scale_filter

Make the decoder independant of the SDL event mechanism.

app/scrcpy.1

@@ -167,6 +167,13 @@ Set the initial display rotation. Possibles values are 0, 1, 2 and 3. Each incre
 .BI "\-s, \-\-serial " number
 The device serial number. Mandatory only if several devices are connected to adb.
 
+.TP
+.BI "\-\-scale\-filter filter
+Supported filters are "none" and "trilinear".
+
+Trilinear filtering is only available if the renderer is OpenGL 3.0+ or OpenGL
+ES 2.0+.
+
 .TP
 .BI "\-\-shortcut\-mod " key[+...]][,...]
 Specify the modifiers to use for scrcpy shortcuts. Possible keys are "lctrl", "rctrl", "lalt", "ralt", "lsuper" and "rsuper".

app/src/cli.c

@@ -103,11 +103,6 @@ scrcpy_print_usage(const char *arg0) {
         "    --no-key-repeat\n"
         "        Do not forward repeated key events when a key is held down.\n"
         "\n"
-        "    --no-mipmaps\n"
-        "        If the renderer is OpenGL 3.0+ or OpenGL ES 2.0+, then\n"
-        "        mipmaps are automatically generated to improve downscaling\n"
-        "        quality. This option disables the generation of mipmaps.\n"
-        "\n"
         "    -p, --port port[:port]\n"
         "        Set the TCP port (range) used by the client to listen.\n"
         "        Default is %d:%d.\n"
@@ -154,6 +149,11 @@ scrcpy_print_usage(const char *arg0) {
         "        The device serial number. Mandatory only if several devices\n"
         "        are connected to adb.\n"
         "\n"
+        "    --scale-filter filter\n"
+        "        Supported filters are \"none\" and \"trilinear\".\n"
+        "        Trilinear filtering is only available if the renderer is\n"
+        "        OpenGL 3.0+ or OpenGL ES 2.0+.\n"
+        "\n"
         "    --shortcut-mod key[+...]][,...]\n"
         "        Specify the modifiers to use for scrcpy shortcuts.\n"
         "        Possible keys are \"lctrl\", \"rctrl\", \"lalt\", \"ralt\",\n"
@@ -641,6 +641,21 @@ guess_record_format(const char *filename) {
     return 0;
 }
 
+static bool
+parse_scale_filter(const char *optarg, enum sc_scale_filter *filter) {
+    if (!strcmp(optarg, "none")) {
+        *filter = SC_SCALE_FILTER_NONE;
+        return true;
+    }
+    if (!strcmp(optarg, "trilinear")) {
+        *filter = SC_SCALE_FILTER_TRILINEAR;
+        return true;
+    }
+    LOGE("Unsupported scale filter: %s "
+         "(expected \"none\" or \"trilinear\")", optarg);
+    return false;
+}
+
 #define OPT_RENDER_EXPIRED_FRAMES  1000
 #define OPT_WINDOW_TITLE           1001
 #define OPT_PUSH_TARGET            1002
@@ -667,6 +682,7 @@ guess_record_format(const char *filename) {
 #define OPT_FORWARD_ALL_CLICKS     1023
 #define OPT_LEGACY_PASTE           1024
 #define OPT_ENCODER_NAME           1025
+#define OPT_SCALE_FILTER           1026
 
 bool
 scrcpy_parse_args(struct scrcpy_cli_args *args, int argc, char *argv[]) {
@@ -703,6 +719,7 @@ scrcpy_parse_args(struct scrcpy_cli_args *args, int argc, char *argv[]) {
         {"render-expired-frames",  no_argument,       NULL,
                                                   OPT_RENDER_EXPIRED_FRAMES},
         {"rotation",               required_argument, NULL, OPT_ROTATION},
+        {"scale-filter",           required_argument, NULL, OPT_SCALE_FILTER},
         {"serial",                 required_argument, NULL, 's'},
         {"shortcut-mod",           required_argument, NULL, OPT_SHORTCUT_MOD},
         {"show-touches",           no_argument,       NULL, 't'},
@@ -857,7 +874,9 @@ scrcpy_parse_args(struct scrcpy_cli_args *args, int argc, char *argv[]) {
                 opts->render_driver = optarg;
                 break;
             case OPT_NO_MIPMAPS:
-                opts->mipmaps = false;
+                LOGW("Deprecated option --no-mipmaps. "
+                     "Use --scale-filter=none instead.");
+                opts->scale_filter = SC_SCALE_FILTER_NONE;
                 break;
             case OPT_NO_KEY_REPEAT:
                 opts->forward_key_repeat = false;
@@ -885,6 +904,11 @@ scrcpy_parse_args(struct scrcpy_cli_args *args, int argc, char *argv[]) {
             case OPT_LEGACY_PASTE:
                 opts->legacy_paste = true;
                 break;
+            case OPT_SCALE_FILTER:
+                if (!parse_scale_filter(optarg, &opts->scale_filter)) {
+                    return false;
+                }
+                break;
             default:
                 // getopt prints the error message on stderr
                 return false;

