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

Paul B Mahol onemda at gmail.com
Sun Jan 13 20:18:33 EET 2019


Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
 doc/filters.texi          | 14 ++++++
 libavfilter/Makefile      |  1 +
 libavfilter/allfilters.c  |  1 +
 libavfilter/vf_colorkey.c | 93 ++++++++++++++++++++++++++++++++++++++-
 4 files changed, 108 insertions(+), 1 deletion(-)

diff --git a/doc/filters.texi b/doc/filters.texi
index d06dfe089f..2aa122cc77 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -6533,6 +6533,20 @@ 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 end table
+
 @section colorlevels
 
 Adjust video input frames using levels.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 8283389f6e..5925b4bb03 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -176,6 +176,7 @@ OBJS-$(CONFIG_CODECVIEW_FILTER)              += vf_codecview.o
 OBJS-$(CONFIG_COLORBALANCE_FILTER)           += vf_colorbalance.o
 OBJS-$(CONFIG_COLORCHANNELMIXER_FILTER)      += vf_colorchannelmixer.o
 OBJS-$(CONFIG_COLORKEY_FILTER)               += vf_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 b91cff2ce7..0e0e12a5e0 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -165,6 +165,7 @@ extern AVFilter ff_vf_codecview;
 extern AVFilter ff_vf_colorbalance;
 extern AVFilter ff_vf_colorchannelmixer;
 extern AVFilter ff_vf_colorkey;
+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..ea54e367b7 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 +80,64 @@ 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;
+
+            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;
+
+                frame->data[0][o + ctx->co[0]] = a;
+                frame->data[0][o + ctx->co[1]] = a;
+                frame->data[0][o + ctx->co[2]] = a;
+            }
+        }
+    }
+
+    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);
@@ -163,7 +215,46 @@ 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,
 };
+
+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 },
+    { 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,
+};
-- 
2.17.1



More information about the ffmpeg-devel mailing list