EXPORT int start_bitstream (void *actx)
{
int ret = 0;
struct lsInput* input = NULL;
struct liveStream *ctx = (struct liveStream *)actx;
AVPacket packet;
while(1)
{
input = get_best_input(ctx);
if(!input)
{
ret = 0;
break;
}
ret = get_input_packet(input,&packet);
if (ret == AVERROR(EAGAIN))
{
continue;
}
else if (ret == AVERROR_EOF)
{
output_packet(input,NULL);
input->eof_reached = 1;
continue;
}
if(ret < 0)
{
av_log(NULL,AV_LOG_ERROR,"No Input packet %x\n",ret);
break;
}
ret = av_interleaved_write_frame(ctx->oc, &packet);
}
return ret;
}
EXPORT int start_capture(void *actx)
{
struct liveStream *ctx = (struct liveStream *)actx;
int got_frame;
int ret;
AVPacket packet;
AVFormatContext *ic;
long long start_time;
struct lsInput* input = NULL;
AVRational av_time_base_q = {1, AV_TIME_BASE};
if(!ctx)
{
ret = -1;
goto end;
}
while(1)
{
AVCodecContext *dec_ctx = NULL;
input = get_best_input(ctx);
if(!input)
{
continue;
}
dec_ctx = input->dec_ctx;
ic = input->ic;
if (ic->start_time != AV_NOPTS_VALUE)
start_time = ic->start_time;
ret = get_input_packet(input,&packet);
if (ret == AVERROR(EAGAIN))
{
continue;
}
else if (ret == AVERROR_EOF)
{
output_packet(input,NULL);
input->eof_reached = 1;
continue;
}
if(ret < 0)
{
av_log(NULL,AV_LOG_ERROR,"No Input packet %x\n",ret);
break;
}
if(input->id != 1)
{
if (packet.pts != AV_NOPTS_VALUE)
{
packet.pts -= av_rescale_q(start_time, av_time_base_q, ic->streams[0]->time_base);
}
if (packet.dts != AV_NOPTS_VALUE)
packet.dts -= av_rescale_q(start_time, av_time_base_q, ic->streams[0]->time_base);
}
if(packet.stream_index == 0)
{
ret = avcodec_decode_video2(dec_ctx, input->InFrame, &got_frame, &packet);
if (ret < 0)
{
av_log(NULL, AV_LOG_ERROR, "Error decoding video\n");
goto end;
}
if(!got_frame)
continue;
}
else
{
continue;
}
av_free_packet(&packet);
input->InFrame->pts = av_frame_get_best_effort_timestamp(input->InFrame);
take_filter_lock(&ctx->filter_lock);
if (av_buffersrc_add_frame_flags(input->in_filter, input->InFrame, AV_BUFFERSRC_FLAG_PUSH) < 0)
{
av_log(NULL, AV_LOG_ERROR,
"Error while feeding the filtergraph\n");
}
give_filter_lock(&ctx->filter_lock);
reap_filter(ctx);
}
av_frame_unref(input->InFrame);
end:
return ret;
}
/*
* Return
* - 0 -- one packet was read and processed
* - AVERROR(EAGAIN) -- no packets were available for selected file,
* this function should be called again
* - AVERROR_EOF -- this function should not be called again
*/
static int process_input(int file_index)
{
InputFile *ifile = input_files[file_index];
AVFormatContext *is;
InputStream *ist;
AVPacket pkt;
int ret, i, j;
is = ifile->ctx;
// ****<< Capture a frame: audio/video/subtitle
ret = get_input_packet(ifile, &pkt); // ****<< Call stack: av_read_frame() --> read_frame_internal() --> ff_read_packet() --> s->iformat->read_packet(s, pkt); --> dshow_read_frame();
if (ret == AVERROR(EAGAIN)) {
ifile->eagain = 1;
return ret;
}
if (ret < 0) {
if (ret != AVERROR_EOF) {
print_error(is->filename, ret);
if (exit_on_error)
exit_program(1);
}
ifile->eof_reached = 1;
for (i = 0; i < ifile->nb_streams; i++) {
ist = input_streams[ifile->ist_index + i];
if (ist->decoding_needed)
output_packet(ist, NULL);
/* mark all outputs that don't go through lavfi as finished */
for (j = 0; j < nb_output_streams; j++) {
OutputStream *ost = output_streams[j];
if (ost->source_index == ifile->ist_index + i &&
(ost->stream_copy || ost->enc->type == AVMEDIA_TYPE_SUBTITLE))
close_output_stream(ost);
}
}
