[FFmpeg-devel] [PATCH 6/7] avfilter/vf_framerate: do not calculate scene change score multiple times for the same frame

Marton Balint cus at passwd.hu
Sat Dec 16 13:26:29 EET 2017



On Sun, 10 Dec 2017, Marton Balint wrote:

> This speeds up the filter, and also fixes scene change detection score which is
> reduced based on the difference of the current MAFD to the preivous MAFD.
> Obviously if we compare two frames twice, the difference will be 0...

Paul, you missed this one by mistake, or do you need more time to review?

Thanks,
Marton


>
> Signed-off-by: Marton Balint <cus at passwd.hu>
> ---
> libavfilter/vf_framerate.c | 45 +++++++++++++++++++++++++++------------------
> 1 file changed, 27 insertions(+), 18 deletions(-)
>
> diff --git a/libavfilter/vf_framerate.c b/libavfilter/vf_framerate.c
> index dd106f8e5b..5fffc2a172 100644
> --- a/libavfilter/vf_framerate.c
> +++ b/libavfilter/vf_framerate.c
> @@ -71,6 +71,7 @@ typedef struct FrameRateContext {
>
>     AVFrame *srce[N_SRCE];              ///< buffered source frames
>     int64_t srce_pts_dest[N_SRCE];      ///< pts for source frames scaled to output timebase
> +    double scre_score[N_SRCE];          ///< scene change score compared to the next scre frame
>     int64_t pts;                        ///< pts of frame we are working on
>
>     int max;
> @@ -113,9 +114,11 @@ static void next_source(AVFilterContext *ctx)
>     for (i = s->last; i > s->frst; i--) {
>         ff_dlog(ctx, "next_source() copy %d to %d\n", i - 1, i);
>         s->srce[i] = s->srce[i - 1];
> +        s->scre_score[i] = s->scre_score[i - 1];
>     }
>     ff_dlog(ctx, "next_source() make %d null\n", s->frst);
>     s->srce[s->frst] = NULL;
> +    s->scre_score[s->frst] = -1.0;
> }
> 
> static av_always_inline int64_t sad_8x8_16(const uint16_t *src1, ptrdiff_t stride1,
> @@ -171,8 +174,7 @@ static double get_scene_score(AVFilterContext *ctx, AVFrame *crnt, AVFrame *next
>
>     ff_dlog(ctx, "get_scene_score()\n");
> 
> -    if (crnt &&
> -        crnt->height == next->height &&
> +    if (crnt->height == next->height &&
>         crnt->width  == next->width) {
>         int64_t sad;
>         double mafd, diff;
> @@ -304,21 +306,26 @@ static int filter_slice16(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
> }
> 
> static int blend_frames(AVFilterContext *ctx, float interpolate,
> -                        AVFrame *copy_src1, AVFrame *copy_src2)
> +                        int src1, int src2)
> {
>     FrameRateContext *s = ctx->priv;
>     AVFilterLink *outlink = ctx->outputs[0];
>     double interpolate_scene_score = 0;
> 
> -    if ((s->flags & FRAMERATE_FLAG_SCD) && copy_src2) {
> -        interpolate_scene_score = get_scene_score(ctx, copy_src1, copy_src2);
> +    if ((s->flags & FRAMERATE_FLAG_SCD) && s->srce[src1] && s->srce[src2]) {
> +        int i1 = src1 < src2 ? src1 : src2;
> +        int i2 = src1 < src2 ? src2 : src1;
> +        if (i2 == i1 + 1 && s->scre_score[i1] >= 0.0)
> +            interpolate_scene_score = s->scre_score[i1];
> +        else
> +            interpolate_scene_score = s->scre_score[i1] = get_scene_score(ctx, s->srce[i1], s->srce[i2]);
>         ff_dlog(ctx, "blend_frames() interpolate scene score:%f\n", interpolate_scene_score);
>     }
