enable async resizing

Most of the fields are initialized dynamically.

app/meson.build

@@ -15,6 +15,7 @@ src = [
     'src/opengl.c',
     'src/receiver.c',
     'src/recorder.c',
+    'src/resizer.c',
     'src/scrcpy.c',
     'src/screen.c',
     'src/server.c',
@@ -46,6 +47,7 @@ if not get_option('crossbuild_windows')
         dependency('libavformat'),
         dependency('libavcodec'),
         dependency('libavutil'),
+        dependency('libswscale'),
         dependency('sdl2'),
     ]
 

app/src/cli.c

@@ -643,6 +643,7 @@ guess_record_format(const char *filename) {
 
 static bool
 parse_scale_filter(const char *optarg, enum sc_scale_filter *filter) {
+    // TODO store in a map and loop over the entries instead
     if (!strcmp(optarg, "none")) {
         *filter = SC_SCALE_FILTER_NONE;
         return true;
@@ -651,8 +652,49 @@ parse_scale_filter(const char *optarg, enum sc_scale_filter *filter) {
         *filter = SC_SCALE_FILTER_TRILINEAR;
         return true;
     }
+    if (!strcmp(optarg, "bilinear")) {
+        *filter = SC_SCALE_FILTER_BILINEAR;
+        return true;
+    }
+    if (!strcmp(optarg, "bicubic")) {
+        *filter = SC_SCALE_FILTER_BICUBIC;
+        return true;
+    }
+    if (!strcmp(optarg, "x")) {
+        *filter = SC_SCALE_FILTER_X;
+        return true;
+    }
+    if (!strcmp(optarg, "point")) {
+        *filter = SC_SCALE_FILTER_POINT;
+        return true;
+    }
+    if (!strcmp(optarg, "area")) {
+        *filter = SC_SCALE_FILTER_AREA;
+        return true;
+    }
+    if (!strcmp(optarg, "bicublin")) {
+        *filter = SC_SCALE_FILTER_BICUBLIN;
+        return true;
+    }
+    if (!strcmp(optarg, "gauss")) {
+        *filter = SC_SCALE_FILTER_GAUSS;
+        return true;
+    }
+    if (!strcmp(optarg, "sinc")) {
+        *filter = SC_SCALE_FILTER_SINC;
+        return true;
+    }
+    if (!strcmp(optarg, "lanczos")) {
+        *filter = SC_SCALE_FILTER_LANCZOS;
+        return true;
+    }
+    if (!strcmp(optarg, "spline")) {
+        *filter = SC_SCALE_FILTER_SPLINE;
+        return true;
+    }
+
     LOGE("Unsupported scale filter: %s "
-         "(expected \"none\" or \"trilinear\")", optarg);
+         "(expected one of [TODO])", optarg);
     return false;
 }
 

app/src/decoder.c

@@ -2,6 +2,7 @@
 
 #include <libavformat/avformat.h>
 #include <libavutil/time.h>
+#include <SDL2/SDL_events.h>
 #include <unistd.h>
 
 #include "events.h"
@@ -13,26 +14,12 @@
 // set the decoded frame as ready for rendering, and notify
 static void
 push_frame(struct decoder *decoder) {
-    bool previous_frame_skipped;
-    video_buffer_offer_decoded_frame(decoder->video_buffer,
-                                     &previous_frame_skipped);
-    if (previous_frame_skipped) {
-        // the previous callback will consume this frame
-        return;
-    }
-
-    decoder->cbs->on_new_frame(decoder, decoder->cbs_userdata);
+    video_buffer_producer_offer_frame(decoder->video_buffer, &decoder->frame);
 }
 
 void
-decoder_init(struct decoder *decoder, struct video_buffer *vb,
-             const struct decoder_callbacks *cbs, void *cbs_userdata) {
+decoder_init(struct decoder *decoder, struct video_buffer *vb) {
     decoder->video_buffer = vb;
-
-    assert(cbs);
-    assert(cbs->on_new_frame);
-    decoder->cbs = cbs;
-    decoder->cbs_userdata = cbs_userdata;
 }
 
 bool
@@ -49,11 +36,19 @@ decoder_open(struct decoder *decoder, const AVCodec *codec) {
         return false;
     }
 
+    decoder->frame = av_frame_alloc();
+    if (!decoder->frame) {
+        avcodec_close(decoder->codec_ctx);
+        avcodec_free_context(&decoder->codec_ctx);
+        return false;
+    }
+
     return true;
 }
 
 void
 decoder_close(struct decoder *decoder) {
+    av_frame_free(&decoder->frame);
     avcodec_close(decoder->codec_ctx);
     avcodec_free_context(&decoder->codec_ctx);
 }
@@ -68,8 +63,7 @@ decoder_push(struct decoder *decoder, const AVPacket *packet) {
         LOGE("Could not send video packet: %d", ret);
         return false;
     }
-    ret = avcodec_receive_frame(decoder->codec_ctx,
-                                decoder->video_buffer->decoding_frame);
+    ret = avcodec_receive_frame(decoder->codec_ctx, decoder->frame);
     if (!ret) {
         // a frame was received
         push_frame(decoder);
@@ -80,7 +74,7 @@ decoder_push(struct decoder *decoder, const AVPacket *packet) {
 #else
     int got_picture;
     int len = avcodec_decode_video2(decoder->codec_ctx,
-                                    decoder->video_buffer->decoding_frame,
+                                    decoder->frame,
                                     &got_picture,
                                     packet);
     if (len < 0) {

