[FFmpeg-devel] [PATCH] colorkeymask filter

[Paul B Mahol]

On 5/10/13, Stefano Sabatini <stefasab at gmail.com> wrote:
> On date Wednesday 2013-05-08 14:21:54 +0000, Paul B Mahol encoded:
>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>> ---
>>  libavfilter/Makefile          |   1 +
>>  libavfilter/allfilters.c      |   1 +
>>  libavfilter/vf_colorkeymask.c | 161
>> ++++++++++++++++++++++++++++++++++++++++++
>
> Missing docs.
>
>>  3 files changed, 163 insertions(+)
>>  create mode 100644 libavfilter/vf_colorkeymask.c
>>
>> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
>> index f0e703e..04f9646 100644
>> --- a/libavfilter/Makefile
>> +++ b/libavfilter/Makefile
>> @@ -110,6 +110,7 @@ OBJS-$(CONFIG_BLEND_FILTER)                  +=
>> vf_blend.o
>>  OBJS-$(CONFIG_BOXBLUR_FILTER)                += vf_boxblur.o
>>  OBJS-$(CONFIG_COLORBALANCE_FILTER)           += vf_colorbalance.o
>>  OBJS-$(CONFIG_COLORCHANNELMIXER_FILTER)      += vf_colorchannelmixer.o
>> +OBJS-$(CONFIG_COLORKEYMASK_FILTER)           += vf_colorkeymask.o
>>  OBJS-$(CONFIG_COLORMATRIX_FILTER)            += vf_colormatrix.o
>>  OBJS-$(CONFIG_COPY_FILTER)                   += vf_copy.o
>>  OBJS-$(CONFIG_CROP_FILTER)                   += vf_crop.o
>> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
>> index b8f273d..8d6e2fa 100644
>> --- a/libavfilter/allfilters.c
>> +++ b/libavfilter/allfilters.c
>> @@ -108,6 +108,7 @@ void avfilter_register_all(void)
>>      REGISTER_FILTER(BOXBLUR,        boxblur,        vf);
>>      REGISTER_FILTER(COLORBALANCE,   colorbalance,   vf);
>>      REGISTER_FILTER(COLORCHANNELMIXER, colorchannelmixer, vf);
>> +    REGISTER_FILTER(COLORKEYMASK,   colorkeymask,   vf);
>>      REGISTER_FILTER(COLORMATRIX,    colormatrix,    vf);
>>      REGISTER_FILTER(COPY,           copy,           vf);
>>      REGISTER_FILTER(CROP,           crop,           vf);
>> diff --git a/libavfilter/vf_colorkeymask.c
>> b/libavfilter/vf_colorkeymask.c
>> new file mode 100644
>> index 0000000..7efec0f
>> --- /dev/null
>> +++ b/libavfilter/vf_colorkeymask.c
>> @@ -0,0 +1,161 @@
>> +/*
>> + * Copyright (c) 2013 Paul B Mahol
>> + *
>> + * 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/parseutils.h"
>> +#include "avfilter.h"
>> +#include "drawutils.h"
>> +#include "formats.h"
>> +#include "internal.h"
>> +#include "video.h"
>> +
>> +#define R 0
>> +#define G 1
>> +#define B 2
>> +#define A 3
>> +
>> +typedef struct {
>> +    const AVClass *class;
>> +    char *color_str;
>> +    int rt, gt, bt;
>> +    uint8_t lut[3][256];
>> +    uint8_t rgba_map[4];
>> +} ColorKeyMaskContext;
>> +
>> +#define OFFSET(x) offsetof(ColorKeyMaskContext, x)
>> +#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
>> +static const AVOption colorkeymask_options[] = {
>
>> +    { "color", "set color",   OFFSET(color_str), AV_OPT_TYPE_STRING,
>> {.str="black"}, 0, 0, FLAGS },
>
> I wonder if we should add a color option.
>
>> +    { "r", "set red tolerance",   OFFSET(rt), AV_OPT_TYPE_INT, {.i64=10},
>> 0, 255, FLAGS },
>> +    { "g", "set green tolerance", OFFSET(gt), AV_OPT_TYPE_INT, {.i64=10},
>> 0, 255, FLAGS },
>> +    { "b", "set blue tolerance",  OFFSET(bt), AV_OPT_TYPE_INT, {.i64=10},
>> 0, 255, FLAGS },
>
> 0-1 range?
>
>> +    { NULL }
>> +};
>> +
>> +AVFILTER_DEFINE_CLASS(colorkeymask);
>> +
>> +static av_cold int init(AVFilterContext *ctx)
>> +{
>> +    ColorKeyMaskContext *s = ctx->priv;
>> +    uint8_t rmin, gmin, bmin;
>> +    uint8_t rmax, gmax, bmax;
>> +    uint8_t rgba[4];
>> +    int i, ret;
>> +
>> +    ret = av_parse_color(rgba, s->color_str, -1, ctx);
>> +    if (ret < 0)
>> +        return ret;
>> +
>
>> +    rmin = av_clip_uint8(rgba[R] - s->rt);
>> +    gmin = av_clip_uint8(rgba[G] - s->gt);
>> +    bmin = av_clip_uint8(rgba[B] - s->bt);
>> +    rmax = av_clip_uint8(rgba[R] + s->rt);
>> +    gmax = av_clip_uint8(rgba[G] + s->gt);
>> +    bmax = av_clip_uint8(rgba[B] + s->bt);
>
> There is a better way to do this, by adopting the HSV colorspace so
> that you don't need to cut the interval:
> http://web.archiveorange.com/archive/v/yR2T4tPhfGQVuuTxzOh1

Pointless, its extremly slow.

>
> and enjoy the flames.
>
> Sorry for the spam but the patch was not available in the archive:
> http://ffmpeg.org/pipermail/ffmpeg-devel/2009-June/070428.html

I plan to make it generic (not rgb specific) add trivail documentation
and apply it.

>
> [...]
> --
> FFmpeg = Fantastic and Fast Miracolous Peaceful Egregious Goblin
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