[FFmpeg-devel] [PATCH] avfilter/vf_chromakey: Add chromakey video filter
Paul B Mahol
onemda at gmail.com
Fri Sep 18 14:36:46 CEST 2015
On 9/18/15, Timo Rothenpieler <timo at rothenpieler.org> wrote:
> ---
> Changelog | 1 +
> MAINTAINERS | 1 +
> doc/filters.texi | 45 ++++++++++
> libavfilter/Makefile | 1 +
> libavfilter/allfilters.c | 1 +
> libavfilter/version.h | 2 +-
> libavfilter/vf_chromakey.c | 211
> +++++++++++++++++++++++++++++++++++++++++++++
> 7 files changed, 261 insertions(+), 1 deletion(-)
> create mode 100644 libavfilter/vf_chromakey.c
>
> diff --git a/Changelog b/Changelog
> index 653317f..db9064d 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -7,6 +7,7 @@ version <next>:
> - ocr filter
> - alimiter filter
> - stereowiden filter
> +- chromakey filter
>
>
> version 2.8:
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 4a50430..12da0cd 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -359,6 +359,7 @@ Filters:
> avf_avectorscope.c Paul B Mahol
> avf_showcqt.c Muhammad Faiz
> vf_blend.c Paul B Mahol
> + vf_chromakey.c Timo Rothenpieler
> vf_colorchannelmixer.c Paul B Mahol
> vf_colorbalance.c Paul B Mahol
> vf_colorkey.c Timo Rothenpieler
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 4a55e59..0446204 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -3556,6 +3556,51 @@
> boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chrom
> @end example
> @end itemize
>
> + at section chromakey
> +YUV colorspace color/chroma 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 item yuv
> +Signals that the color passed is already in YUV instead of RGB.
> +
> +Litteral colors like "green" or "red" don't make sense with this enabled
> anymore.
> +This can be used to pass exact YUV values as hexadecimal numbers.
> + 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 chromakey=green out.png
> + at end example
> +
> + at item
> +Overlay a greenscreen-video on top of a static black background.
> + at example
> +ffmpeg -f lavfi -i color=c=black:s=1280x720 -i video.mp4 -shortest
> -filter_complex
> "[1:v]chromakey=0x70de77:0.1:0.2[ckout];[0:v][ckout]overlay[out]" -map
> "[out]" output.mkv
> + at end example
> + at end itemize
> +
> @section codecview
>
> Visualize information exported by some codecs.
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index 05effd6..2aa8603 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -102,6 +102,7 @@ OBJS-$(CONFIG_BLACKDETECT_FILTER) +=
> vf_blackdetect.o
> OBJS-$(CONFIG_BLACKFRAME_FILTER) += vf_blackframe.o
> OBJS-$(CONFIG_BLEND_FILTER) += vf_blend.o dualinput.o
> framesync.o
> OBJS-$(CONFIG_BOXBLUR_FILTER) += vf_boxblur.o
> +OBJS-$(CONFIG_CHROMAKEY_FILTER) += vf_chromakey.o
> OBJS-$(CONFIG_CODECVIEW_FILTER) += vf_codecview.o
> OBJS-$(CONFIG_COLORBALANCE_FILTER) += vf_colorbalance.o
> OBJS-$(CONFIG_COLORCHANNELMIXER_FILTER) += vf_colorchannelmixer.o
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index cab4564..5075fca 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -124,6 +124,7 @@ void avfilter_register_all(void)
> REGISTER_FILTER(BLACKFRAME, blackframe, vf);
> REGISTER_FILTER(BLEND, blend, vf);
> REGISTER_FILTER(BOXBLUR, boxblur, vf);
> + REGISTER_FILTER(CHROMAKEY, chromakey, vf);
> REGISTER_FILTER(CODECVIEW, codecview, vf);
> REGISTER_FILTER(COLORBALANCE, colorbalance, vf);
> REGISTER_FILTER(COLORCHANNELMIXER, colorchannelmixer, vf);
> diff --git a/libavfilter/version.h b/libavfilter/version.h
> index e918184..9d44fd0 100644
> --- a/libavfilter/version.h
> +++ b/libavfilter/version.h
> @@ -30,7 +30,7 @@
> #include "libavutil/version.h"
>
> #define LIBAVFILTER_VERSION_MAJOR 6
> -#define LIBAVFILTER_VERSION_MINOR 5
> +#define LIBAVFILTER_VERSION_MINOR 6
> #define LIBAVFILTER_VERSION_MICRO 100
>
> #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
> diff --git a/libavfilter/vf_chromakey.c b/libavfilter/vf_chromakey.c
> new file mode 100644
> index 0000000..4809e39
> --- /dev/null
> +++ b/libavfilter/vf_chromakey.c
> @@ -0,0 +1,211 @@
> +/*
> + * 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 ChromakeyContext {
> + const AVClass *class;
> +
> + uint8_t chromakey_rgba[4];
> + uint8_t chromakey_uv[2];
> +
> + float similarity;
> + float blend;
> +
> + int is_yuv;
> +} ChromakeyContext;
> +
> +static uint8_t do_chromakey_pixel(ChromakeyContext *ctx, uint8_t u[9],
> uint8_t v[9])
> +{
> + double diff = 0.0;
> + int du, dv, i;
> +
> + for (i = 0; i < 9; ++i) {
> + du = (int)u[i] - ctx->chromakey_uv[0];