app/src/decoder.h

@@ -11,20 +11,11 @@ struct video_buffer;
 struct decoder {
     struct video_buffer *video_buffer;
     AVCodecContext *codec_ctx;
-
-    const struct decoder_callbacks *cbs;
-    void *cbs_userdata;
-};
-
-struct decoder_callbacks {
-     // Called when a new frame can be consumed by
-     // video_buffer_take_rendering_frame(decoder->video_buffer).
-    void (*on_new_frame)(struct decoder *decoder, void *userdata);
+    AVFrame *frame;
 };
 
 void
-decoder_init(struct decoder *decoder, struct video_buffer *vb,
-             const struct decoder_callbacks *cbs, void *cbs_userdata);
+decoder_init(struct decoder *decoder, struct video_buffer *vb);
 
 bool
 decoder_open(struct decoder *decoder, const AVCodec *codec);

app/src/fps_counter.c

@@ -168,7 +168,7 @@ fps_counter_add_rendered_frame(struct fps_counter *counter) {
 }
 
 void
-fps_counter_add_skipped_frame(struct fps_counter *counter) {
+fps_counter_add_skipped_frames(struct fps_counter *counter, unsigned n) {
     if (!is_started(counter)) {
         return;
     }
@@ -176,6 +176,6 @@ fps_counter_add_skipped_frame(struct fps_counter *counter) {
     sc_mutex_lock(&counter->mutex);
     uint32_t now = SDL_GetTicks();
     check_interval_expired(counter, now);
-    ++counter->nr_skipped;
+    counter->nr_skipped += n;
     sc_mutex_unlock(&counter->mutex);
 }

app/src/fps_counter.h

@@ -54,6 +54,6 @@ void
 fps_counter_add_rendered_frame(struct fps_counter *counter);
 
 void
-fps_counter_add_skipped_frame(struct fps_counter *counter);
+fps_counter_add_skipped_frames(struct fps_counter *counter, unsigned n);
 
 #endif

app/src/input_manager.c

@@ -480,9 +480,7 @@ input_manager_process_key(struct input_manager *im,
                 return;
             case SDLK_i:
                 if (!shift && !repeat && down) {
-                    struct fps_counter *fps_counter =
-                        im->video_buffer->fps_counter;
-                    switch_fps_counter_state(fps_counter);
+                    switch_fps_counter_state(im->fps_counter);
                 }
                 return;
             case SDLK_n:

app/src/input_manager.h

@@ -16,6 +16,7 @@
 struct input_manager {
     struct controller *controller;
     struct video_buffer *video_buffer;
+    struct fps_counter *fps_counter;
     struct screen *screen;
 
