| Message ID | 14058761570101997@sas2-5edf99ef3846.qloud-c.yandex.net |
|---|---|
| State | Superseded |
| Headers | show |
On Thu, 3 Oct 2019, just.one.man@yandex.ru wrote: > It seems that my first attempt to send the patch failed (probably because my box where I executed "git send-email" failed reverse smtp check), so I'm going to re-send it to this same thread. > > --- > > When incoming media has non-zero start PTS, > segment muxer would fail to correctly calculate > the point where to chunk segments, as it always > assumed that media starts with PTS==0. > > This change removes this assumption by remembering > the PTS of the very first frame passed through the muxer. > > Also fix starting points of first segment > --- > libavformat/segment.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/libavformat/segment.c b/libavformat/segment.c > index e308206..2478d8f 100644 > --- a/libavformat/segment.c > +++ b/libavformat/segment.c > @@ -87,6 +87,7 @@ typedef struct SegmentContext { > int64_t last_val; ///< remember last time for wrap around detection > int cut_pending; > int header_written; ///< whether we've already called avformat_write_header > + int64_t start_pts; ///< pts of the very first packet processed, used to compute correct segment length > > char *entry_prefix; ///< prefix to add to list entry filenames > int list_type; ///< set the list type > @@ -702,6 +703,7 @@ static int seg_init(AVFormatContext *s) > if ((ret = parse_frames(s, &seg->frames, &seg->nb_frames, seg->frames_str)) < 0) > return ret; > } else { > + seg->start_pts = -1; AV_NOPTS_VALUE would be probably better for this purpose, even if the muxer won't get negative timestamps unless allowed by the AVFMT_TS_NEGATIVE flag. Regards, Marton > /* set default value if not specified */ > if (!seg->time_str) > seg->time_str = av_strdup("2"); > @@ -914,7 +916,15 @@ calc_times: > seg->cut_pending = 1; > seg->last_val = wrapped_val; > } else { > - end_pts = seg->time * (seg->segment_count + 1); > + if (seg->start_pts != -1) { > + end_pts = seg->start_pts + seg->time * (seg->segment_count + 1); > + } else if (pkt->stream_index == seg->reference_stream_index && pkt->pts != AV_NOPTS_VALUE) { > + // this is the first packet of the reference stream we see, initialize start point > + seg->start_pts = av_rescale_q(pkt->pts, st->time_base, AV_TIME_BASE_Q); > + seg->cur_entry.start_time = (double)pkt->pts * av_q2d(st->time_base); > + seg->cur_entry.start_pts = seg->start_pts; > + end_pts = seg->start_pts + seg->time * (seg->segment_count + 1); > + } > } > } > > -- > 1.7.9.5 > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
I used that value somewhere during patch development, but I eventually settled on -1, because that "start_pts" and "end_pts" are using some other units, not the unit used by pkt->pts. So I wanted to make a distinction. Though a possibility of negative timestamps didn't come to me, so I probably have to change it back to AV_NOPTS_VALUE. P.S. Thanks for reviewing my patch! вс, 6 окт. 2019 г., 13:56 Marton Balint <cus@passwd.hu>: > > > On Thu, 3 Oct 2019, just.one.man@yandex.ru wrote: > > > It seems that my first attempt to send the patch failed (probably > because my box where I executed "git send-email" failed reverse smtp > check), so I'm going to re-send it to this same thread. > > > > --- > > > > When incoming media has non-zero start PTS, > > segment muxer would fail to correctly calculate > > the point where to chunk segments, as it always > > assumed that media starts with PTS==0. > > > > This change removes this assumption by remembering > > the PTS of the very first frame passed through the muxer. > > > > Also fix starting points of first segment > > --- > > libavformat/segment.c | 12 +++++++++++- > > 1 file changed, 11 