> + dv = (int)v[i] - ctx->chromakey_uv[1];
> +
> + diff += sqrt((du * du + dv * dv) / (255.0 * 255.0));
> + }
> +
> + diff /= 9.0;
> +
> + 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 void get_pixel_uv(AVFrame *frame, int x, int y, uint8_t *u, uint8_t
> *v)
> +{
> + if (x < 0 || x >= frame->width || y < 0 || y >= frame->height) {
> + *u = 0;
> + *v = 0;
> + return;
> + }
> +
> + if (frame->format == AV_PIX_FMT_YUVA420P || frame->format ==
> AV_PIX_FMT_YUVA422P) {
> + x /= 2;
> + }
> +
> + if (frame->format == AV_PIX_FMT_YUVA420P) {
> + y /= 2;
> + }
> +
> + *u = frame->data[1][frame->linesize[1] * y + x];
> + *v = frame->data[2][frame->linesize[2] * y + x];
> +}
> +
> +static int do_chromakey_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;
> +
> + ChromakeyContext *ctx = avctx->priv;
> +
> + int x, y, xo, yo;
> + uint8_t u[9], v[9];
> +
> + for (y = slice_start; y < slice_end; ++y) {
> + for (x = 0; x < frame->width; ++x) {
> + for (yo = 0; yo < 3; ++yo) {
> + for (xo = 0; xo < 3; ++xo) {
> + get_pixel_uv(frame, x + xo - 1, y + yo - 1, &u[yo * 3 +
> xo], &v[yo * 3 + xo]);
> + }
> + }
> +
> + frame->data[3][frame->linesize[3] * y + x] =
> do_chromakey_pixel(ctx, u, v);
> + }
> + }
> +
> + 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_chromakey_slice, frame,
> NULL, FFMIN(frame->height, avctx->graph->nb_threads)))
> + return res;
> +
> + return ff_filter_frame(avctx->outputs[0], frame);
> +}
> +
> +#define FIXNUM(x) ((int) ((x) * (1 << 10) + 0.5))
> +#define RGB_TO_U(rgb) (((- FIXNUM(0.16874) * rgb[0] - FIXNUM(0.33126) *
> rgb[1] + FIXNUM(0.50000) * rgb[2] + (1 << 9) - 1) >> 10) + 128)
> +#define RGB_TO_V(rgb) ((( FIXNUM(0.50000) * rgb[0] - FIXNUM(0.41869) *
> rgb[1] - FIXNUM(0.08131) * rgb[2] + (1 << 9) - 1) >> 10) + 128)
> +
> +static av_cold int initialize_chromakey(AVFilterContext *avctx)
> +{
> + ChromakeyContext *ctx = avctx->priv;
> +
> + if (ctx->is_yuv) {
> + ctx->chromakey_uv[0] = ctx->chromakey_rgba[1];
> + ctx->chromakey_uv[1] = ctx->chromakey_rgba[2];
> + } else {
> + ctx->chromakey_uv[0] = RGB_TO_U(ctx->chromakey_rgba);
> + ctx->chromakey_uv[1] = RGB_TO_V(ctx->chromakey_rgba);
> + }
> +
> + return 0;
> +}
> +
> +static av_cold int config_output(AVFilterLink *outlink)
> +{
> + AVFilterContext *avctx = outlink->src;
> +
> + outlink->w = avctx->inputs[0]->w;
> + outlink->h = avctx->inputs[0]->h;
> + outlink->time_base = avctx->inputs[0]->time_base;
> +
> + return 0;
> +}
This function is not needed, please remove.
> +
> +static av_cold int query_formats(AVFilterContext *avctx)
> +{
> + static const enum AVPixelFormat pixel_fmts[] = {
> + AV_PIX_FMT_YUVA420P,
> + AV_PIX_FMT_YUVA422P,
> + AV_PIX_FMT_YUVA444P,
> + 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 chromakey_inputs[] = {
> + {
> + .name = "default",
> + .type = AVMEDIA_TYPE_VIDEO,
> + .filter_frame = filter_frame,
nit+++++++++++++++++++++: You could align this vertically.
> + },
> + { NULL }
> +};
> +
> +static const AVFilterPad chromakey_outputs[] = {
> + {
> + .name = "default",
> + .type = AVMEDIA_TYPE_VIDEO,
> + .config_props = config_output,
Also not needed.
> + },
> + { NULL }
> +};
> +
> +#define OFFSET(x) offsetof(ChromakeyContext, x)
> +#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
> +
> +static const AVOption chromakey_options[] = {
> + { "color", "set the chromakey key color", OFFSET(chromakey_rgba),
> AV_OPT_TYPE_COLOR, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
> + { "similarity", "set the chromakey similarity value",
> OFFSET(similarity), AV_OPT_TYPE_FLOAT, { .dbl = 0.01 }, 0.01, 1.0, FLAGS },
> + { "blend", "set the chromakey key blend value", OFFSET(blend),
> AV_OPT_TYPE_FLOAT, { .dbl = 0.0 }, 0.0, 1.0, FLAGS },
> + { "yuv", "color parameter is in yuv instead of rgb", OFFSET(is_yuv),
> AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },
> + { NULL }
> +};
> +
> +AVFILTER_DEFINE_CLASS(chromakey);
> +
> +AVFilter ff_vf_chromakey = {
> + .name = "chromakey",
> + .description = NULL_IF_CONFIG_SMALL("Turns a certain color into
> transparency. Operates on YUV colors."),
> + .priv_size = sizeof(ChromakeyContext),
> + .priv_class = &chromakey_class,
> + .init = initialize_chromakey,
> + .query_formats = query_formats,
> + .inputs = chromakey_inputs,
> + .outputs = chromakey_outputs,
> + .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC |
> AVFILTER_FLAG_SLICE_THREADS,
> +};
> --
> 2.5.0
Otherwise looks good, gonna test it.
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