     // SDL reports repeated events as a boolean, but Android expects the actual

app/src/resizer.c

@@ -0,0 +1,183 @@
+#include "resizer.h"
+
+#include <assert.h>
+#include <libswscale/swscale.h>
+
+#include "util/log.h"
+
+bool
+sc_resizer_init(struct sc_resizer *resizer, struct video_buffer *vb_in,
+                struct video_buffer *vb_out, enum sc_scale_filter scale_filter,
+                struct size size) {
+    bool ok = sc_mutex_init(&resizer->mutex);
+    if (!ok) {
+        return false;
+    }
+
+    ok = sc_cond_init(&resizer->req_cond);
+    if (!ok) {
+        sc_mutex_destroy(&resizer->mutex);
+        return false;
+    }
+
+    resizer->resized_frame = av_frame_alloc();
+    if (!resizer->resized_frame) {
+        sc_cond_destroy(&resizer->req_cond);
+        sc_mutex_destroy(&resizer->mutex);
+        return false;
+    }
+
+    resizer->vb_in = vb_in;
+    resizer->vb_out = vb_out;
+    resizer->scale_filter = scale_filter;
+    resizer->size = size;
+
+    resizer->input_frame = NULL;
+    resizer->has_request = false;
+    resizer->has_new_frame = false;
+    resizer->interrupted = false;
+
+    return true;
+}
+
+void
+sc_resizer_destroy(struct sc_resizer *resizer) {
+    av_frame_free(&resizer->resized_frame);
+    sc_cond_destroy(&resizer->req_cond);
+    sc_mutex_destroy(&resizer->mutex);
+}
+
+static int
+to_sws_filter(enum sc_scale_filter scale_filter) {
+    switch (scale_filter) {
+        case SC_SCALE_FILTER_BILINEAR:  return SWS_BILINEAR;
+        case SC_SCALE_FILTER_BICUBIC:   return SWS_BICUBIC;
+        case SC_SCALE_FILTER_X:         return SWS_X;
+        case SC_SCALE_FILTER_POINT:     return SWS_POINT;
+        case SC_SCALE_FILTER_AREA:      return SWS_AREA;
+        case SC_SCALE_FILTER_BICUBLIN:  return SWS_BICUBLIN;
+        case SC_SCALE_FILTER_GAUSS:     return SWS_GAUSS;
+        case SC_SCALE_FILTER_SINC:      return SWS_SINC;
+        case SC_SCALE_FILTER_LANCZOS:   return SWS_LANCZOS;
+        case SC_SCALE_FILTER_SPLINE:    return SWS_SPLINE;
+        default: assert(!"unsupported filter");
+    }
+}
+
+static bool
+sc_resizer_swscale(struct sc_resizer *resizer) {
+    assert(!resizer->resized_frame->buf[0]); // The frame must be "empty"
+    assert(resizer->size.width);
+    assert(resizer->size.height);
+
+    const AVFrame *in = resizer->input_frame;
+    struct size size = resizer->size;
+
+    AVFrame *out = resizer->resized_frame;
+    out->format = AV_PIX_FMT_RGB24;
+    out->width = size.width;
+    out->height = size.height;
+
+    int ret = av_frame_get_buffer(out, 32);
+    if (ret < 0) {
+        return false;
+    }
+
+    int flags = to_sws_filter(resizer->scale_filter);
+    struct SwsContext *ctx =
+        sws_getContext(in->width, in->height, AV_PIX_FMT_YUV420P,
+                       size.width, size.height, AV_PIX_FMT_RGB24, flags, NULL,
+                       NULL, NULL);
+    if (!ctx) {
+        av_frame_unref(out);
+        return false;
+    }
+
+    sws_scale(ctx, (const uint8_t *const *) in->data, in->linesize, 0,
+              in->height, out->data, out->linesize);
+    sws_freeContext(ctx);
+
+    return true;
+}
+
+static int
+run_resizer(void *data) {
+    struct sc_resizer *resizer = data;
+
+    sc_mutex_lock(&resizer->mutex);
+    while (!resizer->interrupted) {
+        while (!resizer->interrupted && !resizer->has_request) {
+            sc_cond_wait(&resizer->req_cond, &resizer->mutex);
+        }
+
+        if (resizer->has_new_frame) {
+            unsigned skipped;
+            resizer->input_frame =
+                video_buffer_consumer_take_frame(resizer->vb_in, &skipped);
+
+            (void) skipped; // FIXME forward skipped frames count
+            resizer->has_new_frame = false;
+        }
+
+        resizer->has_request = false;
+        sc_mutex_unlock(&resizer->mutex);
+
+        // Do the actual work without mutex
+        sc_resizer_swscale(resizer);
+
+        video_buffer_producer_offer_frame(resizer->vb_out,
+                                          &resizer->resized_frame);
+
+        sc_mutex_lock(&resizer->mutex);
+    }
+    sc_mutex_unlock(&resizer->mutex);
+
+    return 0;
+}
+
+bool
+sc_resizer_start(struct sc_resizer *resizer) {
+    LOGD("Starting resizer thread");
+
+    bool ok = sc_thread_create(&resizer->thread, run_resizer, "resizer",
+                               resizer);
+    if (!ok) {
+        LOGE("Could not start resizer thread");
+        return false;
+    }
+
+    return true;
+}
+
+void
+sc_resizer_stop(struct sc_resizer *resizer) {
+    sc_mutex_lock(&resizer->mutex);
+    resizer->interrupted = true;
+    sc_cond_signal(&resizer->req_cond);
+    sc_mutex_unlock(&resizer->mutex);
+
+    video_buffer_interrupt(resizer->vb_out);
+}
+
+void
+sc_resizer_join(struct sc_resizer *resizer) {
+    sc_thread_join(&resizer->thread, NULL);
+}
+
+void
+sc_resizer_process_new_frame(struct sc_resizer *resizer) {
+    sc_mutex_lock(&resizer->mutex);
+    resizer->has_request = true;
+    resizer->has_new_frame = true;
+    sc_cond_signal(&resizer->req_cond);
+    sc_mutex_unlock(&resizer->mutex);
+}
+
+void
+sc_resizer_process_new_size(struct sc_resizer *resizer, struct size size) {
+    sc_mutex_lock(&resizer->mutex);
+    resizer->size = size;
+    resizer->has_request = true;
+    sc_cond_signal(&resizer->req_cond);
+    sc_mutex_unlock(&resizer->mutex);
+}

