[FFmpeg-devel] [PATCH] lavf: consider codec framerate for framerate detection

[wm4]

On Wed, 31 May 2017 18:26:01 +0200
wm4 <nfxjfg at googlemail.com> wrote:

> Fixes detection of some TV sample as 24.5 FPS. With the patch applied,
> it's detected as 25 FPS.
> 
> This is enabled for mpegts only.
> ---
>  libavformat/internal.h |  5 +++++
>  libavformat/mpegts.c   |  2 ++
>  libavformat/utils.c    | 10 ++++++++++
>  3 files changed, 17 insertions(+)
> 
> diff --git a/libavformat/internal.h b/libavformat/internal.h
> index c856945ce9..d136c79bdd 100644
> --- a/libavformat/internal.h
> +++ b/libavformat/internal.h
> @@ -145,6 +145,11 @@ struct AVFormatInternal {
>       * ID3v2 tag useful for MP3 demuxing
>       */
>      AVDictionary *id3v2_meta;
> +
> +    /*
> +     * Prefer the codec framerate for avg_frame_rate computation.
> +     */
> +    int prefer_codec_framerate;
>  };
>  
>  struct AVStreamInternal {
> diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
> index 3eff1522bd..4d2f5c6802 100644
> --- a/libavformat/mpegts.c
> +++ b/libavformat/mpegts.c
> @@ -2616,6 +2616,8 @@ static int mpegts_read_header(AVFormatContext *s)
>      int len;
>      int64_t pos, probesize = s->probesize;
>  
> +    s->internal->prefer_codec_framerate = 1;
> +
>      if (ffio_ensure_seekback(pb, probesize) < 0)
>          av_log(s, AV_LOG_WARNING, "Failed to allocate buffers for seekback\n");
>  
> diff --git a/libavformat/utils.c b/libavformat/utils.c
> index fbd8b58ac2..b50ca2f7ac 100644
> --- a/libavformat/utils.c
> +++ b/libavformat/utils.c
> @@ -3903,6 +3903,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
>                  st->info->codec_info_duration) {
>                  int best_fps      = 0;
>                  double best_error = 0.01;
> +                AVRational codec_frame_rate = avctx->framerate;
>  
>                  if (st->info->codec_info_duration        >= INT64_MAX / st->time_base.num / 2||
>                      st->info->codec_info_duration_fields >= INT64_MAX / st->time_base.den ||
> @@ -3923,6 +3924,15 @@ FF_ENABLE_DEPRECATION_WARNINGS
>                          best_error = error;
>                          best_fps   = std_fps.num;
>                      }
> +
> +                    if (ic->internal->prefer_codec_framerate && codec_frame_rate.num > 0 && codec_frame_rate.den > 0) {
> +                        error       = fabs(av_q2d(codec_frame_rate) /
> +                                           av_q2d(std_fps) - 1);
> +                        if (error < best_error) {
> +                            best_error = error;
> +                            best_fps   = std_fps.num;
> +                        }
> +                    }
>                  }
>                  if (best_fps)
>                      av_reduce(&st->avg_frame_rate.num, &st->avg_frame_rate.den,

Pushed.