[FFmpeg-devel] [PATCH 1/2] avfilter/vf_colorkey: Add colorkey video filter
Timo Rothenpieler
timo at rothenpieler.org
Sat Jun 13 15:09:07 CEST 2015
---
Changelog | 1 +
MAINTAINERS | 1 +
doc/filters.texi | 39 +++++++++++
libavfilter/Makefile | 1 +
libavfilter/allfilters.c | 1 +
libavfilter/vf_colorkey.c | 169 ++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 212 insertions(+)
create mode 100644 libavfilter/vf_colorkey.c
diff --git a/Changelog b/Changelog
index aa5753e..9a53286 100644
--- a/Changelog
+++ b/Changelog
@@ -2,6 +2,7 @@ Entries are sorted chronologically from oldest to youngest within each release,
releases are sorted from youngest to oldest.
version <next>:
+- colorkey video filter
version 2.7:
diff --git a/MAINTAINERS b/MAINTAINERS
index 795e904..7b239a1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -352,6 +352,7 @@ Filters:
avf_showcqt.c Muhammad Faiz
vf_blend.c Paul B Mahol
vf_colorbalance.c Paul B Mahol
+ vf_colorkey.c Timo Rothenpieler
vf_dejudder.c Nicholas Robbins
vf_delogo.c Jean Delvare (CC <khali at linux-fr.org>)
vf_drawbox.c/drawgrid Andrey Utkin
diff --git a/doc/filters.texi b/doc/filters.texi
index 54b3464..6437c0c 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -3029,6 +3029,45 @@ colorbalance=rs=.3
@end example
@end itemize
+ at section colorkey
+RGB colorspace color keying.
+
+The filter accepts the following options:
+
+ at table @option
+ at item color
+The color which will be replaced with transparency.
+
+ at item similarity
+Similarity percentage with the key color.
+
+0.01 matches only the exact key color, while 1.0 matches everything.
+
+ at item blend
+Blend percentage.
+
+0.0 makes pixels either fully transparent, or not transparent at all.
+
+Higher values result in semi-transparent pixels, with a higher transparency
+the more similar the pixels color is to the key color.
+ at end table
+
+ at subsection Examples
+
+ at itemize
+ at item
+Make every green pixel in the input image transparent:
+ at example
+ffmpeg -i input.png -vf colorkey=green out.png
+ at end example
+
+ at item
+Overlay a greenscreen-video on top of a static background image.
+ at example
+ffmpeg -i background.png -i video.mp4 -filter_complex "[1:v]colorkey=0x3BBD1E:0.3:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.flv
+ at end example
+ at end itemize
+
@section colorlevels
Adjust video input frames using levels.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index bf5a549..fc9f455 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -102,6 +102,7 @@ OBJS-$(CONFIG_BOXBLUR_FILTER) += vf_boxblur.o
OBJS-$(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_COLORLEVELS_FILTER) += vf_colorlevels.o
OBJS-$(CONFIG_COLORMATRIX_FILTER) += vf_colormatrix.o
OBJS-$(CONFIG_COPY_FILTER) += vf_copy.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 0244585..415ed1b 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -118,6 +118,7 @@ void avfilter_register_all(void)
REGISTER_FILTER(CODECVIEW, codecview, vf);
REGISTER_FILTER(COLORBALANCE, colorbalance, vf);
REGISTER_FILTER(COLORCHANNELMIXER, colorchannelmixer, vf);
+ REGISTER_FILTER(COLORKEY, colorkey, vf);
REGISTER_FILTER(COLORLEVELS, colorlevels, vf);
REGISTER_FILTER(COLORMATRIX, colormatrix, vf);
REGISTER_FILTER(COPY, copy, vf);
diff --git a/libavfilter/vf_colorkey.c b/libavfilter/vf_colorkey.c
new file mode 100644
index 0000000..19e39ec