app/src/resizer.h

@@ -0,0 +1,56 @@
+#ifndef SC_RESIZER
+#define SC_RESIZER
+
+#include "common.h"
+
+#include <stdbool.h>
+#include <libavformat/avformat.h>
+
+#include "coords.h"
+#include "scrcpy.h"
+#include "util/thread.h"
+#include "video_buffer.h"
+
+struct sc_resizer {
+    struct video_buffer *vb_in;
+    struct video_buffer *vb_out;
+    enum sc_scale_filter scale_filter;
+    struct size size;
+
+    // valid until the next call to video_buffer_consumer_take_frame(vb_in)
+    const AVFrame *input_frame;
+    AVFrame *resized_frame;
+
+    sc_thread thread;
+    sc_mutex mutex;
+    sc_cond req_cond;
+
+    bool has_request;
+    bool has_new_frame;
+    bool interrupted;
+};
+
+bool
+sc_resizer_init(struct sc_resizer *resizer, struct video_buffer *vb_in,
+                struct video_buffer *vb_out, enum sc_scale_filter scale_filter,
+                struct size size);
+
+void
+sc_resizer_destroy(struct sc_resizer *resizer);
+
+bool
+sc_resizer_start(struct sc_resizer *resizer);
+
+void
+sc_resizer_stop(struct sc_resizer *resizer);
+
+void
+sc_resizer_join(struct sc_resizer *resizer);
+
+void
+sc_resizer_process_new_frame(struct sc_resizer *resizer);
+
+void
+sc_resizer_process_new_size(struct sc_resizer *resizer, struct size size);
+
+#endif

app/src/scrcpy.c

@@ -42,6 +42,7 @@ static struct file_handler file_handler;
 static struct input_manager input_manager = {
     .controller = &controller,
     .video_buffer = &video_buffer,
+    .fps_counter = &fps_counter,
     .screen = &screen,
     .repeat = 0,
 
@@ -267,11 +268,11 @@ av_log_callback(void *avcl, int level, const char *fmt, va_list vl) {
 }
 
 static void
-decoder_on_new_frame(struct decoder *decoder, void *userdata) {
-    (void) decoder;
+video_buffer_on_frame_available(struct video_buffer *vb, void *userdata) {
+    (void) vb;
     (void) userdata;
 
-    screen_on_new_frame(&screen);
+    screen_on_frame_available(&screen);
 }
 
 bool
@@ -340,8 +341,12 @@ scrcpy(const struct scrcpy_options *options) {
         }
         fps_counter_initialized = true;
 
-        if (!video_buffer_init(&video_buffer, &fps_counter,
-                               options->render_expired_frames)) {
+        static const struct video_buffer_callbacks video_buffer_cbs = {
+            .on_frame_available = video_buffer_on_frame_available,
+        };
+
+        if (!video_buffer_init(&video_buffer, options->render_expired_frames,
+                               &video_buffer_cbs, NULL)) {
             goto end;
         }
         video_buffer_initialized = true;
@@ -354,11 +359,7 @@ scrcpy(const struct scrcpy_options *options) {
             file_handler_initialized = true;
         }
 
-        static const struct decoder_callbacks decoder_cbs = {
-            .on_new_frame = decoder_on_new_frame,
-        };
-
-        decoder_init(&decoder, &video_buffer, &decoder_cbs, NULL);
+        decoder_init(&decoder, &video_buffer);
         dec = &decoder;
     }
 
@@ -378,13 +379,6 @@ scrcpy(const struct scrcpy_options *options) {
 
     stream_init(&stream, server.video_socket, dec, rec);
 
-    // now we consumed the header values, the socket receives the video stream
-    // start the stream
-    if (!stream_start(&stream)) {
-        goto end;
-    }
-    stream_started = true;
-
     if (options->display) {
         if (options->control) {
             if (!controller_init(&controller, server.control_socket)) {
@@ -401,7 +395,7 @@ scrcpy(const struct scrcpy_options *options) {
         const char *window_title =
             options->window_title ? options->window_title : device_name;
 
-        screen_init(&screen, &video_buffer);
+        screen_init(&screen, &video_buffer, &fps_counter);
 
         if (!screen_init_rendering(&screen, window_title, frame_size,
                                    options->always_on_top, options->window_x,
@@ -427,6 +421,13 @@ scrcpy(const struct scrcpy_options *options) {
         }
     }
 
+    // now we consumed the header values, the socket receives the video stream
+    // start the stream
+    if (!stream_start(&stream)) {
+        goto end;
+    }
+    stream_started = true;
+
     input_manager_init(&input_manager, options);
 
     ret = event_loop(options);

app/src/scrcpy.h

@@ -44,6 +44,17 @@ struct sc_port_range {
 enum sc_scale_filter {
     SC_SCALE_FILTER_NONE,
     SC_SCALE_FILTER_TRILINEAR, // mipmaps
+    SC_SCALE_FILTER_BILINEAR,
+    SC_SCALE_FILTER_BICUBIC,
+    SC_SCALE_FILTER_X,
+    SC_SCALE_FILTER_POINT,
+    SC_SCALE_FILTER_AREA,
+    SC_SCALE_FILTER_BICUBLIN,
+    SC_SCALE_FILTER_GAUSS,
+    SC_SCALE_FILTER_SINC,
+    SC_SCALE_FILTER_LANCZOS,
+    SC_SCALE_FILTER_SPLINE,
+    SC_SCALE_FILTER__COUNT,
 };
 
