[FFmpeg-devel] [PATCH] libavformat/mov: Fix inserting frames before current_frame.

[Jacob Trimble]

Ping

On Thu, Jul 27, 2017 at 10:34 AM, Jacob Trimble <modmaker at google.com> wrote:
> When using streaming input, it may be possible to see frames that appear
> before the current_frame.  When these frames are inserted into the
> index, the current_frame needs to be updated so it is still pointing
> at the same frame.
>
> Signed-off-by: Jacob Trimble <modmaker at google.com>
> ---
>  libavformat/mov.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index 63f84be782..d039f27063 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -4259,7 +4259,7 @@ static int mov_read_trun(MOVContext *c, AVIOContext *pb, MOVAtom atom)
>      int64_t dts;
>      int data_offset = 0;
>      unsigned entries, first_sample_flags = frag->flags;
> -    int flags, distance, i, err;
> +    int flags, distance, i, err, old_nb_index_entries;
>
>      for (i = 0; i < c->fc->nb_streams; i++) {
>          if (c->fc->streams[i]->id == frag->track_id) {
> @@ -4352,13 +4352,19 @@ static int mov_read_trun(MOVContext *c, AVIOContext *pb, MOVAtom atom)
>                                    MOV_FRAG_SAMPLE_FLAG_DEPENDS_YES));
>          if (keyframe)
>              distance = 0;
> +        old_nb_index_entries = st->nb_index_entries;
>          err = av_add_index_entry(st, offset, dts, sample_size, distance,
>                                   keyframe ? AVINDEX_KEYFRAME : 0);
>          if (err < 0) {
>              av_log(c->fc, AV_LOG_ERROR, "Failed to add index entry\n");
> +        } else if (err <= sc->current_sample && err + 1 != st->nb_index_entries &&
> +            st->nb_index_entries != old_nb_index_entries) {
> +            // if we inserted a new item before the current sample, move the
> +            // counter ahead so it is still pointing to the same sample.
> +            sc->current_sample++;
>          }
> -        av_log(c->fc, AV_LOG_TRACE, "AVIndex stream %d, sample %u, offset %"PRIx64", dts %"PRId64", "
> -                "size %u, distance %d, keyframe %d\n", st->index, sc->sample_count+i,
> +        av_log(c->fc, AV_LOG_TRACE, "AVIndex stream %d, sample %d, offset %"PRIx64", dts %"PRId64", "
> +                "size %u, distance %d, keyframe %d\n", st->index, err,
>                  offset, dts, sample_size, distance, keyframe);
>          distance++;
>          dts += sample_duration;