Add intermediate frame in video buffer

There were only two frames simultaneously:
 - one used by the decoder;
 - one used by the renderer.

When the decoder finished decoding a frame, it swapped it with the
rendering frame.

Adding a third frame provides several benefits:
 - the decoder do not have to wait for the renderer to release the
   mutex;
 - it simplifies the video_buffer API;
 - it makes the rendering frame valid until the next call to
   video_buffer_take_rendering_frame(), which will be useful for
   swscaling on window resize.

app/meson.build

@@ -99,6 +99,9 @@ foreach f : check_functions
   endif
 endforeach
 
+# expose the build type
+conf.set('NDEBUG', get_option('buildtype') != 'debug')
+
 # the version, updated on release
 conf.set_quoted('SCRCPY_VERSION', meson.project_version())
 

app/src/compat.h

@@ -56,7 +56,7 @@
 # define SCRCPY_SDL_HAS_HINT_VIDEO_X11_NET_WM_BYPASS_COMPOSITOR
 #endif
 
-#ifndef HAVE_STRDUP
+#ifdef HAVE_STRDUP
 char *strdup(const char *s);
 #endif
 

app/src/decoder.c

@@ -14,7 +14,17 @@
 // set the decoded frame as ready for rendering, and notify
 static void
 push_frame(struct decoder *decoder) {
-    video_buffer_producer_offer_frame(decoder->video_buffer);
+    bool previous_frame_skipped;
+    video_buffer_offer_decoded_frame(decoder->video_buffer,
+                                     &previous_frame_skipped);
+    if (previous_frame_skipped) {
+        // the previous EVENT_NEW_FRAME will consume this frame
+        return;
+    }
+    static SDL_Event new_frame_event = {
+        .type = EVENT_NEW_FRAME,
+    };
+    SDL_PushEvent(&new_frame_event);
 }
 
 void
@@ -56,7 +66,7 @@ decoder_push(struct decoder *decoder, const AVPacket *packet) {
         return false;
     }
     ret = avcodec_receive_frame(decoder->codec_ctx,
-                                decoder->video_buffer->producer_frame);
+                                decoder->video_buffer->decoding_frame);
     if (!ret) {
         // a frame was received
         push_frame(decoder);

app/src/events.h

@@ -1,2 +1,3 @@
-#define EVENT_NEW_FRAME       SDL_USEREVENT
-#define EVENT_STREAM_STOPPED (SDL_USEREVENT + 1)
+#define EVENT_NEW_SESSION SDL_USEREVENT
+#define EVENT_NEW_FRAME (SDL_USEREVENT + 1)
+#define EVENT_STREAM_STOPPED (SDL_USEREVENT + 2)

app/src/fps_counter.c

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

app/src/input_manager.c

@@ -286,7 +286,7 @@ rotate_client_right(struct screen *screen) {
     screen_set_rotation(screen, new_rotation);
 }
 
-static void
+void
 input_manager_process_text_input(struct input_manager *im,
                                  const SDL_TextInputEvent *event) {
     if (is_shortcut_mod(im, SDL_GetModState())) {
@@ -366,7 +366,7 @@ convert_input_key(const SDL_KeyboardEvent *from, struct control_msg *to,
     return true;
 }
 
-static void
+void
 input_manager_process_key(struct input_manager *im,
                           const SDL_KeyboardEvent *event) {
     // control: indicates the state of the command-line option --no-control
@@ -480,7 +480,9 @@ input_manager_process_key(struct input_manager *im,
                 return;
             case SDLK_i:
                 if (!shift && !repeat && down) {
-                    switch_fps_counter_state(im->fps_counter);
+                    struct fps_counter *fps_counter =
+                        im->video_buffer->fps_counter;
+                    switch_fps_counter_state(fps_counter);
                 }
                 return;
             case SDLK_n:
@@ -549,7 +551,7 @@ convert_mouse_motion(const SDL_MouseMotionEvent *from, struct screen *screen,
     return true;
 }
 
-static void
+void
 input_manager_process_mouse_motion(struct input_manager *im,
                                    const SDL_MouseMotionEvent *event) {
     if (!event->state) {
@@ -603,7 +605,7 @@ convert_touch(const SDL_TouchFingerEvent *from, struct screen *screen,
     return true;
 }
 