 #define SC_WINDOW_POSITION_UNDEFINED (-0x8000)

app/src/screen.c

@@ -191,23 +191,32 @@ screen_update_content_rect(struct screen *screen) {
 }
 
 void
-screen_init(struct screen *screen, struct video_buffer *vb) {
-    *screen = (struct screen) SCREEN_INITIALIZER;
+screen_init(struct screen *screen, struct video_buffer *vb,
+            struct fps_counter *fps_counter) {
     screen->vb = vb;
+    screen->fps_counter = fps_counter;
+
+    screen->resize_pending = false;
+    screen->has_frame = false;
+    screen->fullscreen = false;
+    screen->maximized = false;
 }
 
 static inline SDL_Texture *
 create_texture(struct screen *screen) {
     SDL_Renderer *renderer = screen->renderer;
     struct size size = screen->frame_size;
-    SDL_Texture *texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_YV12,
+    SDL_PixelFormatEnum fmt = screen->use_swscale ? SDL_PIXELFORMAT_RGB24
+                                                  : SDL_PIXELFORMAT_YV12;
+    SDL_Texture *texture = SDL_CreateTexture(renderer, fmt,
                                              SDL_TEXTUREACCESS_STREAMING,
                                              size.width, size.height);
     if (!texture) {
         return NULL;
     }
 
-    if (screen->mipmaps) {
+    if (screen->scale_filter == SC_SCALE_FILTER_TRILINEAR) {
+        assert(!screen->use_swscale);
         struct sc_opengl *gl = &screen->gl;
 
         SDL_GL_BindTexture(texture, NULL, NULL);
@@ -223,6 +232,25 @@ create_texture(struct screen *screen) {
     return texture;
 }
 
+static inline bool
+is_swscale(enum sc_scale_filter scale_filter) {
+    return scale_filter != SC_SCALE_FILTER_NONE
+        && scale_filter != SC_SCALE_FILTER_TRILINEAR;
+}
+
+static void
+on_resizer_frame_available(struct video_buffer *vb, void *userdata) {
+    (void) vb;
+    (void) userdata;
+
+    static SDL_Event new_frame_event = {
+        .type = EVENT_NEW_FRAME,
+    };
+
+    // Post the event on the UI thread
+    SDL_PushEvent(&new_frame_event);
+}
+
 bool
 screen_init_rendering(struct screen *screen, const char *window_title,
                       struct size frame_size, bool always_on_top,
@@ -295,10 +323,10 @@ screen_init_rendering(struct screen *screen, const char *window_title,
                                                2, 0  /* OpenGL ES 2.0+ */);
             if (supports_mipmaps) {
                 LOGI("Trilinear filtering enabled");
-                screen->mipmaps = true;
             } else {
                 LOGW("Trilinear filtering disabled "
                      "(OpenGL 3.0+ or ES 2.0+ required)");
+                scale_filter = SC_SCALE_FILTER_NONE;
             }
         } else {
             LOGI("Trilinear filtering disabled");
@@ -307,6 +335,42 @@ screen_init_rendering(struct screen *screen, const char *window_title,
         LOGD("Trilinear filtering disabled (not an OpenGL renderer)");
     }
 
+    screen->use_swscale = is_swscale(scale_filter);
+    if (screen->use_swscale) {
+        static const struct video_buffer_callbacks video_buffer_cbs = {
+            .on_frame_available = on_resizer_frame_available,
+        };
+        bool ok = video_buffer_init(&screen->resizer_vb, false,
+                                    &video_buffer_cbs, NULL);
+        if (!ok) {
+            LOGE("Could not create resizer video buffer");
+            SDL_DestroyRenderer(screen->renderer);
+            SDL_DestroyWindow(screen->window);
+            return false;
+        }
+
+        ok = sc_resizer_init(&screen->resizer, screen->vb, &screen->resizer_vb,
+                             scale_filter, window_size);
+        if (!ok) {
+            LOGE("Could not create resizer");
+            video_buffer_destroy(&screen->resizer_vb);
+            SDL_DestroyRenderer(screen->renderer);
+            SDL_DestroyWindow(screen->window);
+            return false;
+        }
+
+        ok = sc_resizer_start(&screen->resizer);
+        if (!ok) {
+            LOGE("Could not start resizer");
+            sc_resizer_destroy(&screen->resizer);
+            video_buffer_destroy(&screen->resizer_vb);
+            SDL_DestroyRenderer(screen->renderer);
+            SDL_DestroyWindow(screen->window);
+        }
+    }
+
+    screen->scale_filter = scale_filter;
+
     SDL_Surface *icon = read_xpm(icon_xpm);
     if (icon) {
         SDL_SetWindowIcon(screen->window, icon);
@@ -322,7 +386,6 @@ screen_init_rendering(struct screen *screen, const char *window_title,
         LOGC("Could not create texture: %s", SDL_GetError());
         SDL_DestroyRenderer(screen->renderer);
         SDL_DestroyWindow(screen->window);
-        screen_destroy(screen);
         return false;
     }
 