app/src/decoder.c

@@ -2,7 +2,6 @@
 
 #include <libavformat/avformat.h>
 #include <libavutil/time.h>
-#include <SDL2/SDL_events.h>
 #include <unistd.h>
 
 #include "events.h"
@@ -14,12 +13,26 @@
 // 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 callback will consume this frame
+        return;
+    }
+
+    decoder->cbs->on_new_frame(decoder, decoder->cbs_userdata);
 }
 
 void
-decoder_init(struct decoder *decoder, struct video_buffer *vb) {
+decoder_init(struct decoder *decoder, struct video_buffer *vb,
+             const struct decoder_callbacks *cbs, void *cbs_userdata) {
     decoder->video_buffer = vb;
+
+    assert(cbs);
+    assert(cbs->on_new_frame);
+    decoder->cbs = cbs;
+    decoder->cbs_userdata = cbs_userdata;
 }
 
 bool
@@ -56,7 +69,7 @@ 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/decoder.h

@@ -11,10 +11,20 @@ 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);
 };
 
 void
-decoder_init(struct decoder *decoder, struct video_buffer *vb);
+decoder_init(struct decoder *decoder, struct video_buffer *vb,
+             const struct decoder_callbacks *cbs, void *cbs_userdata);
 
 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_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

@@ -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:

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

app/src/scrcpy.c

@@ -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,
 
@@ -268,11 +267,11 @@ av_log_callback(void *avcl, int level, const char *fmt, va_list vl) {
 }
 
 static void
-video_buffer_on_frame_available(struct video_buffer *vb, void *userdata) {
-    (void) vb;
+decoder_on_new_frame(struct decoder *decoder, void *userdata) {
+    (void) decoder;
     (void) userdata;
 
-    screen_on_frame_available(&screen);
+    screen_on_new_frame(&screen);
 }
 
 bool
@@ -341,12 +340,8 @@ 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;
@@ -359,7 +354,11 @@ scrcpy(const struct scrcpy_options *options) {
             file_handler_initialized = true;
         }
 
-        decoder_init(&decoder, &video_buffer);
+        static const struct decoder_callbacks decoder_cbs = {
+            .on_new_frame = decoder_on_new_frame,
+        };
+
+        decoder_init(&decoder, &video_buffer, &decoder_cbs, NULL);
         dec = &decoder;
     }
 
@@ -379,6 +378,13 @@ 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)) {
@@ -395,14 +401,14 @@ 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);
+        screen_init(&screen, &video_buffer);
 
         if (!screen_init_rendering(&screen, window_title, frame_size,
                                    options->always_on_top, options->window_x,
                                    options->window_y, options->window_width,
                                    options->window_height,
                                    options->window_borderless,
-                                   options->rotation, options->mipmaps)) {
+                                   options->rotation, options->scale_filter)) {
             goto end;
         }
 
@@ -421,13 +427,6 @@ 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/scrcpy.h

@@ -41,6 +41,11 @@ struct sc_port_range {
     uint16_t last;
 };
 
+enum sc_scale_filter {
+    SC_SCALE_FILTER_NONE,
+    SC_SCALE_FILTER_TRILINEAR, // mipmaps
+};
+
 #define SC_WINDOW_POSITION_UNDEFINED (-0x8000)
 