-static void
+void
 input_manager_process_touch(struct input_manager *im,
                             const SDL_TouchFingerEvent *event) {
     struct control_msg msg;
@@ -635,7 +637,7 @@ convert_mouse_button(const SDL_MouseButtonEvent *from, struct screen *screen,
     return true;
 }
 
-static void
+void
 input_manager_process_mouse_button(struct input_manager *im,
                                    const SDL_MouseButtonEvent *event) {
     bool control = im->control;
@@ -734,7 +736,7 @@ convert_mouse_wheel(const SDL_MouseWheelEvent *from, struct screen *screen,
     return true;
 }
 
-static void
+void
 input_manager_process_mouse_wheel(struct input_manager *im,
                                   const SDL_MouseWheelEvent *event) {
     struct control_msg msg;
@@ -744,46 +746,3 @@ input_manager_process_mouse_wheel(struct input_manager *im,
         }
     }
 }
-
-bool
-input_manager_handle_event(struct input_manager *im, SDL_Event *event) {
-    switch (event->type) {
-        case SDL_TEXTINPUT:
-            if (!im->control) {
-                return true;
-            }
-            input_manager_process_text_input(im, &event->text);
-            return true;
-        case SDL_KEYDOWN:
-        case SDL_KEYUP:
-            // some key events do not interact with the device, so process the
-            // event even if control is disabled
-            input_manager_process_key(im, &event->key);
-            return true;
-        case SDL_MOUSEMOTION:
-            if (!im->control) {
-                break;
-            }
-            input_manager_process_mouse_motion(im, &event->motion);
-            return true;
-        case SDL_MOUSEWHEEL:
-            if (!im->control) {
-                break;
-            }
-            input_manager_process_mouse_wheel(im, &event->wheel);
-            return true;
-        case SDL_MOUSEBUTTONDOWN:
-        case SDL_MOUSEBUTTONUP:
-            // some mouse events do not interact with the device, so process
-            // the event even if control is disabled
-            input_manager_process_mouse_button(im, &event->button);
-            return true;
-        case SDL_FINGERMOTION:
-        case SDL_FINGERDOWN:
-        case SDL_FINGERUP:
-            input_manager_process_touch(im, &event->tfinger);
-            return true;
-    }
-
-    return false;
-}

app/src/input_manager.h

@@ -16,7 +16,6 @@
 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
@@ -41,7 +40,28 @@ void
 input_manager_init(struct input_manager *im,
                    const struct scrcpy_options *options);
 
-bool
-input_manager_handle_event(struct input_manager *im, SDL_Event *event);
+void
+input_manager_process_text_input(struct input_manager *im,
+                                 const SDL_TextInputEvent *event);
+
+void
+input_manager_process_key(struct input_manager *im,
+                          const SDL_KeyboardEvent *event);
+
+void
+input_manager_process_mouse_motion(struct input_manager *im,
+                                   const SDL_MouseMotionEvent *event);
+
+void
+input_manager_process_touch(struct input_manager *im,
+                            const SDL_TouchFingerEvent *event);
+
+void
+input_manager_process_mouse_button(struct input_manager *im,
+                                   const SDL_MouseButtonEvent *event);
+
+void
+input_manager_process_mouse_wheel(struct input_manager *im,
+                                  const SDL_MouseWheelEvent *event);
 
 #endif

app/src/scrcpy.c

@@ -30,7 +30,7 @@
 #include "util/net.h"
 
 static struct server server;
-static struct screen screen;
+static struct screen screen = SCREEN_INITIALIZER;
 static struct fps_counter fps_counter;
 static struct video_buffer video_buffer;
 static struct stream stream;
@@ -42,7 +42,6 @@ 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,
 