@@ -343,6 +406,11 @@ screen_show_window(struct screen *screen) {
 
 void
 screen_destroy(struct screen *screen) {
+    if (screen->use_swscale) {
+        sc_resizer_stop(&screen->resizer);
+        sc_resizer_join(&screen->resizer);
+        sc_resizer_destroy(&screen->resizer);
+    }
     if (screen->texture) {
         SDL_DestroyTexture(screen->texture);
     }
@@ -438,21 +506,33 @@ prepare_for_frame(struct screen *screen, struct size new_frame_size) {
 // write the frame into the texture
 static void
 update_texture(struct screen *screen, const AVFrame *frame) {
-    SDL_UpdateYUVTexture(screen->texture, NULL,
-            frame->data[0], frame->linesize[0],
-            frame->data[1], frame->linesize[1],
-            frame->data[2], frame->linesize[2]);
+    if (screen->use_swscale) {
+        SDL_UpdateTexture(screen->texture, NULL, frame->data[0],
+                          frame->linesize[0]);
+    } else {
+        SDL_UpdateYUVTexture(screen->texture, NULL,
+                frame->data[0], frame->linesize[0],
+                frame->data[1], frame->linesize[1],
+                frame->data[2], frame->linesize[2]);
 
-    if (screen->mipmaps) {
-        SDL_GL_BindTexture(screen->texture, NULL, NULL);
-        screen->gl.GenerateMipmap(GL_TEXTURE_2D);
-        SDL_GL_UnbindTexture(screen->texture);
+        if (screen->scale_filter == SC_SCALE_FILTER_TRILINEAR) {
+            SDL_GL_BindTexture(screen->texture, NULL, NULL);
+            screen->gl.GenerateMipmap(GL_TEXTURE_2D);
+            SDL_GL_UnbindTexture(screen->texture);
+        }
     }
 }
 
 static bool
 screen_update_frame(struct screen *screen) {
-    const AVFrame *frame = video_buffer_take_rendering_frame(screen->vb);
+    unsigned skipped;
+    struct video_buffer *vb = screen->use_swscale ? &screen->resizer_vb
+                                                  : screen->vb;
+    const AVFrame *frame = video_buffer_consumer_take_frame(vb, &skipped);
+
+    fps_counter_add_skipped_frames(screen->fps_counter, skipped);
+    fps_counter_add_rendered_frame(screen->fps_counter);
+
     struct size new_frame_size = {frame->width, frame->height};
     if (!prepare_for_frame(screen, new_frame_size)) {
         return false;
@@ -649,13 +729,15 @@ screen_hidpi_scale_coords(struct screen *screen, int32_t *x, int32_t *y) {
 }
 
 void
-screen_on_new_frame(struct screen *screen) {
-    (void) screen;
+screen_on_frame_available(struct screen *screen) {
+    if (screen->use_swscale) {
+        sc_resizer_process_new_frame(&screen->resizer);
+    } else {
+        static SDL_Event new_frame_event = {
+            .type = EVENT_NEW_FRAME,
+        };
 
-    static SDL_Event new_frame_event = {
-        .type = EVENT_NEW_FRAME,
-    };
-
-    // Post the event on the UI thread
-    SDL_PushEvent(&new_frame_event);
+        // Post the event on the UI thread
+        SDL_PushEvent(&new_frame_event);
+    }
 }

app/src/screen.h

@@ -9,12 +9,16 @@
 
 #include "coords.h"
 #include "opengl.h"
+#include "resizer.h"
 #include "scrcpy.h"
+#include "video_buffer.h"
 
 struct video_buffer;
 
 struct screen {
     struct video_buffer *vb;
+    struct fps_counter *fps_counter;
+
     SDL_Window *window;
     SDL_Renderer *renderer;
     SDL_Texture *texture;
@@ -34,46 +38,20 @@ struct screen {
     bool has_frame;
     bool fullscreen;
     bool maximized;
-    bool no_window;
     bool mipmaps;
-};
 
-#define SCREEN_INITIALIZER { \
-    .vb = NULL, \
-    .window = NULL, \
-    .renderer = NULL, \
-    .texture = NULL, \
-    .gl = {0}, \
-    .frame_size = { \
-        .width = 0, \
-        .height = 0, \
-    }, \
-    .content_size = { \
-        .width = 0, \
-        .height = 0, \
-    }, \
-    .resize_pending = false, \
-    .windowed_content_size = { \
-        .width = 0, \
-        .height = 0, \
-    }, \
-    .rotation = 0, \
-    .rect = { \
-        .x = 0, \
-        .y = 0, \
-        .w = 0, \
-        .h = 0, \
-    }, \
-    .has_frame = false, \
-    .fullscreen = false, \
-    .maximized = false, \
-    .no_window = false, \
-    .mipmaps = false, \
-}
+    enum sc_scale_filter scale_filter;
+    bool use_swscale;
+
+    // For swscale resizing
+    struct video_buffer resizer_vb;
+    struct sc_resizer resizer;
+};
 
 // initialize default values
 void
-screen_init(struct screen *screen, struct video_buffer *vb);
+screen_init(struct screen *screen, struct video_buffer *vb,
+            struct fps_counter *fps_counter);
 
 // initialize screen, create window, renderer and texture (window is hidden)
 // window_x and window_y accept SC_WINDOW_POSITION_UNDEFINED
@@ -141,6 +119,6 @@ screen_hidpi_scale_coords(struct screen *screen, int32_t *x, int32_t *y);
 // Notify the screen that a new frame is available in the video_buffer.
 // Called from a separate thread.
 void
-screen_on_new_frame(struct screen *screen);
+screen_on_frame_available(struct screen *screen);
 