 struct scrcpy_options {
@@ -56,6 +61,7 @@ struct scrcpy_options {
     enum sc_record_format record_format;
     struct sc_port_range port_range;
     struct sc_shortcut_mods shortcut_mods;
+    enum sc_scale_filter scale_filter;
     uint16_t max_size;
     uint32_t bit_rate;
     uint16_t max_fps;
@@ -75,7 +81,6 @@ struct scrcpy_options {
     bool render_expired_frames;
     bool prefer_text;
     bool window_borderless;
-    bool mipmaps;
     bool stay_awake;
     bool force_adb_forward;
     bool disable_screensaver;
@@ -103,6 +108,7 @@ struct scrcpy_options {
         .data = {SC_MOD_LALT, SC_MOD_LSUPER}, \
         .count = 2, \
     }, \
+    .scale_filter = SC_SCALE_FILTER_TRILINEAR, \
     .max_size = DEFAULT_MAX_SIZE, \
     .bit_rate = DEFAULT_BIT_RATE, \
     .max_fps = 0, \
@@ -122,7 +128,6 @@ struct scrcpy_options {
     .render_expired_frames = false, \
     .prefer_text = false, \
     .window_borderless = false, \
-    .mipmaps = true, \
     .stay_awake = false, \
     .force_adb_forward = false, \
     .disable_screensaver = false, \

app/src/screen.c

@@ -6,7 +6,6 @@
 
 #include "events.h"
 #include "icon.xpm"
-#include "scrcpy.h"
 #include "tiny_xpm.h"
 #include "video_buffer.h"
 #include "util/log.h"
@@ -192,11 +191,9 @@ 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, struct video_buffer *vb) {
     *screen = (struct screen) SCREEN_INITIALIZER;
     screen->vb = vb;
-    screen->fps_counter = fps_counter;
 }
 
 static inline SDL_Texture *
@@ -231,7 +228,7 @@ screen_init_rendering(struct screen *screen, const char *window_title,
                       struct size frame_size, bool always_on_top,
                       int16_t window_x, int16_t window_y, uint16_t window_width,
                       uint16_t window_height, bool window_borderless,
-                      uint8_t rotation, bool mipmaps) {
+                      uint8_t rotation, enum sc_scale_filter scale_filter) {
     screen->frame_size = frame_size;
     screen->rotation = rotation;
     if (rotation) {
@@ -285,6 +282,7 @@ screen_init_rendering(struct screen *screen, const char *window_title,
 
     // starts with "opengl"
     bool use_opengl = renderer_name && !strncmp(renderer_name, "opengl", 6);
+    bool mipmaps = scale_filter == SC_SCALE_FILTER_TRILINEAR;
     if (use_opengl) {
         struct sc_opengl *gl = &screen->gl;
         sc_opengl_init(gl);
@@ -454,13 +452,7 @@ update_texture(struct screen *screen, const AVFrame *frame) {
 
 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);
-
+    const AVFrame *frame = video_buffer_take_rendering_frame(screen->vb);
     struct size new_frame_size = {frame->width, frame->height};
     if (!prepare_for_frame(screen, new_frame_size)) {
         return false;
@@ -657,7 +649,7 @@ screen_hidpi_scale_coords(struct screen *screen, int32_t *x, int32_t *y) {
 }
 
 void
-screen_on_frame_available(struct screen *screen) {
+screen_on_new_frame(struct screen *screen) {
     (void) screen;
 
     static SDL_Event new_frame_event = {

app/src/screen.h

@@ -9,13 +9,12 @@
 
 #include "coords.h"
 #include "opengl.h"
+#include "scrcpy.h"
 
 struct video_buffer;
 
 struct screen {
     struct video_buffer *vb;
-    struct fps_counter *fps_counter;
-
     SDL_Window *window;
     SDL_Renderer *renderer;
     SDL_Texture *texture;
@@ -41,7 +40,6 @@ struct screen {
 
 #define SCREEN_INITIALIZER { \
     .vb = NULL, \
-    .fps_counter = NULL, \
     .window = NULL, \
     .renderer = NULL, \
     .texture = NULL, \
@@ -75,8 +73,7 @@ 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, struct video_buffer *vb);
 
 // initialize screen, create window, renderer and texture (window is hidden)
 // window_x and window_y accept SC_WINDOW_POSITION_UNDEFINED
@@ -85,7 +82,7 @@ screen_init_rendering(struct screen *screen, const char *window_title,
                       struct size frame_size, bool always_on_top,
                       int16_t window_x, int16_t window_y, uint16_t window_width,
                       uint16_t window_height, bool window_borderless,
-                      uint8_t rotation, bool mipmaps);
+                      uint8_t rotation, enum sc_scale_filter scale_filter);
 
 // show the window
 void
@@ -144,6 +141,6 @@ 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_frame_available(struct screen *screen);
+screen_on_new_frame(struct screen *screen);
 
 #endif

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