insertions(+), 1 deletion(-) > > > > diff --git a/libavformat/segment.c b/libavformat/segment.c > > index e308206..2478d8f 100644 > > --- a/libavformat/segment.c > > +++ b/libavformat/segment.c > > @@ -87,6 +87,7 @@ typedef struct SegmentContext { > > int64_t last_val; ///< remember last time for wrap around > detection > > int cut_pending; > > int header_written; ///< whether we've already called > avformat_write_header > > + int64_t start_pts; ///< pts of the very first packet processed, > used to compute correct segment length > > > > char *entry_prefix; ///< prefix to add to list entry filenames > > int list_type; ///< set the list type > > @@ -702,6 +703,7 @@ static int seg_init(AVFormatContext *s) > > if ((ret = parse_frames(s, &seg->frames, &seg->nb_frames, > seg->frames_str)) < 0) > > return ret; > > } else { > > + seg->start_pts = -1; > > AV_NOPTS_VALUE would be probably better for this purpose, even if the > muxer won't get negative timestamps unless allowed by the > AVFMT_TS_NEGATIVE flag. > > Regards, > Marton > > > /* set default value if not specified */ > > if (!seg->time_str) > > seg->time_str = av_strdup("2"); > > @@ -914,7 +916,15 @@ calc_times: > > seg->cut_pending = 1; > > seg->last_val = wrapped_val; > > } else { > > - end_pts = seg->time * (seg->segment_count + 1); > > + if (seg->start_pts != -1) { > > + end_pts = seg->start_pts + seg->time * > (seg->segment_count + 1); > > + } else if (pkt->stream_index == seg->reference_stream_index > && pkt->pts != AV_NOPTS_VALUE) { > > + // this is the first packet of the reference stream we > see, initialize start point > > + seg->start_pts = av_rescale_q(pkt->pts, st->time_base, > AV_TIME_BASE_Q); > > + seg->cur_entry.start_time = (double)pkt->pts * > av_q2d(st->time_base); > > + seg->cur_entry.start_pts = seg->start_pts; > > + end_pts = seg->start_pts + seg->time * > (seg->segment_count + 1); > > + } > > } > > } > > > > -- > > 1.7.9.5 > > _______________________________________________ > > ffmpeg-devel mailing list > > ffmpeg-devel@ffmpeg.org > > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > > > To unsubscribe, visit link above, or email > > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe". > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
diff --git a/libavformat/segment.c b/libavformat/segment.c index e308206..2478d8f 100644 --- a/libavformat/segment.c +++ b/libavformat/segment.c @@ -87,6 +87,7 @@ typedef struct SegmentContext { int64_t last_val; ///< remember last time for wrap around detection int cut_pending; int header_written; ///< whether we've already called avformat_write_header + int64_t start_pts; ///< pts of the very first packet processed, used to compute correct segment length char *entry_prefix; ///< prefix to add to list entry filenames int list_type; ///< set the list type @@ -702,6 +703,7 @@ static int seg_init(AVFormatContext *s) if ((ret = parse_frames(s, &seg->frames, &seg->nb_frames, seg->frames_str)) < 0) return ret; } else { + seg->start_pts = -1; /* set default value if not specified */ if (!seg->time_str) seg->time_str = av_strdup("2"); @@ -914,7 +916,15 @@ calc_times: seg->cut_pending = 1; seg->last_val = wrapped_val; } else { - end_pts = seg->time * (seg->segment_count + 1); + if (seg->start_pts != -1) { + end_pts = seg->start_pts + seg->time * (seg->segment_count + 1); + } else if (pkt->stream_index == seg->reference_stream_index && pkt->pts != AV_NOPTS_VALUE) { + // this is the first packet of the reference stream we see, initialize start point + seg->start_pts = av_rescale_q(pkt->pts, st->time_base, AV_TIME_BASE_Q); + seg->cur_entry.start_time = (double)pkt->pts * av_q2d(st->time_base); + seg->cur_entry.start_pts = seg->start_pts; + end_pts = seg->start_pts + seg->time * (seg->segment_count + 1); + } } }