--- /dev/null
+++ b/libavfilter/vf_colorkey.c
@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 2015 Timo Rothenpieler <timo at rothenpieler.org>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/opt.h"
+#include "libavutil/imgutils.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+typedef struct ColorkeyContext {
+ const AVClass *class;
+
+ /* color offsets rgba */
+ int co[4];
+
+ uint8_t colorkey_rgba[4];
+ float similarity;
+ float blend;
+} ColorkeyContext;
+
+static uint8_t do_colorkey_pixel(ColorkeyContext *ctx, uint8_t r, uint8_t g, uint8_t b)
+{
+ int dr = (int)r - ctx->colorkey_rgba[0];
+ int dg = (int)g - ctx->colorkey_rgba[1];
+ int db = (int)b - ctx->colorkey_rgba[2];
+
+ double diff = sqrt((dr * dr + dg * dg + db * db) / (255.0 * 255.0));
+
+ if (ctx->blend > 0.0001) {
+ return av_clipd((diff - ctx->similarity) / ctx->blend, 0.0, 1.0) * 255.0;
+ } else {
+ return (diff > ctx->similarity) ? 255 : 0;
+ }
+}
+
+static int do_colorkey_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) {
+ o = frame->linesize[0] * y + x * 4;
+
+ frame->data[0][o + ctx->co[3]] =
+ do_colorkey_pixel(ctx,
+ frame->data[0][o + ctx->co[0]],
+ frame->data[0][o + ctx->co[1]],
+ frame->data[0][o + ctx->co[2]]);
+ }
+ }
+
+ return 0;
+}
+
+static int filter_frame(AVFilterLink *link, AVFrame *frame)
+{
+ AVFilterContext *avctx = link->dst;
+ 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, avctx->graph->nb_threads)))
+ return res;
+
+ return ff_filter_frame(avctx->outputs[0], frame);
+}
+
+static av_cold int config_output(AVFilterLink *outlink)
+{
+ AVFilterContext *avctx = outlink->src;
+ ColorkeyContext *ctx = avctx->priv;
+ const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(outlink->format);
+ int i;
+
+ outlink->w = avctx->inputs[0]->w;
+ outlink->h = avctx->inputs[0]->h;
+ outlink->time_base = avctx->inputs[0]->time_base;
+
+ for (i = 0; i < 4; ++i)
+ ctx->co[i] = desc->comp[i].offset_plus1 - 1;
+
+ return 0;
+}
+
+static av_cold int query_formats(AVFilterContext *avctx)
+{
+ static const enum AVPixelFormat pixel_fmts[] = {
+ AV_PIX_FMT_ARGB,
+ AV_PIX_FMT_RGBA,
+ AV_PIX_FMT_ABGR,
+ AV_PIX_FMT_BGRA,
+ AV_PIX_FMT_NONE
+ };
+
+ AVFilterFormats *formats = NULL;
+
+ formats = ff_make_format_list(pixel_fmts);
+ if (!formats)
+ return AVERROR(ENOMEM);
+
+ return ff_set_common_formats(avctx, formats);
+}
+
+static const AVFilterPad colorkey_inputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .filter_frame = filter_frame,
+ },
+ { NULL }
+};
+
+static const AVFilterPad colorkey_outputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .config_props = config_output,
+ },
+ { NULL }
+};
+
+#define OFFSET(x) offsetof(ColorkeyContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+
+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 },
+ { "blend", "set the colorkey key blend value", OFFSET(blend), AV_OPT_TYPE_FLOAT, { .dbl = 0.0 }, 0.0, 1.0, FLAGS },
+ { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(colorkey);
+
+AVFilter ff_vf_colorkey = {
+ .name = "colorkey",
+ .description = NULL_IF_CONFIG_SMALL("colorkey filter"),
+ .priv_size = sizeof(ColorkeyContext),
+ .priv_class = &colorkey_class,
+ .query_formats = query_formats,
+ .inputs = colorkey_inputs,
+ .outputs = colorkey_outputs,
+ .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
+};
--
2.4.3
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