@@ -174,6 +173,54 @@ handle_event(SDL_Event *event, const struct scrcpy_options *options) {
         case SDL_QUIT:
             LOGD("User requested to quit");
             return EVENT_RESULT_STOPPED_BY_USER;
+        case EVENT_NEW_FRAME:
+            if (!screen.has_frame) {
+                screen.has_frame = true;
+                // this is the very first frame, show the window
+                screen_show_window(&screen);
+            }
+            if (!screen_update_frame(&screen, &video_buffer)) {
+                return EVENT_RESULT_CONTINUE;
+            }
+            break;
+        case SDL_WINDOWEVENT:
+            screen_handle_window_event(&screen, &event->window);
+            break;
+        case SDL_TEXTINPUT:
+            if (!options->control) {
+                break;
+            }
+            input_manager_process_text_input(&input_manager, &event->text);
+            break;
+        case SDL_KEYDOWN:
+        case SDL_KEYUP:
+            // some key events do not interact with the device, so process the
+            // event even if control is disabled
+            input_manager_process_key(&input_manager, &event->key);
+            break;
+        case SDL_MOUSEMOTION:
+            if (!options->control) {
+                break;
+            }
+            input_manager_process_mouse_motion(&input_manager, &event->motion);
+            break;
+        case SDL_MOUSEWHEEL:
+            if (!options->control) {
+                break;
+            }
+            input_manager_process_mouse_wheel(&input_manager, &event->wheel);
+            break;
+        case SDL_MOUSEBUTTONDOWN:
+        case SDL_MOUSEBUTTONUP:
+            // some mouse events do not interact with the device, so process
+            // the event even if control is disabled
+            input_manager_process_mouse_button(&input_manager, &event->button);
+            break;
+        case SDL_FINGERMOTION:
+        case SDL_FINGERDOWN:
+        case SDL_FINGERUP:
+            input_manager_process_touch(&input_manager, &event->tfinger);
+            break;
         case SDL_DROPFILE: {
             if (!options->control) {
                 break;
@@ -195,16 +242,6 @@ handle_event(SDL_Event *event, const struct scrcpy_options *options) {
             break;
         }
     }
-
-    bool consumed = screen_handle_event(&screen, event);
-    if (consumed) {
-        goto end;
-    }
-
-    consumed = input_manager_handle_event(&input_manager, event);
-    (void) consumed;
-
-end:
     return EVENT_RESULT_CONTINUE;
 }
 
@@ -267,14 +304,6 @@ av_log_callback(void *avcl, int level, const char *fmt, va_list vl) {
     free(local_fmt);
 }
 
-static void
-video_buffer_on_frame_available(struct video_buffer *vb, void *userdata) {
-    (void) vb;
-    (void) userdata;
-
-    screen_on_frame_available(&screen);
-}
-
 bool
 scrcpy(const struct scrcpy_options *options) {
     if (!server_init(&server)) {
@@ -341,12 +370,8 @@ scrcpy(const struct scrcpy_options *options) {
         }
         fps_counter_initialized = true;
 
-        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)) {
+        if (!video_buffer_init(&video_buffer, &fps_counter,
+                               options->render_expired_frames)) {
             goto end;
         }
         video_buffer_initialized = true;
@@ -379,6 +404,13 @@ 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)) {
@@ -395,8 +427,6 @@ scrcpy(const struct scrcpy_options *options) {
         const char *window_title =
             options->window_title ? options->window_title : device_name;
 
-        screen_init(&screen, &video_buffer, &fps_counter);
-
         if (!screen_init_rendering(&screen, window_title, frame_size,
                                    options->always_on_top, options->window_x,
                                    options->window_y, options->window_width,
@@ -421,13 +451,6 @@ 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/screen.c

@@ -4,7 +4,6 @@
 #include <string.h>
 #include <SDL2/SDL.h>
 
-#include "events.h"
 #include "icon.xpm"
 #include "scrcpy.h"
 #include "tiny_xpm.h"
@@ -192,11 +191,8 @@ screen_update_content_rect(struct screen *screen) {
 }
 
 void
-screen_init(struct screen *screen, struct video_buffer *vb,
-            struct fps_counter *fps_counter) {
+screen_init(struct screen *screen) {
     *screen = (struct screen) SCREEN_INITIALIZER;
-    screen->vb = vb;
-    screen->fps_counter = fps_counter;
 }
 
 static inline SDL_Texture *
@@ -274,7 +270,7 @@ screen_init_rendering(struct screen *screen, const char *window_title,
                                           SDL_RENDERER_ACCELERATED);
     if (!screen->renderer) {
         LOGC("Could not create renderer: %s", SDL_GetError());
-        SDL_DestroyWindow(screen->window);
+        screen_destroy(screen);
         return false;
     }
 
