int Decoder::decode_frame(AVFrame *frame) {
Decoder *d = this;
int got_frame = 0;
do {
int ret = -1;
if (d->queue->abort_request)
return -1;
if (!d->packet_pending || d->queue->serial != d->pkt_serial) {
AVPacket pkt;
do {
if (d->queue->nb_packets == 0)
d->empty_queue_cond ->signal();
if (d->queue->get(&pkt, 1, &d->pkt_serial) < 0)
return -1;
if (pkt.data == flush_pkt.data) {
avcodec_flush_buffers(d->avctx);
d->finished = 0;
d->next_pts = d->start_pts;
d->next_pts_tb = d->start_pts_tb;
}
} while (pkt.data == flush_pkt.data || d->queue->serial != d->pkt_serial);
av_free_packet(&d->pkt);
d->pkt_temp = d->pkt = pkt;
d->packet_pending = 1;
}
switch (d->avctx->codec_type) {
case AVMEDIA_TYPE_VIDEO:
ret = avcodec_decode_video2(d->avctx, frame, &got_frame, &d->pkt_temp);
if (got_frame) {
if (gOptions.decoder_reorder_pts == -1) {
frame->pts = av_frame_get_best_effort_timestamp(frame);
} else if (gOptions.decoder_reorder_pts) {
frame->pts = frame->pkt_pts;
} else {
frame->pts = frame->pkt_dts;
}
}
break;
case AVMEDIA_TYPE_AUDIO:
ret = avcodec_decode_audio4(d->avctx, frame, &got_frame, &d->pkt_temp);
if (got_frame) {
AVRational tb = (AVRational){1, frame->sample_rate};
if (frame->pts != AV_NOPTS_VALUE)
frame->pts = av_rescale_q(frame->pts, d->avctx->time_base, tb);
else if (frame->pkt_pts != AV_NOPTS_VALUE)
frame->pts = av_rescale_q(frame->pkt_pts, av_codec_get_pkt_timebase(d->avctx), tb);
else if (d->next_pts != AV_NOPTS_VALUE)
frame->pts = av_rescale_q(d->next_pts, d->next_pts_tb, tb);
if (frame->pts != AV_NOPTS_VALUE) {
d->next_pts = frame->pts + frame->nb_samples;
d->next_pts_tb = tb;
}
}
break;
case AVMEDIA_TYPE_SUBTITLE:
{
AVSubtitle *sub = (AVSubtitle*) frame;
ret = avcodec_decode_subtitle2(d->avctx, sub, &got_frame, &d->pkt_temp);
}
break;
}
if (ret < 0) {
d->packet_pending = 0;
} else {
d->pkt_temp.dts =
d->pkt_temp.pts = AV_NOPTS_VALUE;
if (d->pkt_temp.data) {
if (d->avctx->codec_type != AVMEDIA_TYPE_AUDIO)
ret = d->pkt_temp.size;
d->pkt_temp.data += ret;
d->pkt_temp.size -= ret;
if (d->pkt_temp.size <= 0)
d->packet_pending = 0;
} else {
if (!got_frame) {
d->packet_pending = 0;
d->finished = d->pkt_serial;
}
}
}
} while (!got_frame && !d->finished);
return got_frame;
}
int Decoder::decodeFrame(AVFrame *frame, AVSubtitle *sub) {
int got_frame = 0;
do {
int ret = -1;
// 如果处于舍弃状态，则直接返回
if (queue->isAbort()) {
return -1;
}
// 如果当前没有包在等待，获取队列的序列不相同，取出下一阵
if (!packet_pending || queue->serial != pkt_serial) {
AVPacket pkt;
do {
// 队列为空
if (queue->isEmpty()) {
CondSignal(empty_queue_cond);
}
// 获取裸数据
if (queue->get(&pkt, 1, &pkt_serial) < 0) {
return -1;
}
// 刷新数据
if (pkt.data == flush_pkt->data) {
avcodec_flush_buffers(avctx);
finished = 0;
next_pts = start_pts;
next_pts_tb = start_pts_tb;
}
} while (pkt.data == flush_pkt->data || queue->serial != pkt_serial);
av_packet_unref(&this->pkt);
this->pkt_temp = this->pkt_temp = pkt;
packet_pending = 1;
}
// 根据解码器类型判断是音频还是视频
switch (avctx->codec_type) {
case AVMEDIA_TYPE_VIDEO:
// 视频解码
ret = avcodec_decode_video2(avctx, frame, &got_frame, &pkt_temp);
// 解码成功，更新时间戳
if (got_frame) {
if (reorderPts == -1) {
frame->pts = av_frame_get_best_effort_timestamp(frame);
} else if (!reorderPts) {
frame->pts = frame->pkt_dts;
}
}
break;
case AVMEDIA_TYPE_AUDIO:
// 音频解码
ret = avcodec_decode_audio4(avctx, frame, &got_frame, &pkt_temp);
if (got_frame) {
AVRational tb = (AVRational) {1, frame->sample_rate};
// 更新帧时间戳
if (frame->pts != AV_NOPTS_VALUE) {
frame->pts = av_rescale_q(frame->pts, av_codec_get_pkt_timebase(avctx), tb);
} else if (next_pts != AV_NOPTS_VALUE) {
frame->pts = av_rescale_q(next_pts, next_pts_tb, tb);
}
// 更新下一帧时间戳
if (frame->pts != AV_NOPTS_VALUE) {
next_pts = frame->pts + frame->nb_samples;
next_pts_tb = tb;
}
}
break;
}
// 判断是否解码成功
if (ret < 0) {
packet_pending = 0;
} else {
pkt_temp.dts = pkt_temp.pts = AV_NOPTS_VALUE;
if (pkt_temp.data) {
if (avctx->codec_type != AVMEDIA_TYPE_AUDIO) {
ret = pkt_temp.size;
}
pkt_temp.data += ret;
pkt_temp.size -= ret;
if (pkt_temp.size <= 0) {
packet_pending = 0;
}
} else {
if (!got_frame) {
packet_pending = 0;
finished = pkt_serial;
}
}
}
} while (!got_frame && !finished);
return got_frame;
}
