Add --list-encoders

Add an option to list the device encoders properly.

PR #3757 <https://github.com/Genymobile/scrcpy/pull/3757>

app/src/cli.c

@@ -68,6 +68,7 @@ enum {
     OPT_AUDIO_CODEC,
     OPT_AUDIO_CODEC_OPTIONS,
     OPT_AUDIO_ENCODER,
+    OPT_LIST_ENCODERS,
 };
 
 struct sc_option {
@@ -141,7 +142,8 @@ static const struct sc_option options[] = {
         .longopt = "audio-encoder",
         .argdesc = "name",
         .text = "Use a specific MediaCodec audio encoder (depending on the "
-                "codec provided by --audio-codec).",
+                "codec provided by --audio-codec).\n"
+                "The available encoders can be listed by --list-encoders.",
     },
     {
         .shortopt = 'b',
@@ -270,6 +272,11 @@ static const struct sc_option options[] = {
                 "This is a workaround for some devices not behaving as "
                 "expected when setting the device clipboard programmatically.",
     },
+    {
+        .longopt_id = OPT_LIST_ENCODERS,
+        .longopt = "list-encoders",
+        .text = "List video and audio encoders available on the device.",
+    },
     {
         .longopt_id = OPT_LOCK_VIDEO_ORIENTATION,
         .longopt = "lock-video-orientation",
@@ -586,7 +593,8 @@ static const struct sc_option options[] = {
         .longopt = "video-encoder",
         .argdesc = "name",
         .text = "Use a specific MediaCodec video encoder (depending on the "
-                "codec provided by --video-codec).",
+                "codec provided by --video-codec).\n"
+                "The available encoders can be listed by --list-encoders.",
     },
     {
         .shortopt = 'w',
@@ -1792,6 +1800,9 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
                 LOGE("V4L2 (--v4l2-buffer) is only available on Linux.");
                 return false;
 #endif
+            case OPT_LIST_ENCODERS:
+                opts->list_encoders = true;
+                break;
             default:
                 // getopt prints the error message on stderr
                 return false;

app/src/options.c

@@ -72,4 +72,5 @@ const struct scrcpy_options scrcpy_options_default = {
     .start_fps_counter = false,
     .power_on = true,
     .audio = true,
+    .list_encoders = false,
 };

app/src/options.h

@@ -154,6 +154,7 @@ struct scrcpy_options {
     bool start_fps_counter;
     bool power_on;
     bool audio;
+    bool list_encoders;
 };
 
 extern const struct scrcpy_options scrcpy_options_default;

app/src/scrcpy.c

@@ -183,12 +183,16 @@ await_for_server(bool *connected) {
     while (SDL_WaitEvent(&event)) {
         switch (event.type) {
             case SDL_QUIT:
-                *connected = false;
+                if (connected) {
+                    *connected = false;
+                }
                 return true;
             case SC_EVENT_SERVER_CONNECTION_FAILED:
                 return false;
             case SC_EVENT_SERVER_CONNECTED:
-                *connected = true;
+                if (connected) {
+                    *connected = true;
+                }
                 return true;
             default:
                 break;
@@ -339,6 +343,7 @@ scrcpy(struct scrcpy_options *options) {
         .tcpip_dst = options->tcpip_dst,
         .cleanup = options->cleanup,
         .power_on = options->power_on,
+        .list_encoders = options->list_encoders,
     };
 
     static const struct sc_server_callbacks cbs = {
@@ -356,6 +361,12 @@ scrcpy(struct scrcpy_options *options) {
 
     server_started = true;
 
+    if (options->list_encoders) {
+        bool ok = await_for_server(NULL);
+        ret = ok ? SCRCPY_EXIT_SUCCESS : SCRCPY_EXIT_FAILURE;
+        goto end;
+    }
+
     if (options->display) {
         sdl_set_hints(options->render_driver);
     }

app/src/server.c

@@ -300,6 +300,9 @@ execute_server(struct sc_server *server,
         // By default, power_on is true
         ADD_PARAM("power_on=false");
     }
+    if (params->list_encoders) {
+        ADD_PARAM("list_encoders=true");
+    }
 
 #undef ADD_PARAM
 
@@ -848,6 +851,25 @@ run_server(void *data) {
     assert(serial);
     LOGD("Device serial: %s", serial);
 
+    ok = push_server(&server->intr, serial);
+    if (!ok) {
+        goto error_connection_failed;
+    }
+
+    // If --list-encoders is passed, then the server just prints the encoders
+    // then exits.
+    if (params->list_encoders) {
+        sc_pid pid = execute_server(server, params);
+        if (pid == SC_PROCESS_NONE) {
+            goto error_connection_failed;
+        }
+        sc_process_wait(pid, NULL); // ignore exit code
+        sc_process_close(pid);
+        // Wake up await_for_server()
+        server->cbs->on_connected(server, server->cbs_userdata);
+        return 0;
+    }
+
     int r = asprintf(&server->device_socket_name, SC_SOCKET_NAME_PREFIX "%08x",
                      params->scid);
     if (r == -1) {
@@ -857,11 +879,6 @@ run_server(void *data) {
     assert(r == sizeof(SC_SOCKET_NAME_PREFIX) - 1 + 8);
     assert(server->device_socket_name);
 
-    ok = push_server(&server->intr, serial);
-    if (!ok) {
-        goto error_connection_failed;
-    }
-
     ok = sc_adb_tunnel_open(&server->tunnel, &server->intr, serial,
                             server->device_socket_name, params->port_range,
                             params->force_adb_forward);

app/src/server.h

@@ -55,6 +55,7 @@ struct sc_server_params {
     bool select_tcpip;
     bool cleanup;
     bool power_on;
+    bool list_encoders;
 };
 
 struct sc_server {