[FFmpeg-devel] [PATCH] avformat/matroskaenc: Sort cues entries by pts

[Andreas Rheinhardt]

Andreas Rheinhardt:
> Currently they are ordered as-written (i.e. by increasing position);
> in case av_interleaved_write_frame() is used, this is (mostly)
> the same as ordered by increasing dts.
> Yet the Matroska specification strongly recommends (SHOULD) that
> the CuePoints be sorted by CueTime. mkvalidator warns when they are
> not. Therefore this commit sorts them accordingly.
> 
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
> ---
>  libavformat/matroskaenc.c | 19 ++++++++++++++-----
>  1 file changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
> index f08ead0a96..8c4cf4024a 100644
> --- a/libavformat/matroskaenc.c
> +++ b/libavformat/matroskaenc.c
> @@ -533,6 +533,7 @@ static int mkv_add_cuepoint(MatroskaMuxContext *mkv, int stream, int64_t ts,
>  {
>      mkv_cues *cues = &mkv->cues;
>      mkv_cuepoint *entries = cues->entries;
> +    unsigned idx = cues->num_entries;
>  
>      if (ts < 0)
>          return 0;
> @@ -542,11 +543,19 @@ static int mkv_add_cuepoint(MatroskaMuxContext *mkv, int stream, int64_t ts,
>          return AVERROR(ENOMEM);
>      cues->entries = entries;
>  
> -    cues->entries[cues->num_entries].pts           = ts;
> -    cues->entries[cues->num_entries].stream_idx    = stream;
> -    cues->entries[cues->num_entries].cluster_pos   = cluster_pos - mkv->segment_offset;
> -    cues->entries[cues->num_entries].relative_pos  = relative_pos;
> -    cues->entries[cues->num_entries++].duration    = duration;
> +    /* Make sure the cues entries are sorted by pts. */
> +    while (idx > 0 && entries[idx - 1].pts > ts)
> +        idx--;
> +    memmove(&entries[idx + 1], &entries[idx],
> +            (cues->num_entries - idx) * sizeof(entries[0]));
> +
> +    entries[idx].pts           = ts;
> +    entries[idx].stream_idx    = stream;
> +    entries[idx].cluster_pos   = cluster_pos - mkv->segment_offset;
> +    entries[idx].relative_pos  = relative_pos;
> +    entries[idx].duration      = duration;
> +
> +    cues->num_entries++;
>  
>      return 0;
>  }
> 
Will apply tonight unless there are objections.

- Andreas