[FFmpeg-devel] [PATCH] lavf/mxfdec: fix seeking before the first keyframe

[Tomas Härdin]

On Sat, 2015-11-28 at 02:56 +0100, Marton Balint wrote:
> Regression since 53f2ef2c4afb1d49a679dea9163cb0e4671f3117.
> Fixes ticket #5017.
> 
> Signed-off-by: Marton Balint <cus at passwd.hu>
> ---
>  libavformat/mxfdec.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
> index 429f46a..926d2a3 100644
> --- a/libavformat/mxfdec.c
> +++ b/libavformat/mxfdec.c
> @@ -3181,6 +3181,16 @@ static int mxf_read_seek(AVFormatContext *s, int stream_index, int64_t sample_ti
>          sample_time = FFMAX(sample_time, 0);
>  
>          if (t->fake_index) {
> +            /* The first frames may not be keyframes in presentation order, so
> +             * we have to advance the target to be able to find the first
> +             * keyframe backwards... */
> +            if (!(flags & AVSEEK_FLAG_ANY) &&
> +                (flags & AVSEEK_FLAG_BACKWARD) &&
> +                t->ptses[0] != AV_NOPTS_VALUE &&

Can the size of t->ptses ever be zero here?


> +                sample_time < t->ptses[0] &&
> +                (t->fake_index[t->ptses[0]].flags & AVINDEX_KEYFRAME))

Do t->ptses always point inside t->fake_index?

> +                sample_time = t->ptses[0];
> +

Should be OK otherwise, since it only affects seeking and fixes a
regression. Ideally we should be doing something better for seeking, I
think..

/Tomas
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