[FFmpeg-devel] [PATCH 1/2] avfilter/vf_palettegen: add mode for generating palette for each input frame

[Clément Bœsch]

On Fri, Sep 02, 2016 at 10:42:09PM +0200, Paul B Mahol wrote:
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
>  libavfilter/vf_palettegen.c | 27 +++++++++++++++++++++++----
>  1 file changed, 23 insertions(+), 4 deletions(-)
> 
> diff --git a/libavfilter/vf_palettegen.c b/libavfilter/vf_palettegen.c
> index fccc5ca..3018b06 100644
> --- a/libavfilter/vf_palettegen.c
> +++ b/libavfilter/vf_palettegen.c
> @@ -53,6 +53,7 @@ struct hist_node {
>  enum {
>      STATS_MODE_ALL_FRAMES,
>      STATS_MODE_DIFF_FRAMES,
> +    STATS_MODE_SINGLE_FRAMES,
>      NB_STATS_MODE
>  };
>  
> @@ -80,9 +81,10 @@ typedef struct {
>  static const AVOption palettegen_options[] = {
>      { "max_colors", "set the maximum number of colors to use in the palette", OFFSET(max_colors), AV_OPT_TYPE_INT, {.i64=256}, 4, 256, FLAGS },
>      { "reserve_transparent", "reserve a palette entry for transparency", OFFSET(reserve_transparent), AV_OPT_TYPE_BOOL, {.i64=1}, 0, 1, FLAGS },
> -    { "stats_mode", "set statistics mode", OFFSET(stats_mode), AV_OPT_TYPE_INT, {.i64=STATS_MODE_ALL_FRAMES}, 0, NB_STATS_MODE, FLAGS, "mode" },
> +    { "stats_mode", "set statistics mode", OFFSET(stats_mode), AV_OPT_TYPE_INT, {.i64=STATS_MODE_ALL_FRAMES}, 0, NB_STATS_MODE-1, FLAGS, "mode" },
>          { "full", "compute full frame histograms", 0, AV_OPT_TYPE_CONST, {.i64=STATS_MODE_ALL_FRAMES}, INT_MIN, INT_MAX, FLAGS, "mode" },
>          { "diff", "compute histograms only for the part that differs from previous frame", 0, AV_OPT_TYPE_CONST, {.i64=STATS_MODE_DIFF_FRAMES}, INT_MIN, INT_MAX, FLAGS, "mode" },
> +        { "single", "compute new histogram for each frame", 0, AV_OPT_TYPE_CONST, {.i64=STATS_MODE_SINGLE_FRAMES}, INT_MIN, INT_MAX, FLAGS, "mode" },
>      { NULL }
>  };
>  
> @@ -480,8 +482,9 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
>  {
>      AVFilterContext *ctx = inlink->dst;
>      PaletteGenContext *s = ctx->priv;
> -    const int ret = s->prev_frame ? update_histogram_diff(s->histogram, s->prev_frame, in)
> -                                  : update_histogram_frame(s->histogram, in);
> +    int ret = s->prev_frame ? update_histogram_diff(s->histogram, s->prev_frame, in)
> +                            : update_histogram_frame(s->histogram, in);
> +    int64_t in_pts = in->pts;
>  
>      if (ret > 0)
>          s->nb_refs += ret;
> @@ -493,6 +496,22 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
>          av_frame_free(&in);
>      }
>  
> +    if (s->stats_mode == STATS_MODE_SINGLE_FRAMES) {
> +        AVFrame *out;
> +        int i;
> +
> +        out = get_palette_frame(ctx);
> +        out->pts = in_pts;
> +        ret = ff_filter_frame(ctx->outputs[0], out);
> +        for (i = 0; i < HIST_SIZE; i++)
> +            av_freep(&s->histogram[i].entries);
> +        av_freep(&s->refs);
> +        s->nb_refs = 0;
> +        s->nb_boxes = 0;
> +        memset(s->boxes, 0, sizeof(s->boxes));
> +        memset(s->histogram, 0, sizeof(s->histogram));
> +    }
> +


I'd prefer:

    if (s->stats_mode == STATS_MODE_DIFF_FRAMES) {
        av_frame_free(&s->prev_frame);
        s->prev_frame = in;
    if (s->stats_mode == STATS_MODE_SINGLE_FRAMES) {

        // ...
        out->pts = in->pts;
        // ...
        av_frame_free(&in);

    } else {
        av_frame_free(&in);
    }

[...]

otherwise LGTM, thanks

-- 
Clément B.