@@ -284,8 +280,8 @@ screen_init_rendering(struct screen *screen, const char *window_title,
     LOGI("Renderer: %s", renderer_name ? renderer_name : "(unknown)");
 
     // starts with "opengl"
-    bool use_opengl = renderer_name && !strncmp(renderer_name, "opengl", 6);
-    if (use_opengl) {
+    screen->use_opengl = renderer_name && !strncmp(renderer_name, "opengl", 6);
+    if (screen->use_opengl) {
         struct sc_opengl *gl = &screen->gl;
         sc_opengl_init(gl);
 
@@ -305,7 +301,7 @@ screen_init_rendering(struct screen *screen, const char *window_title,
         } else {
             LOGI("Trilinear filtering disabled");
         }
-    } else if (mipmaps) {
+    } else {
         LOGD("Trilinear filtering disabled (not an OpenGL renderer)");
     }
 
@@ -322,8 +318,6 @@ screen_init_rendering(struct screen *screen, const char *window_title,
     screen->texture = create_texture(screen);
     if (!screen->texture) {
         LOGC("Could not create texture: %s", SDL_GetError());
-        SDL_DestroyRenderer(screen->renderer);
-        SDL_DestroyWindow(screen->window);
         screen_destroy(screen);
         return false;
     }
@@ -348,8 +342,12 @@ screen_destroy(struct screen *screen) {
     if (screen->texture) {
         SDL_DestroyTexture(screen->texture);
     }
-    SDL_DestroyRenderer(screen->renderer);
-    SDL_DestroyWindow(screen->window);
+    if (screen->renderer) {
+        SDL_DestroyRenderer(screen->renderer);
+    }
+    if (screen->window) {
+        SDL_DestroyWindow(screen->window);
+    }
 }
 
 static void
@@ -446,23 +444,19 @@ update_texture(struct screen *screen, const AVFrame *frame) {
             frame->data[2], frame->linesize[2]);
 
     if (screen->mipmaps) {
+        assert(screen->use_opengl);
         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) {
-    unsigned skipped;
-    const AVFrame *frame =
-        video_buffer_consumer_take_frame(screen->vb, &skipped);
-
-    fps_counter_add_skipped_frames(screen->fps_counter, skipped);
-    fps_counter_add_rendered_frame(screen->fps_counter);
-
+bool
+screen_update_frame(struct screen *screen, struct video_buffer *vb) {
+    const AVFrame *frame = video_buffer_take_rendering_frame(vb);
     struct size new_frame_size = {frame->width, frame->height};
     if (!prepare_for_frame(screen, new_frame_size)) {
+        sc_mutex_unlock(&vb->mutex);
         return false;
     }
     update_texture(screen, frame);
@@ -552,52 +546,31 @@ screen_resize_to_pixel_perfect(struct screen *screen) {
                                             content_size.height);
 }
 
-bool
-screen_handle_event(struct screen *screen, SDL_Event *event) {
-    switch (event->type) {
-        case EVENT_NEW_FRAME:
-            if (!screen->has_frame) {
-                screen->has_frame = true;
-                // this is the very first frame, show the window
-                screen_show_window(screen);
+void
+screen_handle_window_event(struct screen *screen,
+                           const SDL_WindowEvent *event) {
+    switch (event->event) {
+        case SDL_WINDOWEVENT_EXPOSED:
+            screen_render(screen, true);
+            break;
+        case SDL_WINDOWEVENT_SIZE_CHANGED:
+            screen_render(screen, true);
+            break;
+        case SDL_WINDOWEVENT_MAXIMIZED:
+            screen->maximized = true;
+            break;
+        case SDL_WINDOWEVENT_RESTORED:
+            if (screen->fullscreen) {
+                // On Windows, in maximized+fullscreen, disabling fullscreen
+                // mode unexpectedly triggers the "restored" then "maximized"
+                // events, leaving the window in a weird state (maximized
+                // according to the events, but not maximized visually).
+                break;
             }
-            bool ok = screen_update_frame(screen);
-            if (!ok) {
-                LOGW("Frame update failed\n");
-            }
-            return true;
-        case SDL_WINDOWEVENT:
-            if (!screen->has_frame) {
-                // Do nothing
-                return true;
-            }
-            switch (event->window.event) {
-                case SDL_WINDOWEVENT_EXPOSED:
-                    screen_render(screen, true);
-                    break;
-                case SDL_WINDOWEVENT_SIZE_CHANGED:
-                    screen_render(screen, true);
-                    break;
-                case SDL_WINDOWEVENT_MAXIMIZED:
-                    screen->maximized = true;
-                    break;
-                case SDL_WINDOWEVENT_RESTORED:
-                    if (screen->fullscreen) {
-                        // On Windows, in maximized+fullscreen, disabling
-                        // fullscreen mode unexpectedly triggers the "restored"
-                        // then "maximized" events, leaving the window in a
-                        // weird state (maximized according to the events, but
-                        // not maximized visually).
-                        break;
-                    }
-                    screen->maximized = false;
-                    apply_pending_resize(screen);
-                    break;
-            }
-            return true;
+            screen->maximized = false;
+            apply_pending_resize(screen);
+            break;
     }
-
-    return false;
 }
 