>     // decide if the shot-change detection allows us to blend two frames
> -    if (interpolate_scene_score < s->scene_score && copy_src2) {
> +    if (interpolate_scene_score < s->scene_score && s->srce[src2]) {
>         ThreadData td;
> -        td.copy_src1 = copy_src1;
> -        td.copy_src2 = copy_src2;
> +        td.copy_src1 = s->srce[src1];
> +        td.copy_src2 = s->srce[src2];
>         td.src2_factor = fabsf(interpolate) * (1 << (s->bitdepth - 8));
>         td.src1_factor = s->max - td.src2_factor;
> 
> @@ -340,8 +347,8 @@ static int process_work_frame(AVFilterContext *ctx, int stop)
> {
>     FrameRateContext *s = ctx->priv;
>     int64_t work_next_pts;
> -    AVFrame *copy_src1;
>     float interpolate;
> +    int src1, src2;
>
>     ff_dlog(ctx, "process_work_frame()\n");
> 
> @@ -385,28 +392,26 @@ static int process_work_frame(AVFilterContext *ctx, int stop)
>     // calculate interpolation
>     interpolate = ((s->pts - s->srce_pts_dest[s->crnt]) * 256.0 / s->average_srce_pts_dest_delta);
>     ff_dlog(ctx, "process_work_frame() interpolate:%f/256\n", interpolate);
> -    copy_src1 = s->srce[s->crnt];
> +    src1 = s->crnt;
>     if (interpolate > s->interp_end) {
>         ff_dlog(ctx, "process_work_frame() source is:NEXT\n");
> -        copy_src1 = s->srce[s->next];
> +        src1 = s->next;
>     }
>     if (s->srce[s->prev] && interpolate < -s->interp_end) {
>         ff_dlog(ctx, "process_work_frame() source is:PREV\n");
> -        copy_src1 = s->srce[s->prev];
> +        src1 = s->prev;
>     }
>
>     // decide whether to blend two frames
>     if ((interpolate >= s->interp_start && interpolate <= s->interp_end) || (interpolate <= -s->interp_start && interpolate >= -s->interp_end)) {
> -        AVFrame *copy_src2;
> -
>         if (interpolate > 0) {
>             ff_dlog(ctx, "process_work_frame() interpolate source is:NEXT\n");
> -            copy_src2 = s->srce[s->next];
> +            src2 = s->next;
>         } else {
>             ff_dlog(ctx, "process_work_frame() interpolate source is:PREV\n");
> -            copy_src2 = s->srce[s->prev];
> +            src2 = s->prev;
>         }
> -        if (blend_frames(ctx, interpolate, copy_src1, copy_src2))
> +        if (blend_frames(ctx, interpolate, src1, src2))
>             goto copy_done;
>         else
>             ff_dlog(ctx, "process_work_frame() CUT - DON'T INTERPOLATE\n");
> @@ -414,7 +419,7 @@ static int process_work_frame(AVFilterContext *ctx, int stop)
>
>     ff_dlog(ctx, "process_work_frame() COPY to the work frame\n");
>     // copy the frame we decided is our base source
> -    s->work = av_frame_clone(copy_src1);
> +    s->work = av_frame_clone(s->srce[src1]);
>     if (!s->work)
>         return AVERROR(ENOMEM);
> 
> @@ -504,6 +509,7 @@ static void set_work_frame_pts(AVFilterContext *ctx)
> static av_cold int init(AVFilterContext *ctx)
> {
>     FrameRateContext *s = ctx->priv;
> +    int i;
>
>     s->dest_frame_num = 0;
> 
> @@ -513,6 +519,9 @@ static av_cold int init(AVFilterContext *ctx)
>     s->next = s->crnt - 1;
>     s->prev = s->crnt + 1;
> 
> +    for (i = 0; i < N_SRCE; i++)
> +        s->scre_score[i] = -1.0;
> +
>     return 0;
> }
> 
> -- 
> 2.13.6
>
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