[FFmpeg-devel] [PATCH 3/3] ffmpeg: ensure that -fix_sub_duration doesnt create subtitles with zero duration

[Nicolas George]

Le tridi 3 frimaire, an CCXXII, Marton Balint a écrit :
> Signed-off-by: Marton Balint <cus at passwd.hu>
> ---
>  ffmpeg.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/ffmpeg.c b/ffmpeg.c
> index 5ba9450..4bb88e6 100644
> --- a/ffmpeg.c
> +++ b/ffmpeg.c
> @@ -1801,19 +1801,23 @@ static int transcode_subtitles(InputStream *ist, AVPacket *pkt, int *got_output)
>      }
>  
>      if (ist->fix_sub_duration) {
> +        int end = 1;
>          if (ist->prev_sub.got_output) {
> -            int end = av_rescale(subtitle.pts - ist->prev_sub.subtitle.pts,
> -                                 1000, AV_TIME_BASE);
> +            end = av_rescale(subtitle.pts - ist->prev_sub.subtitle.pts,
> +                             1000, AV_TIME_BASE);
>              if (end < ist->prev_sub.subtitle.end_display_time) {
>                  av_log(ist->st->codec, AV_LOG_DEBUG,
> -                       "Subtitle duration reduced from %d to %d\n",
> -                       ist->prev_sub.subtitle.end_display_time, end);
> +                       "Subtitle duration reduced from %d to %d%s\n",
> +                       ist->prev_sub.subtitle.end_display_time, end,
> +                       end <= 0 ? ", dropping it" : "");
>                  ist->prev_sub.subtitle.end_display_time = end;
>              }
>          }
>          FFSWAP(int,        *got_output, ist->prev_sub.got_output);
>          FFSWAP(int,        ret,         ist->prev_sub.ret);
>          FFSWAP(AVSubtitle, subtitle,    ist->prev_sub.subtitle);
> +        if (end <= 0)
> +            goto out;
>      }
>  
>      if (!*got_output)

This would treat differently subtitles with 0 duration depending on whether
it comes from -fix_sub_duration or was there from the start. It it on
purpose?

Can you explain (or point to the mail where you already did, if so) where
you are going with that? The encode-decode API of subtitles is a mess, but
we will not manage to fix it unless we at least agree on how it should be.

Regards,

-- 
  Nicolas George
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