 struct point
@@ -655,15 +628,3 @@ screen_hidpi_scale_coords(struct screen *screen, int32_t *x, int32_t *y) {
     *x = (int64_t) *x * dw / ww;
     *y = (int64_t) *y * dh / wh;
 }
-
-void
-screen_on_frame_available(struct screen *screen) {
-    (void) screen;
-
-    static SDL_Event new_frame_event = {
-        .type = EVENT_NEW_FRAME,
-    };
-
-    // Post the event on the UI thread
-    SDL_PushEvent(&new_frame_event);
-}

app/src/screen.h

@@ -13,12 +13,10 @@
 struct video_buffer;
 
 struct screen {
-    struct video_buffer *vb;
-    struct fps_counter *fps_counter;
-
     SDL_Window *window;
     SDL_Renderer *renderer;
     SDL_Texture *texture;
+    bool use_opengl;
     struct sc_opengl gl;
     struct size frame_size;
     struct size content_size; // rotated frame_size
@@ -40,11 +38,10 @@ struct screen {
 };
 
 #define SCREEN_INITIALIZER { \
-    .vb = NULL, \
-    .fps_counter = NULL, \
     .window = NULL, \
     .renderer = NULL, \
     .texture = NULL, \
+    .use_opengl = false, \
     .gl = {0}, \
     .frame_size = { \
         .width = 0, \
@@ -75,8 +72,7 @@ struct screen {
 
 // initialize default values
 void
-screen_init(struct screen *screen, struct video_buffer *vb,
-            struct fps_counter *fps_counter);
+screen_init(struct screen *screen);
 
 // initialize screen, create window, renderer and texture (window is hidden)
 // window_x and window_y accept SC_WINDOW_POSITION_UNDEFINED
@@ -95,6 +91,10 @@ screen_show_window(struct screen *screen);
 void
 screen_destroy(struct screen *screen);
 
+// resize if necessary and write the rendered frame into the texture
+bool
+screen_update_frame(struct screen *screen, struct video_buffer *vb);
+
 // render the texture to the renderer
 //
 // Set the update_content_rect flag if the window or content size may have
@@ -118,9 +118,9 @@ screen_resize_to_pixel_perfect(struct screen *screen);
 void
 screen_set_rotation(struct screen *screen, unsigned rotation);
 
-// react to SDL events
-bool
-screen_handle_event(struct screen *screen, SDL_Event *event);
+// react to window events
+void
+screen_handle_window_event(struct screen *screen, const SDL_WindowEvent *event);
 
 // convert point from window coordinates to frame coordinates
 // x and y are expressed in pixels
@@ -141,9 +141,4 @@ screen_convert_drawable_to_frame_coords(struct screen *screen,
 void
 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_frame_available(struct screen *screen);
-
 #endif

app/src/server.c

@@ -375,6 +375,8 @@ server_init(struct server *server) {
     server->video_socket = INVALID_SOCKET;
     server->control_socket = INVALID_SOCKET;
 