 #endif

app/src/video_buffer.c

@@ -7,129 +7,130 @@
 #include "util/log.h"
 
 bool
-video_buffer_init(struct video_buffer *vb, struct fps_counter *fps_counter,
-                  bool render_expired_frames) {
-    vb->fps_counter = fps_counter;
-
-    vb->decoding_frame = av_frame_alloc();
-    if (!vb->decoding_frame) {
+video_buffer_init(struct video_buffer *vb, bool wait_consumer,
+                  const struct video_buffer_callbacks *cbs,
+                  void *cbs_userdata) {
+    vb->pending_frame = av_frame_alloc();
+    if (!vb->pending_frame) {
         goto error_0;
     }
 
-    vb->pending_frame = av_frame_alloc();
-    if (!vb->pending_frame) {
+    vb->consumer_frame = av_frame_alloc();
+    if (!vb->consumer_frame) {
         goto error_1;
     }
 
-    vb->rendering_frame = av_frame_alloc();
-    if (!vb->rendering_frame) {
-        goto error_2;
-    }
-
     bool ok = sc_mutex_init(&vb->mutex);
     if (!ok) {
-        goto error_3;
+        goto error_2;
     }
 
-    vb->render_expired_frames = render_expired_frames;
-    if (render_expired_frames) {
+    vb->wait_consumer = wait_consumer;
+    if (wait_consumer) {
         ok = sc_cond_init(&vb->pending_frame_consumed_cond);
         if (!ok) {
             sc_mutex_destroy(&vb->mutex);
             goto error_2;
         }
-        // interrupted is not used if expired frames are not rendered
-        // since offering a frame will never block
+        // interrupted is not used if wait_consumer is disabled since offering
+        // a frame will never block
         vb->interrupted = false;
     }
 
-    // there is initially no rendering frame, so consider it has already been
-    // consumed
+    // there is initially no frame, so consider it has already been consumed
     vb->pending_frame_consumed = true;
 
+    vb->skipped = 0;
+
+    assert(cbs);
+    assert(cbs->on_frame_available);
+    vb->cbs = cbs;
+    vb->cbs_userdata = cbs_userdata;
+
     return true;
 
-error_3:
-    av_frame_free(&vb->rendering_frame);
 error_2:
-    av_frame_free(&vb->pending_frame);
+    av_frame_free(&vb->consumer_frame);
 error_1:
-    av_frame_free(&vb->decoding_frame);
+    av_frame_free(&vb->pending_frame);
 error_0:
     return false;
 }
 
 void
 video_buffer_destroy(struct video_buffer *vb) {
-    if (vb->render_expired_frames) {
+    if (vb->wait_consumer) {
         sc_cond_destroy(&vb->pending_frame_consumed_cond);
     }
     sc_mutex_destroy(&vb->mutex);
-    av_frame_free(&vb->rendering_frame);
+    av_frame_free(&vb->consumer_frame);
     av_frame_free(&vb->pending_frame);
-    av_frame_free(&vb->decoding_frame);
 }
 
-static void
-video_buffer_swap_decoding_frame(struct video_buffer *vb) {
-    sc_mutex_assert(&vb->mutex);
-    AVFrame *tmp = vb->decoding_frame;
-    vb->decoding_frame = vb->pending_frame;
-    vb->pending_frame = tmp;
-}
-
-static void
-video_buffer_swap_rendering_frame(struct video_buffer *vb) {
-    sc_mutex_assert(&vb->mutex);
-    AVFrame *tmp = vb->rendering_frame;
-    vb->rendering_frame = vb->pending_frame;
-    vb->pending_frame = tmp;
+static inline void
+swap_frames(AVFrame **lhs, AVFrame **rhs) {
+    AVFrame *tmp = *lhs;
+    *lhs = *rhs;
+    *rhs = tmp;
 }
 
 void
-video_buffer_offer_decoded_frame(struct video_buffer *vb,
-                                 bool *previous_frame_skipped) {
+video_buffer_producer_offer_frame(struct video_buffer *vb, AVFrame **pframe) {
     sc_mutex_lock(&vb->mutex);
-    if (vb->render_expired_frames) {
+    if (vb->wait_consumer) {
         // wait for the current (expired) frame to be consumed
         while (!vb->pending_frame_consumed && !vb->interrupted) {
             sc_cond_wait(&vb->pending_frame_consumed_cond, &vb->mutex);
         }
-    } else if (!vb->pending_frame_consumed) {
-        fps_counter_add_skipped_frame(vb->fps_counter);
     }
 
-    video_buffer_swap_decoding_frame(vb);
+    av_frame_unref(vb->pending_frame);
+    swap_frames(pframe, &vb->pending_frame);
+
+    bool skipped = !vb->pending_frame_consumed;
+    if (skipped) {
+        ++vb->skipped;
+    }
 
