int av_read_frame(AVFormatContext *s, AVPacket *pkt) { const int genpts = s->flags & AVFMT_FLAG_GENPTS; int eof = 0; int ret; AVStream *st; if (!genpts) { ret = s->packet_buffer ? read_from_packet_buffer(&s->packet_buffer, &s->packet_buffer_end, pkt) : read_frame_internal(s, pkt); if (ret < 0) return ret; goto return_packet; } for (;;) { AVPacketList *pktl = s->packet_buffer; if (pktl) { AVPacket *next_pkt = &pktl->pkt; if (next_pkt->dts != AV_NOPTS_VALUE) { int wrap_bits = s->streams[next_pkt->stream_index]->pts_wrap_bits; // last dts seen for this stream. if any of packets following // current one had no dts, we will set this to AV_NOPTS_VALUE. int64_t last_dts = next_pkt->dts; while (pktl && next_pkt->pts == AV_NOPTS_VALUE) { if (pktl->pkt.stream_index == next_pkt->stream_index && (av_compare_mod(next_pkt->dts, pktl->pkt.dts, 2LL << (wrap_bits - 1)) < 0)) { if (av_compare_mod(pktl->pkt.pts, pktl->pkt.dts, 2LL << (wrap_bits - 1))) { //not b frame next_pkt->pts = pktl->pkt.dts; } if (last_dts != AV_NOPTS_VALUE) { // Once last dts was set to AV_NOPTS_VALUE, we don't change it. last_dts = pktl->pkt.dts; } } pktl = pktl->next; } if (eof && next_pkt->pts == AV_NOPTS_VALUE && last_dts != AV_NOPTS_VALUE) { // Fixing the last reference frame had none pts issue (For MXF etc). // We only do this when // 1. eof. // 2. we are not able to resolve a pts value for current packet. // 3. the packets for this stream at the end of the files had valid dts. next_pkt->pts = last_dts + next_pkt->duration; } pktl = s->packet_buffer; } /* read packet from packet buffer, if there is data */ if (!(next_pkt->pts == AV_NOPTS_VALUE && next_pkt->dts != AV_NOPTS_VALUE && !eof)) { ret = read_from_packet_buffer(&s->packet_buffer, &s->packet_buffer_end, pkt); goto return_packet; } } ret = read_frame_internal(s, pkt); if (ret < 0) { if (pktl && ret != AVERROR(EAGAIN)) { eof = 1; continue; } else return ret; } if (av_dup_packet(add_to_pktbuf(&s->packet_buffer, pkt, &s->packet_buffer_end)) < 0) return AVERROR(ENOMEM); } return_packet: st = s->streams[pkt->stream_index]; if (st->skip_samples) { uint8_t *p = av_packet_new_side_data(pkt, AV_PKT_DATA_SKIP_SAMPLES, 10); AV_WL32(p, st->skip_samples); av_log(s, AV_LOG_DEBUG, "demuxer injecting skip %d\n", st->skip_samples); st->skip_samples = 0; } if ((s->iformat->flags & AVFMT_GENERIC_INDEX) && pkt->flags & AV_PKT_FLAG_KEY) { ff_reduce_index(s, st->index); av_add_index_entry(st, pkt->pos, pkt->dts, 0, 0, AVINDEX_KEYFRAME); } if (is_relative(pkt->dts)) pkt->dts -= RELATIVE_TS_BASE; if (is_relative(pkt->pts)) pkt->pts -= RELATIVE_TS_BASE; return ret; }