
+        int v = sc_vecdeque_pop(&vdq);
+        assert(v == i * 10);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    sc_vecdeque_destroy(&vdq);
+}
+
+int main(int argc, char *argv[]) {
+    (void) argc;
+    (void) argv;
+
+    test_vecdeque_push_pop();
+    test_vecdeque_reserve();
+    test_vecdeque_grow();
+    test_vecdeque_push_hole();
+
+    return 0;
+}

server/src/main/java/com/genymobile/scrcpy/AudioEncoder.java

@@ -183,6 +183,8 @@ public final class AudioEncoder {
         thread = new Thread(() -> {
             try {
                 encode();
+            } catch (ConfigurationException e) {
+                // Do not print stack trace, a user-friendly error-message has already been logged
             } catch (IOException e) {
                 Ln.e("Audio encoding error", e);
             } finally {
@@ -247,7 +249,7 @@ public final class AudioEncoder {
     }
 
     @TargetApi(Build.VERSION_CODES.M)
-    public void encode() throws IOException {
+    public void encode() throws IOException, ConfigurationException {
         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.R) {
             Ln.w("Audio disabled: it is not supported before Android 11");
             streamer.writeDisableStream(false);
@@ -259,7 +261,6 @@ public final class AudioEncoder {
 
         boolean mediaCodecStarted = false;
         boolean recorderStarted = false;
-        boolean configurationError = false;
         try {
             Codec codec = streamer.getCodec();
             mediaCodec = createMediaCodec(codec, encoderName);
@@ -279,7 +280,9 @@ public final class AudioEncoder {
                 if (Build.VERSION.SDK_INT == Build.VERSION_CODES.R) {
                     Ln.e("Failed to start audio capture");
                     Ln.e("On Android 11, it is only possible to capture in foreground, make sure that the device is unlocked when starting scrcpy.");
-                    throw new ConfigurationException("Unsupported audio capture");
+                    // Continue to mirror without audio (configurationError is left to false)
+                    streamer.writeDisableStream(false);
+                    return;
                 }
             } finally {
                 stopWorkaroundAndroid11();
@@ -320,15 +323,14 @@ public final class AudioEncoder {
 
             waitEnded();
         } catch (ConfigurationException e) {
-            // Do not print stack trace, a user-friendly error-message has already been logged
-            // Notify the error to scrcpy to make it exit
-            configurationError = true;
+            // Notify the error to make scrcpy exit
+            streamer.writeDisableStream(true);
+            throw e;
+        } catch (Throwable e) {
+            // Notify the client that the audio could not be captured
+            streamer.writeDisableStream(false);
+            throw e;
         } finally {
-            if (!recorderStarted) {
-                // Notify the client that the audio could not be captured
-                streamer.writeDisableStream(configurationError);
-            }
-
             // Cleanup everything (either at the end or on error at any step of the initialization)
             if (mediaCodecThread != null) {
                 Looper looper = mediaCodecThread.getLooper();