scrcpy/app/src/decoder.c

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C
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#include "decoder.h"
#include <libavformat/avformat.h>
#include <libavutil/time.h>
#include <SDL2/SDL_events.h>
#include <SDL2/SDL_mutex.h>
#include <SDL2/SDL_thread.h>
#include <unistd.h>
#include "config.h"
#include "events.h"
#include "frames.h"
#include "lock_util.h"
#include "log.h"
#include "recorder.h"
#define BUFSIZE 0x10000
static inline uint64_t from_be(uint8_t *b, int size)
{
uint64_t x = 0;
int i;
for (i = 0; i < size; i += 1) {
x <<= 8;
x |= b[i];
}
return x;
}
#define HEADER_SIZE 16
static int read_packet(void *opaque, uint8_t *buf, int buf_size) {
struct decoder *decoder = opaque;
uint8_t header[HEADER_SIZE];
int remaining;
int ret;
remaining = decoder->remaining;
if (remaining == 0) {
// FIXME what if only part of the header is available?
ret = net_recv(decoder->video_socket, header, HEADER_SIZE);
if (ret <= 0)
return ret;
decoder->pts = from_be(header, 8);
remaining = from_be(header + 12, 4);
}
if (buf_size > remaining)
buf_size = remaining;
ret = net_recv(decoder->video_socket, buf, buf_size);
if (ret <= 0)
return ret;
remaining -= ret;
decoder->remaining = remaining;
return ret;
}
// set the decoded frame as ready for rendering, and notify
static void push_frame(struct decoder *decoder) {
SDL_bool previous_frame_consumed = frames_offer_decoded_frame(decoder->frames);
if (!previous_frame_consumed) {
// 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);
}
static void notify_stopped(void) {
SDL_Event stop_event;
stop_event.type = EVENT_DECODER_STOPPED;
SDL_PushEvent(&stop_event);
}
static int run_decoder(void *data) {
struct decoder *decoder = data;
AVCodec *codec = avcodec_find_decoder(AV_CODEC_ID_H264);
if (!codec) {
LOGE("H.264 decoder not found");
goto run_end;
}
AVCodecContext *codec_ctx = avcodec_alloc_context3(codec);
if (!codec_ctx) {
LOGC("Could not allocate decoder context");
goto run_end;
}
if (avcodec_open2(codec_ctx, codec, NULL) < 0) {
LOGE("Could not open H.264 codec");
goto run_finally_free_codec_ctx;
}
AVFormatContext *format_ctx = avformat_alloc_context();
if (!format_ctx) {
LOGC("Could not allocate format context");
goto run_finally_close_codec;
}
unsigned char *buffer = av_malloc(BUFSIZE);
if (!buffer) {
LOGC("Could not allocate buffer");
goto run_finally_free_format_ctx;
}
AVIOContext *avio_ctx = avio_alloc_context(buffer, BUFSIZE, 0, decoder, read_packet, NULL, NULL);
if (!avio_ctx) {
LOGC("Could not allocate avio context");
// avformat_open_input takes ownership of 'buffer'
// so only free the buffer before avformat_open_input()
av_free(buffer);
goto run_finally_free_format_ctx;
}
format_ctx->pb = avio_ctx;
if (avformat_open_input(&format_ctx, NULL, NULL, NULL) < 0) {
LOGE("Could not open video stream");
goto run_finally_free_avio_ctx;
}
if (decoder->recorder &&
!recorder_open(decoder->recorder, codec)) {
LOGE("Could not open recorder");
goto run_finally_close_input;
}
AVPacket packet;
av_init_packet(&packet);
packet.data = NULL;
packet.size = 0;
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while (!av_read_frame(format_ctx, &packet)) {
if (decoder->recorder) {
packet.pts = decoder->pts;
// no need to rescale with av_packet_rescale_ts(), the timestamps
// are in microseconds both in input and output
if (!recorder_write(decoder->recorder, &packet)) {
LOGE("Could not write frame to output file");
av_packet_unref(&packet);
goto run_quit;
}
}
// the new decoding/encoding API has been introduced by:
// <http://git.videolan.org/?p=ffmpeg.git;a=commitdiff;h=7fc329e2dd6226dfecaa4a1d7adf353bf2773726>
#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(57, 37, 0)
int ret;
if ((ret = avcodec_send_packet(codec_ctx, &packet)) < 0) {
LOGE("Could not send video packet: %d", ret);
goto run_quit;
}
ret = avcodec_receive_frame(codec_ctx, decoder->frames->decoding_frame);
if (!ret) {
// a frame was received
push_frame(decoder);
} else if (ret != AVERROR(EAGAIN)) {
LOGE("Could not receive video frame: %d", ret);
av_packet_unref(&packet);
goto run_quit;
}
#else
while (packet.size > 0) {
int got_picture;
int len = avcodec_decode_video2(codec_ctx, decoder->frames->decoding_frame, &got_picture, &packet);
if (len < 0) {
LOGE("Could not decode video packet: %d", len);
av_packet_unref(&packet);
goto run_quit;
}
if (got_picture) {
push_frame(decoder);
}
packet.size -= len;
packet.data += len;
}
#endif
av_packet_unref(&packet);
if (avio_ctx->eof_reached) {
break;
}
}
LOGD("End of frames");
run_quit:
if (decoder->recorder) {
recorder_close(decoder->recorder);
}
run_finally_close_input:
avformat_close_input(&format_ctx);
run_finally_free_avio_ctx:
av_freep(&avio_ctx);
run_finally_free_format_ctx:
avformat_free_context(format_ctx);
run_finally_close_codec:
avcodec_close(codec_ctx);
run_finally_free_codec_ctx:
avcodec_free_context(&codec_ctx);
notify_stopped();
run_end:
return 0;
}
void decoder_init(struct decoder *decoder, struct frames *frames,
socket_t video_socket, struct recorder *recorder) {
decoder->frames = frames;
decoder->video_socket = video_socket;
decoder->recorder = recorder;
}
SDL_bool decoder_start(struct decoder *decoder) {
LOGD("Starting decoder thread");
decoder->thread = SDL_CreateThread(run_decoder, "video_decoder", decoder);
if (!decoder->thread) {
LOGC("Could not start decoder thread");
return SDL_FALSE;
}
return SDL_TRUE;
}
void decoder_stop(struct decoder *decoder) {
frames_stop(decoder->frames);
}
void decoder_join(struct decoder *decoder) {
SDL_WaitThread(decoder->thread, NULL);
}