[FFmpeg-devel] [PATCH] avfilter: add colorhold filter

Timo Rothenpieler timo at rothenpieler.org
Sat May 11 18:51:53 EEST 2019


On 04.05.2019 16:13, Paul B Mahol wrote:
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
>   doc/filters.texi          |  18 +++++++
>   libavfilter/Makefile      |   1 +
>   libavfilter/allfilters.c  |   1 +
>   libavfilter/vf_colorkey.c | 102 +++++++++++++++++++++++++++++++++++++-
>   4 files changed, 121 insertions(+), 1 deletion(-)
> 
> diff --git a/doc/filters.texi b/doc/filters.texi
> index cd82869849..1ac37a32b8 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -6723,6 +6723,24 @@ ffmpeg -i background.png -i video.mp4 -filter_complex "[1:v]colorkey=0x3BBD1E:0.
>   @end example
>   @end itemize
>   
> + at section colorhold
> +Remove all color information for all RGB colors except for certain one.
> +
> +The filter accepts the following options:
> +
> + at table @option
> + at item color
> +The color which will not be replaced with neutral gray.
> +
> + at item similarity
> +Similarity percentage with the above color.
> +0.01 matches only the exact key color, while 1.0 matches everything.
> +
> + at item blend
> +Blend percentage. 0.0 makes pixels fully gray.
> +Higher values result in more preserved color.
> + at end table
> +
>   @section colorlevels
>   
>   Adjust video input frames using levels.
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index 59d12ce069..b41304d480 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -179,6 +179,7 @@ OBJS-$(CONFIG_COLORCHANNELMIXER_FILTER)      += vf_colorchannelmixer.o
>   OBJS-$(CONFIG_COLORKEY_FILTER)               += vf_colorkey.o
>   OBJS-$(CONFIG_COLORKEY_OPENCL_FILTER)        += vf_colorkey_opencl.o opencl.o \
>                                                   opencl/colorkey.o
> +OBJS-$(CONFIG_COLORHOLD_FILTER)              += vf_colorkey.o
>   OBJS-$(CONFIG_COLORLEVELS_FILTER)            += vf_colorlevels.o
>   OBJS-$(CONFIG_COLORMATRIX_FILTER)            += vf_colormatrix.o
>   OBJS-$(CONFIG_COLORSPACE_FILTER)             += vf_colorspace.o colorspace.o colorspacedsp.o
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index ae725cb0e0..9bdfa7d1bc 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -167,6 +167,7 @@ extern AVFilter ff_vf_colorbalance;
>   extern AVFilter ff_vf_colorchannelmixer;
>   extern AVFilter ff_vf_colorkey;
>   extern AVFilter ff_vf_colorkey_opencl;
> +extern AVFilter ff_vf_colorhold;
>   extern AVFilter ff_vf_colorlevels;
>   extern AVFilter ff_vf_colormatrix;
>   extern AVFilter ff_vf_colorspace;
> diff --git a/libavfilter/vf_colorkey.c b/libavfilter/vf_colorkey.c
> index 3d65e59d42..b546cd4122 100644
> --- a/libavfilter/vf_colorkey.c
> +++ b/libavfilter/vf_colorkey.c
> @@ -34,6 +34,9 @@ typedef struct ColorkeyContext {
>       uint8_t colorkey_rgba[4];
>       float similarity;
>       float blend;
> +
> +    int (*do_slice)(AVFilterContext *ctx, void *arg,
> +                    int jobnr, int nb_jobs);
>   } ColorkeyContext;
>   
>   static uint8_t do_colorkey_pixel(ColorkeyContext *ctx, uint8_t r, uint8_t g, uint8_t b)
> @@ -77,15 +80,65 @@ static int do_colorkey_slice(AVFilterContext *avctx, void *arg, int jobnr, int n
>       return 0;
>   }
>   
> +static int do_colorhold_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
> +{
> +    AVFrame *frame = arg;
> +
> +    const int slice_start = (frame->height * jobnr) / nb_jobs;
> +    const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
> +
> +    ColorkeyContext *ctx = avctx->priv;
> +
> +    int o, x, y;
> +
> +    for (y = slice_start; y < slice_end; ++y) {
> +        for (x = 0; x < frame->width; ++x) {
> +            int t, r, g, b;

Nit, but I'd prefer to not mix "declaration at top" with intermittent 
declaration of vars.
In this case, I'd just put o down here as well.

