[FFmpeg-devel] [PATCH] Blackframe video filter now sets frame metadata accordingly.

[wm4]

On Fri, 11 Jul 2014 22:13:54 +0200
Stepan Bujnak <stepan.bujnak at gmail.com> wrote:

> the libavfilter/vf_blackframe.c filter now not only logs detected
> values, but also sets frame metadata. The metadata have prefix
> 'lavfi.blackframe.*'.
> 
> Signed-off-by: Stepan Bujnak <stepan.bujnak at gmail.com>
> ---
>  libavfilter/vf_blackframe.c | 29 +++++++++++++++++++++++++----
>  1 file changed, 25 insertions(+), 4 deletions(-)
> 
> diff --git a/libavfilter/vf_blackframe.c b/libavfilter/vf_blackframe.c
> index 0eeda61..d89a25e 100644
> --- a/libavfilter/vf_blackframe.c
> +++ b/libavfilter/vf_blackframe.c
> @@ -58,6 +58,10 @@ static int query_formats(AVFilterContext *ctx)
>      return 0;
>  }
>  
> +#define SET_META(key, format, value) \
> +    snprintf(buf, sizeof(buf), format, value);  \
> +    av_dict_set(metadata, key, buf, 0)
> +
>  static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
>  {
>      AVFilterContext *ctx = inlink->dst;
> @@ -65,6 +69,10 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
>      int x, i;
>      int pblack = 0;
>      uint8_t *p = frame->data[0];
> +    AVDictionary **metadata;
> +    double t = -1;
> +    char type;
> +    char buf[32];
>  
>      for (i = 0; i < frame->height; i++) {
>          for (x = 0; x < inlink->w; x++)
> @@ -76,12 +84,25 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
>          s->last_keyframe = s->frame;
>  
>      pblack = s->nblack * 100 / (inlink->w * inlink->h);
> -    if (pblack >= s->bamount)
> +    if (pblack >= s->bamount) {
> +        metadata = avpriv_frame_get_metadatap(frame);
> +        type = av_get_picture_type_char(frame->pict_type);
> +
> +        if (frame->pts != AV_NOPTS_VALUE) {
> +            t = frame->pts * av_q2d(inlink->time_base);
> +        }
> +
>          av_log(ctx, AV_LOG_INFO, "frame:%u pblack:%u pts:%"PRId64" t:%f "
>                 "type:%c last_keyframe:%d\n",
> -               s->frame, pblack, frame->pts,
> -               frame->pts == AV_NOPTS_VALUE ? -1 : frame->pts * av_q2d(inlink->time_base),
> -               av_get_picture_type_char(frame->pict_type), s->last_keyframe);
> +               s->frame, pblack, frame->pts, t, type, s->last_keyframe);
> +
> +        SET_META("lavfi.blackframe.frame", "%u", s->frame);
> +        SET_META("lavfi.blackframe.pblack", "%u", pblack);
> +        SET_META("lavfi.blackframe.pts", "%"PRId64, frame->pts);

It shouldn't be needed to set the PTS - the frame already has it.

> +        SET_META("lavfi.blackframe.t", "%f", t);
> +        SET_META("lavfi.blackframe.type", "%c", type);
> +        SET_META("lavfi.blackframe.last_keyframe", "%d", s->last_keyframe);
> +    }
>  
>      s->frame++;
>      s->nblack = 0;