return AVERROR(EAGAIN);
}
reset_eagain();
if (do_pkt_dump) {
av_pkt_dump_log2(NULL, AV_LOG_DEBUG, &pkt, do_hex_dump,
is->streams[pkt.stream_index]);
}
/* the following test is needed in case new streams appear
dynamically in stream : we ignore them */
if (pkt.stream_index >= ifile->nb_streams) {
report_new_stream(file_index, &pkt);
goto discard_packet;
}
ist = input_streams[ifile->ist_index + pkt.stream_index];
ist->data_size += pkt.size;
ist->nb_packets++;
if (ist->discard)
goto discard_packet;
if (debug_ts) {
av_log(NULL, AV_LOG_INFO, "demuxer -> ist_index:%d type:%s "
"next_dts:%s next_dts_time:%s next_pts:%s next_pts_time:%s pkt_pts:%s pkt_pts_time:%s pkt_dts:%s pkt_dts_time:%s off:%s off_time:%s\n",
ifile->ist_index + pkt.stream_index, av_get_media_type_string(ist->dec_ctx->codec_type),
av_ts2str(ist->next_dts), av_ts2timestr(ist->next_dts, &AV_TIME_BASE_Q),
av_ts2str(ist->next_pts), av_ts2timestr(ist->next_pts, &AV_TIME_BASE_Q),
av_ts2str(pkt.pts), av_ts2timestr(pkt.pts, &ist->st->time_base),
av_ts2str(pkt.dts), av_ts2timestr(pkt.dts, &ist->st->time_base),
av_ts2str(input_files[ist->file_index]->ts_offset),
av_ts2timestr(input_files[ist->file_index]->ts_offset, &AV_TIME_BASE_Q));
}
if(!ist->wrap_correction_done && is->start_time != AV_NOPTS_VALUE && ist->st->pts_wrap_bits < 64) {
int64_t stime, stime2;
// Correcting starttime based on the enabled streams
// FIXME this ideally should be done before the first use of starttime but we do not know which are the enabled streams at that point.
// so we instead do it here as part of discontinuity handling
if ( ist->next_dts == AV_NOPTS_VALUE
&& ifile->ts_offset == -is->start_time
&& (is->iformat->flags & AVFMT_TS_DISCONT)) {
int64_t new_start_time = INT64_MAX;
for (i=0; i<is->nb_streams; i++) {
AVStream *st = is->streams[i];
if(st->discard == AVDISCARD_ALL || st->start_time == AV_NOPTS_VALUE)
continue;
new_start_time = FFMIN(new_start_time, av_rescale_q(st->start_time, st->time_base, AV_TIME_BASE_Q));
}
if (new_start_time > is->start_time) {
av_log(is, AV_LOG_VERBOSE, "Correcting start time by %"PRId64"\n", new_start_time - is->start_time);
ifile->ts_offset = -new_start_time;
}
}
stime = av_rescale_q(is->start_time, AV_TIME_BASE_Q, ist->st->time_base);
stime2= stime + (1ULL<<ist->st->pts_wrap_bits);
ist->wrap_correction_done = 1;
if(stime2 > stime && pkt.dts != AV_NOPTS_VALUE && pkt.dts > stime + (1LL<<(ist->st->pts_wrap_bits-1))) {
pkt.dts -= 1ULL<<ist->st->pts_wrap_bits;
ist->wrap_correction_done = 0;
}
if(stime2 > stime && pkt.pts != AV_NOPTS_VALUE && pkt.pts > stime + (1LL<<(ist->st->pts_wrap_bits-1))) {
pkt.pts -= 1ULL<<ist->st->pts_wrap_bits;
ist->wrap_correction_done = 0;
}
}
/* add the stream-global side data to the first packet */
if (ist->nb_packets == 1)
if (ist->st->nb_side_data)
av_packet_split_side_data(&pkt);
for (i = 0; i < ist->st->nb_side_data; i++) {
AVPacketSideData *src_sd = &ist->st->side_data[i];
uint8_t *dst_data;
if (av_packet_get_side_data(&pkt, src_sd->type, NULL))
continue;
dst_data = av_packet_new_side_data(&pkt, src_sd->type, src_sd->size);
if (!dst_data)
exit_program(1);
memcpy(dst_data, src_sd->data, src_sd->size);
}
// ****<< pkt.pts: 采集时间戳(以毫秒为单位; 一般为系统时间)
// ****<< ts_offset: 起始时间戳(以毫秒为单位; 一般为第一帧采集时间戳的相反数)
// ****<< 最终.pts: 相对时间戳(以毫秒为单位; 从第一帧到现在的相对时间)
if (pkt.dts != AV_NOPTS_VALUE)
pkt.dts += av_rescale_q(ifile->ts_offset, AV_TIME_BASE_Q, ist->st->time_base);
if (pkt.pts != AV_NOPTS_VALUE)
