scrcpy/app/src/video_buffer.c

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#include "video_buffer.h"
#include <SDL2/SDL_assert.h>
#include <SDL2/SDL_mutex.h>
#include <libavutil/avutil.h>
#include <libavformat/avformat.h>
#include "config.h"
#include "lock_util.h"
#include "log.h"
SDL_bool video_buffer_init(struct video_buffer *vb) {
if (!(vb->decoding_frame = av_frame_alloc())) {
goto error_0;
}
if (!(vb->rendering_frame = av_frame_alloc())) {
goto error_1;
}
if (!(vb->mutex = SDL_CreateMutex())) {
goto error_2;
}
#ifndef SKIP_FRAMES
if (!(vb->rendering_frame_consumed_cond = SDL_CreateCond())) {
SDL_DestroyMutex(vb->mutex);
goto error_2;
}
vb->interrupted = SDL_FALSE;
#endif
// there is initially no rendering frame, so consider it has already been
// consumed
vb->rendering_frame_consumed = SDL_TRUE;
fps_counter_init(&vb->fps_counter);
return SDL_TRUE;
error_2:
av_frame_free(&vb->rendering_frame);
error_1:
av_frame_free(&vb->decoding_frame);
error_0:
return SDL_FALSE;
}
void video_buffer_destroy(struct video_buffer *vb) {
#ifndef SKIP_FRAMES
SDL_DestroyCond(vb->rendering_frame_consumed_cond);
#endif
SDL_DestroyMutex(vb->mutex);
av_frame_free(&vb->rendering_frame);
av_frame_free(&vb->decoding_frame);
}
static void video_buffer_swap_frames(struct video_buffer *vb) {
AVFrame *tmp = vb->decoding_frame;
vb->decoding_frame = vb->rendering_frame;
vb->rendering_frame = tmp;
}
SDL_bool video_buffer_offer_decoded_frame(struct video_buffer *vb) {
mutex_lock(vb->mutex);
#ifndef SKIP_FRAMES
// if SKIP_FRAMES is disabled, then the decoder must wait for the current
// frame to be consumed
while (!vb->rendering_frame_consumed && !vb->interrupted) {
cond_wait(vb->rendering_frame_consumed_cond, vb->mutex);
}
#else
if (vb->fps_counter.started && !vb->rendering_frame_consumed) {
fps_counter_add_skipped_frame(&vb->fps_counter);
}
#endif
video_buffer_swap_frames(vb);
SDL_bool previous_frame_consumed = vb->rendering_frame_consumed;
vb->rendering_frame_consumed = SDL_FALSE;
mutex_unlock(vb->mutex);
return previous_frame_consumed;
}
const AVFrame *video_buffer_consume_rendered_frame(struct video_buffer *vb) {
SDL_assert(!vb->rendering_frame_consumed);
vb->rendering_frame_consumed = SDL_TRUE;
if (vb->fps_counter.started) {
fps_counter_add_rendered_frame(&vb->fps_counter);
}
#ifndef SKIP_FRAMES
// if SKIP_FRAMES is disabled, then notify the decoder the current frame is
// consumed, so that it may push a new one
cond_signal(vb->rendering_frame_consumed_cond);
#endif
return vb->rendering_frame;
}
void video_buffer_interrupt(struct video_buffer *vb) {
#ifdef SKIP_FRAMES
(void) vb; // unused
#else
mutex_lock(vb->mutex);
vb->interrupted = SDL_TRUE;
mutex_unlock(vb->mutex);
// wake up blocking wait
cond_signal(vb->rendering_frame_consumed_cond);
#endif
}