-    *previous_frame_skipped = !vb->pending_frame_consumed;
     vb->pending_frame_consumed = false;
 
     sc_mutex_unlock(&vb->mutex);
+
+    if (!skipped) {
+        // If skipped, then the previous call will consume this frame, the
+        // callback must not be called
+        vb->cbs->on_frame_available(vb, vb->cbs_userdata);
+    }
 }
 
 const AVFrame *
-video_buffer_take_rendering_frame(struct video_buffer *vb) {
+video_buffer_consumer_take_frame(struct video_buffer *vb, unsigned *skipped) {
     sc_mutex_lock(&vb->mutex);
     assert(!vb->pending_frame_consumed);
     vb->pending_frame_consumed = true;
 
-    fps_counter_add_rendered_frame(vb->fps_counter);
+    swap_frames(&vb->consumer_frame, &vb->pending_frame);
+    av_frame_unref(vb->pending_frame);
 
-    video_buffer_swap_rendering_frame(vb);
-
-    if (vb->render_expired_frames) {
+    if (vb->wait_consumer) {
         // unblock video_buffer_offer_decoded_frame()
         sc_cond_signal(&vb->pending_frame_consumed_cond);
     }
+
+    if (skipped) {
+        *skipped = vb->skipped;
+    }
+    vb->skipped = 0; // reset
+
     sc_mutex_unlock(&vb->mutex);
 
-    // rendering_frame is only written from this thread, no need to lock
-    return vb->rendering_frame;
+    // consumer_frame is only written from this thread, no need to lock
+    return vb->consumer_frame;
 }
 
 void
 video_buffer_interrupt(struct video_buffer *vb) {
-    if (vb->render_expired_frames) {
+    if (vb->wait_consumer) {
         sc_mutex_lock(&vb->mutex);
         vb->interrupted = true;
         sc_mutex_unlock(&vb->mutex);

app/src/video_buffer.h

@@ -13,53 +13,62 @@ typedef struct AVFrame AVFrame;
 
 /**
  * There are 3 frames in memory:
- *  - one frame is held by the decoder (decoding_frame)
- *  - one frame is held by the renderer (rendering_frame)
- *  - one frame is shared between the decoder and the renderer (pending_frame)
+ *  - one frame is held by the producer (producer_frame)
+ *  - one frame is held by the consumer (consumer_frame)
+ *  - one frame is shared between the producer and the consumer (pending_frame)
  *
- * The decoder decodes a packet into the decoding_frame (it may takes time).
+ * The producer generates a frame into the producer_frame (it may takes time).
  *
- * Once the frame is decoded, it calls video_buffer_offer_decoded_frame(),
- * which swaps the decoding and pending frames.
+ * Once the frame is produced, it calls video_buffer_producer_offer_frame(),
+ * which swaps the producer and pending frames.
  *
- * When the renderer is notified that a new frame is available, it calls
- * video_buffer_take_rendering_frame() to retrieve it, which swaps the pending
- * and rendering frames. The frame is valid until the next call, without
- * blocking the decoder.
+ * When the consumer is notified that a new frame is available, it calls
+ * video_buffer_consumer_take_frame() to retrieve it, which swaps the pending
+ * and consumer frames. The frame is valid until the next call, without
+ * blocking the producer.
  */
 
 struct video_buffer {
-    AVFrame *decoding_frame;
     AVFrame *pending_frame;
-    AVFrame *rendering_frame;
+    AVFrame *consumer_frame;
 
     sc_mutex mutex;
-    bool render_expired_frames;
+    bool wait_consumer; // never overwrite a pending frame if it is not consumed
     bool interrupted;
 
     sc_cond pending_frame_consumed_cond;
     bool pending_frame_consumed;
 
-    struct fps_counter *fps_counter;
+    unsigned skipped;
+
+    const struct video_buffer_callbacks *cbs;
+    void *cbs_userdata;
+};
+
+struct video_buffer_callbacks {
+    // Called when a new frame can be consumed by
+    // video_buffer_consumer_take_frame(vb)
+    void (*on_frame_available)(struct video_buffer *vb, void *userdata);
 };
 
 bool
-video_buffer_init(struct video_buffer *vb, struct fps_counter *fps_counter,
-                  bool render_expired_frames);
+video_buffer_init(struct video_buffer *vb, bool wait_consumer,
+                  const struct video_buffer_callbacks *cbs, void *cbs_userdata);
 
 void
 video_buffer_destroy(struct video_buffer *vb);
 
-// set the decoded frame as ready for rendering
-// the output flag is set to report whether the previous frame has been skipped
+// set the producer frame as ready for consuming
+// the produced frame is exchanged with an unused allocated frame
 void
-video_buffer_offer_decoded_frame(struct video_buffer *vb,
-                                 bool *previous_frame_skipped);
+video_buffer_producer_offer_frame(struct video_buffer *vb, AVFrame **pframe);
 
-// mark the rendering frame as consumed and return it
+// mark the consumer frame as consumed and return it
 // the frame is valid until the next call to this function
+// the output parameter "skipped" indicates how many produced frames have been
+// skipped
 const AVFrame *
-video_buffer_take_rendering_frame(struct video_buffer *vb);
+video_buffer_consumer_take_frame(struct video_buffer *vb, unsigned *skipped);
 
 // wake up and avoid any blocking call
 void