[FFmpeg-devel] [PATCH] avformat/matroskaenc: Fix writing of markers

[Martin Storsjö]

On Mon, 28 Aug 2023, Steinar H. Gunderson wrote:

> When the marker writing code was merged from libav to FFmpeg
> in dc62016c, it failed to take into account that the meaning of
> cluster_pos had changed in bda5b662; in particular, the special
> value for “I'm not currently working on a cluster” had changed
> from 0 to -1. This makes the avio_write_marker() call never
> be called. Update the if statement to fix it.
>
> Fixes: Ticket9843
> Signed-off-by: Steinar H. Gunderson <steinar+ffmpeg at gunderson.no>
> ---
> libavformat/matroskaenc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
> index e813ef86cf7..1dfcf763e2d 100644
> --- a/libavformat/matroskaenc.c
> +++ b/libavformat/matroskaenc.c
> @@ -3027,7 +3027,7 @@ static int mkv_write_packet(AVFormatContext *s, const AVPacket *pkt)
>         }
>     }
> 
> -    if (!mkv->cluster_pos)
> +    if (mkv->cluster_pos == -1)
>         avio_write_marker(s->pb,
>                           av_rescale_q(pkt->dts, s->streams[pkt->stream_index]->time_base, AV_TIME_BASE_Q),
>                           keyframe && (mkv->have_video ? codec_type == AVMEDIA_TYPE_VIDEO : 1) ? AVIO_DATA_MARKER_SYNC_POINT : AVIO_DATA_MARKER_BOUNDARY_POINT);
> -- 
> 2.39.2

LGTM, thanks, this sounds reasonable to me.

I'll push it tomorrow or so.

// Martin