[FFmpeg-devel] [PATCH] Fix segment muxer

[Vasily]

Anything else I have to do to make this patch eventually taken in?

Thanks,
Vasily

пн, 7 окт. 2019 г. в 15:54, <just.one.man at yandex.ru>:

> 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..8b985df 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 = AV_NOPTS_VALUE;
>          /* 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 != AV_NOPTS_VALUE) {
> +                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
>
> Now I tried to re-format as Nicolas George said, hopefully this is okay
> and won't make a third entry in patchwork (if it does - how do I stop it
> from doing so?)
>
> 07.10.2019, 15:15, "Nicolas George" <george at nsup.org>:
> > just.one.man at yandex.ru (12019-10-07):
> >>  Updated patch
> >
> > This should be after the triple dash, because it does not belong in the
> > commit message.
> >
> >>  ---
> >>
> >>  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
> >>  ---
> >
> > This should be before the triple dash, because it does belong in the
> > commit message.
> >
> > I did not look at the code.
> >
> > Regards,
> >
> > --
> >   Nicolas George
> > ,
> >
> > _______________________________________________
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> >
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