+    server->port_range.first = 0;
+    server->port_range.last = 0;
     server->local_port = 0;
 
     server->tunnel_enabled = false;
@@ -408,6 +410,8 @@ run_wait_server(void *data) {
 bool
 server_start(struct server *server, const char *serial,
              const struct server_params *params) {
+    server->port_range = params->port_range;
+
     if (serial) {
         server->serial = strdup(serial);
         if (!server->serial) {

app/src/server.h

@@ -26,6 +26,7 @@ struct server {
     socket_t server_socket; // only used if !tunnel_forward
     socket_t video_socket;
     socket_t control_socket;
+    struct sc_port_range port_range;
     uint16_t local_port; // selected from port_range
     bool tunnel_enabled;
     bool tunnel_forward; // use "adb forward" instead of "adb reverse"

app/src/util/thread.c

@@ -61,7 +61,6 @@ sc_mutex_lock(sc_mutex *mutex) {
 void
 sc_mutex_unlock(sc_mutex *mutex) {
 #ifndef NDEBUG
-    assert(sc_mutex_held(mutex));
     mutex->locker = 0;
 #endif
     int r = SDL_UnlockMutex(mutex->mutex);

app/src/video_buffer.c

@@ -7,11 +7,12 @@
 #include "util/log.h"
 
 bool
-video_buffer_init(struct video_buffer *vb, bool wait_consumer,
-                  const struct video_buffer_callbacks *cbs,
-                  void *cbs_userdata) {
-    vb->producer_frame = av_frame_alloc();
-    if (!vb->producer_frame) {
+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) {
         goto error_0;
     }
 
@@ -20,8 +21,8 @@ video_buffer_init(struct video_buffer *vb, bool wait_consumer,
         goto error_1;
     }
 
-    vb->consumer_frame = av_frame_alloc();
-    if (!vb->consumer_frame) {
+    vb->rendering_frame = av_frame_alloc();
+    if (!vb->rendering_frame) {
         goto error_2;
     }
 
@@ -30,8 +31,8 @@ video_buffer_init(struct video_buffer *vb, bool wait_consumer,
         goto error_3;
     }
 
-    vb->wait_consumer = wait_consumer;
-    if (wait_consumer) {
+    vb->render_expired_frames = render_expired_frames;
+    if (render_expired_frames) {
         ok = sc_cond_init(&vb->pending_frame_consumed_cond);
         if (!ok) {
             sc_mutex_destroy(&vb->mutex);
@@ -46,107 +47,89 @@ video_buffer_init(struct video_buffer *vb, bool wait_consumer,
     // 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->consumer_frame);
+    av_frame_free(&vb->rendering_frame);
 error_2:
     av_frame_free(&vb->pending_frame);
 error_1:
-    av_frame_free(&vb->producer_frame);
+    av_frame_free(&vb->decoding_frame);
 error_0:
     return false;
 }
 
 void
 video_buffer_destroy(struct video_buffer *vb) {
-    if (vb->wait_consumer) {
+    if (vb->render_expired_frames) {
         sc_cond_destroy(&vb->pending_frame_consumed_cond);
     }
     sc_mutex_destroy(&vb->mutex);
-    av_frame_free(&vb->consumer_frame);
+    av_frame_free(&vb->rendering_frame);
     av_frame_free(&vb->pending_frame);
-    av_frame_free(&vb->producer_frame);
+    av_frame_free(&vb->decoding_frame);
 }
 
 static void
-video_buffer_swap_producer_frame(struct video_buffer *vb) {
+video_buffer_swap_decoding_frame(struct video_buffer *vb) {
     sc_mutex_assert(&vb->mutex);
-    AVFrame *tmp = vb->producer_frame;
-    vb->producer_frame = vb->pending_frame;
+    AVFrame *tmp = vb->decoding_frame;
+    vb->decoding_frame = vb->pending_frame;
     vb->pending_frame = tmp;
 }
 
 static void
-video_buffer_swap_consumer_frame(struct video_buffer *vb) {
+video_buffer_swap_rendering_frame(struct video_buffer *vb) {
     sc_mutex_assert(&vb->mutex);
-    AVFrame *tmp = vb->consumer_frame;
-    vb->consumer_frame = vb->pending_frame;
+    AVFrame *tmp = vb->rendering_frame;
+    vb->rendering_frame = vb->pending_frame;
     vb->pending_frame = tmp;
 }
 