> +            o = frame->linesize[0] * y + x * 4;
> +            r = frame->data[0][o + ctx->co[0]];
> +            g = frame->data[0][o + ctx->co[1]];
> +            b = frame->data[0][o + ctx->co[2]];
> +
> +            t = do_colorkey_pixel(ctx, r, g, b);
> +
> +            if (t > 0) {
> +                int a = (r + g + b) / 3;
> +                int rt = 255 - t;
> +
> +                frame->data[0][o + ctx->co[0]] = (a * t + r * rt + 127) >> 8;
> +                frame->data[0][o + ctx->co[1]] = (a * t + g * rt + 127) >> 8;
> +                frame->data[0][o + ctx->co[2]] = (a * t + b * rt + 127) >> 8;
> +            }
> +        }
> +    }
> +
> +    return 0;
> +}
> +
> +static av_cold int init_filter(AVFilterContext *avctx)
> +{
> +    ColorkeyContext *ctx = avctx->priv;
> +
> +    if (!strcmp(avctx->filter->name, "colorkey")) {
> +        ctx->do_slice = do_colorkey_slice;
> +    } else {
> +        ctx->do_slice = do_colorhold_slice;
> +    }
> +
> +    return 0;
> +}
> +
>   static int filter_frame(AVFilterLink *link, AVFrame *frame)
>   {
>       AVFilterContext *avctx = link->dst;
> +    ColorkeyContext *ctx = avctx->priv;
>       int res;
>   
>       if (res = av_frame_make_writable(frame))
>           return res;
>   
> -    if (res = avctx->internal->execute(avctx, do_colorkey_slice, frame, NULL, FFMIN(frame->height, ff_filter_get_nb_threads(avctx))))
> +    if (res = avctx->internal->execute(avctx, ctx->do_slice, frame, NULL, FFMIN(frame->height, ff_filter_get_nb_threads(avctx))))
>           return res;
>   
>       return ff_filter_frame(avctx->outputs[0], frame);
> @@ -148,6 +201,8 @@ static const AVFilterPad colorkey_outputs[] = {
>   #define OFFSET(x) offsetof(ColorkeyContext, x)
>   #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
>   
> +#if CONFIG_COLORKEY_FILTER

Shouldn't this also cover at least colorkey_inputs and colorkey_outputs, 
since they'd be unused otherwise?

>   static const AVOption colorkey_options[] = {
>       { "color", "set the colorkey key color", OFFSET(colorkey_rgba), AV_OPT_TYPE_COLOR, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
>       { "similarity", "set the colorkey similarity value", OFFSET(similarity), AV_OPT_TYPE_FLOAT, { .dbl = 0.01 }, 0.01, 1.0, FLAGS },
> @@ -163,7 +218,52 @@ AVFilter ff_vf_colorkey = {
>       .priv_size     = sizeof(ColorkeyContext),
>       .priv_class    = &colorkey_class,
>       .query_formats = query_formats,
> +    .init          = init_filter,
>       .inputs        = colorkey_inputs,
>       .outputs       = colorkey_outputs,
>       .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
>   };
> +
> +#endif /* CONFIG_COLORKEY_FILTER */
> +#if CONFIG_COLORHOLD_FILTER
> +
> +static const AVFilterPad colorhold_inputs[] = {
> +    {
> +        .name = "default",
> +        .type = AVMEDIA_TYPE_VIDEO,
> +        .filter_frame = filter_frame,
> +    },
> +    { NULL }
> +};
> +
> +static const AVFilterPad colorhold_outputs[] = {
> +    {
> +        .name = "default",
> +        .type = AVMEDIA_TYPE_VIDEO,
> +        .config_props = config_output,
> +    },
> +    { NULL }
> +};
> +
> +static const AVOption colorhold_options[] = {
> +    { "color", "set the colorhold key color", OFFSET(colorkey_rgba), AV_OPT_TYPE_COLOR, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
> +    { "similarity", "set the colorhold similarity value", OFFSET(similarity), AV_OPT_TYPE_FLOAT, { .dbl = 0.01 }, 0.01, 1.0, FLAGS },
> +    { "blend", "set the colorhold blend value", OFFSET(blend), AV_OPT_TYPE_FLOAT, { .dbl = 0.0 }, 0.0, 1.0, FLAGS },
> +    { NULL }
> +};
> +
> +AVFILTER_DEFINE_CLASS(colorhold);
> +
> +AVFilter ff_vf_colorhold = {
> +    .name          = "colorhold",
> +    .description   = NULL_IF_CONFIG_SMALL("Turns a certain color range into gray. Operates on RGB colors."),
> +    .priv_size     = sizeof(ColorkeyContext),
> +    .priv_class    = &colorhold_class,
> +    .query_formats = query_formats,
> +    .init          = init_filter,
> +    .inputs        = colorhold_inputs,
> +    .outputs       = colorhold_outputs,
> +    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
> +};
> +
> +#endif /* CONFIG_COLORHOLD_FILTER */
> 

Missing a version bump.

LGTM to me otherwise.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 4538 bytes
Desc: S/MIME Cryptographic Signature
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20190511/a7b4d0d0/attachment.bin>


More information about the ffmpeg-devel mailing list