pkt.pts += av_rescale_q(ifile->ts_offset, AV_TIME_BASE_Q, ist->st->time_base);
if (pkt.pts != AV_NOPTS_VALUE)
pkt.pts *= ist->ts_scale;
if (pkt.dts != AV_NOPTS_VALUE)
pkt.dts *= ist->ts_scale;
if (pkt.dts != AV_NOPTS_VALUE && ist->next_dts == AV_NOPTS_VALUE && !copy_ts
&& (is->iformat->flags & AVFMT_TS_DISCONT) && ifile->last_ts != AV_NOPTS_VALUE) {
int64_t pkt_dts = av_rescale_q(pkt.dts, ist->st->time_base, AV_TIME_BASE_Q);
int64_t delta = pkt_dts - ifile->last_ts;
if(delta < -1LL*dts_delta_threshold*AV_TIME_BASE ||
(delta > 1LL*dts_delta_threshold*AV_TIME_BASE &&
ist->dec_ctx->codec_type != AVMEDIA_TYPE_SUBTITLE)) {
ifile->ts_offset -= delta;
av_log(NULL, AV_LOG_DEBUG,
"Inter stream timestamp discontinuity %"PRId64", new offset= %"PRId64"\n",
delta, ifile->ts_offset);
pkt.dts -= av_rescale_q(delta, AV_TIME_BASE_Q, ist->st->time_base);
if (pkt.pts != AV_NOPTS_VALUE)
pkt.pts -= av_rescale_q(delta, AV_TIME_BASE_Q, ist->st->time_base);
}
}
if (pkt.dts != AV_NOPTS_VALUE && ist->next_dts != AV_NOPTS_VALUE &&
!copy_ts) {
int64_t pkt_dts = av_rescale_q(pkt.dts, ist->st->time_base, AV_TIME_BASE_Q);
int64_t delta = pkt_dts - ist->next_dts;
if (is->iformat->flags & AVFMT_TS_DISCONT) {
if (delta < -1LL*dts_delta_threshold*AV_TIME_BASE ||
(delta > 1LL*dts_delta_threshold*AV_TIME_BASE &&
ist->dec_ctx->codec_type != AVMEDIA_TYPE_SUBTITLE) ||
pkt_dts + AV_TIME_BASE/10 < FFMAX(ist->pts, ist->dts)) {
ifile->ts_offset -= delta;
av_log(NULL, AV_LOG_DEBUG,
"timestamp discontinuity %"PRId64", new offset= %"PRId64"\n",
delta, ifile->ts_offset);
pkt.dts -= av_rescale_q(delta, AV_TIME_BASE_Q, ist->st->time_base);
if (pkt.pts != AV_NOPTS_VALUE)
pkt.pts -= av_rescale_q(delta, AV_TIME_BASE_Q, ist->st->time_base);
}
} else {
if ( delta < -1LL*dts_error_threshold*AV_TIME_BASE ||
(delta > 1LL*dts_error_threshold*AV_TIME_BASE && ist->dec_ctx->codec_type != AVMEDIA_TYPE_SUBTITLE)) {
av_log(NULL, AV_LOG_WARNING, "DTS %"PRId64", next:%"PRId64" st:%d invalid dropping\n", pkt.dts, ist->next_dts, pkt.stream_index);
pkt.dts = AV_NOPTS_VALUE;
}
if (pkt.pts != AV_NOPTS_VALUE) {
int64_t pkt_pts = av_rescale_q(pkt.pts, ist->st->time_base, AV_TIME_BASE_Q);
delta = pkt_pts - ist->next_dts;
if ( delta < -1LL*dts_error_threshold*AV_TIME_BASE ||
(delta > 1LL*dts_error_threshold*AV_TIME_BASE && ist->dec_ctx->codec_type != AVMEDIA_TYPE_SUBTITLE)) {
av_log(NULL, AV_LOG_WARNING, "PTS %"PRId64", next:%"PRId64" invalid dropping st:%d\n", pkt.pts, ist->next_dts, pkt.stream_index);
pkt.pts = AV_NOPTS_VALUE;
}
}
}
}
if (pkt.dts != AV_NOPTS_VALUE)
ifile->last_ts = av_rescale_q(pkt.dts, ist->st->time_base, AV_TIME_BASE_Q);
if (debug_ts) {
av_log(NULL, AV_LOG_INFO, "demuxer+ffmpeg -> ist_index:%d type:%s pkt_pts:%s pkt_pts_time:%s pkt_dts:%s pkt_dts_time:%s off:%s off_time:%s\n",
ifile->ist_index + pkt.stream_index, av_get_media_type_string(ist->dec_ctx->codec_type),
av_ts2str(pkt.pts), av_ts2timestr(pkt.pts, &ist->st->time_base),
av_ts2str(pkt.dts), av_ts2timestr(pkt.dts, &ist->st->time_base),
av_ts2str(input_files[ist->file_index]->ts_offset),
av_ts2timestr(input_files[ist->file_index]->ts_offset, &AV_TIME_BASE_Q));
}
sub2video_heartbeat(ist, pkt.pts);
ret = output_packet(ist, &pkt); // ****<< see output_packet.c
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "Error while decoding stream #%d:%d: %s\n",
ist->file_index, ist->st->index, av_err2str(ret));
if (exit_on_error)
exit_program(1);
}
discard_packet:
av_free_packet(&pkt);
return 0;
}