 void
-video_buffer_producer_offer_frame(struct video_buffer *vb) {
+video_buffer_offer_decoded_frame(struct video_buffer *vb,
+                                 bool *previous_frame_skipped) {
     sc_mutex_lock(&vb->mutex);
-    if (vb->wait_consumer) {
+    if (vb->render_expired_frames) {
         // 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_producer_frame(vb);
-
-    bool skipped = !vb->pending_frame_consumed;
-    if (skipped) {
-        ++vb->skipped;
-    }
+    video_buffer_swap_decoding_frame(vb);
 
+    *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_consumer_take_frame(struct video_buffer *vb, unsigned *skipped) {
+video_buffer_take_rendering_frame(struct video_buffer *vb) {
     sc_mutex_lock(&vb->mutex);
     assert(!vb->pending_frame_consumed);
     vb->pending_frame_consumed = true;
 
-    video_buffer_swap_consumer_frame(vb);
+    fps_counter_add_rendered_frame(vb->fps_counter);
 
-    if (vb->wait_consumer) {
+    video_buffer_swap_rendering_frame(vb);
+
+    if (vb->render_expired_frames) {
         // 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);
 
-    // consumer_frame is only written from this thread, no need to lock
-    return vb->consumer_frame;
+    // rendering_frame is only written from this thread, no need to lock
+    return vb->rendering_frame;
 }
 
 void
 video_buffer_interrupt(struct video_buffer *vb) {
-    if (vb->wait_consumer) {
+    if (vb->render_expired_frames) {
         sc_mutex_lock(&vb->mutex);
         vb->interrupted = true;
         sc_mutex_unlock(&vb->mutex);

app/src/video_buffer.h

@@ -13,62 +13,53 @@ typedef struct AVFrame AVFrame;
 
 /**
  * There are 3 frames in memory:
- *  - 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)
+ *  - 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)
  *
- * The producer generates a frame into the producer_frame (it may takes time).
+ * The decoder decodes a packet into the decoding_frame (it may takes time).
  *
- * Once the frame is produced, it calls video_buffer_producer_offer_frame(),
- * which swaps the producer and pending frames.
+ * Once the frame is decoded, it calls video_buffer_offer_decoded_frame(),
+ * which swaps the decoding and pending frames.
  *
- * 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.
+ * 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.
  */
 
 struct video_buffer {
-    AVFrame *producer_frame;
+    AVFrame *decoding_frame;
     AVFrame *pending_frame;
-    AVFrame *consumer_frame;
+    AVFrame *rendering_frame;
 
     sc_mutex mutex;
-    bool wait_consumer; // never overwrite a pending frame if it is not consumed
+    bool render_expired_frames;
     bool interrupted;
 
     sc_cond pending_frame_consumed_cond;
     bool pending_frame_consumed;
 
-    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);
+    struct fps_counter *fps_counter;
 };
 
 bool
-video_buffer_init(struct video_buffer *vb, bool wait_consumer,
-                  const struct video_buffer_callbacks *cbs, void *cbs_userdata);
+video_buffer_init(struct video_buffer *vb, struct fps_counter *fps_counter,
+                  bool render_expired_frames);
 
 void
 video_buffer_destroy(struct video_buffer *vb);
 
-// set the producer frame as ready for consuming
+// set the decoded frame as ready for rendering
+// the output flag is set to report whether the previous frame has been skipped
 void
-video_buffer_producer_offer_frame(struct video_buffer *vb);
+video_buffer_offer_decoded_frame(struct video_buffer *vb,
+                                 bool *previous_frame_skipped);
 
-// mark the consumer frame as consumed and return it
+// mark the rendering 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_consumer_take_frame(struct video_buffer *vb, unsigned *skipped);
+video_buffer_take_rendering_frame(struct video_buffer *vb);
 
 // wake up and avoid any blocking call
 void

meson.build

@@ -4,7 +4,6 @@ project('scrcpy', 'c',
         default_options: [
             'c_std=c11',
             'warning_level=2',
-            'b_ndebug=if-release',
         ])
 
 if get_option('compile_app')