[FFmpeg-devel] [PATCH 1/2] colorbalance filter

Paul B Mahol onemda at gmail.com
Thu Apr 18 16:26:50 CEST 2013


On 4/18/13, Stefano Sabatini <stefasab at gmail.com> wrote:
> On date Wednesday 2013-04-17 00:32:27 +0000, Paul B Mahol encoded:
>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>> ---
>>  doc/filters.texi              |  27 +++++
>>  libavfilter/Makefile          |   1 +
>>  libavfilter/allfilters.c      |   1 +
>>  libavfilter/vf_colorbalance.c | 222
>> ++++++++++++++++++++++++++++++++++++++++++
>>  4 files changed, 251 insertions(+)
>>  create mode 100644 libavfilter/vf_colorbalance.c
>>
>> diff --git a/doc/filters.texi b/doc/filters.texi
>> index 5228c82..685791b 100644
>> --- a/doc/filters.texi
>> +++ b/doc/filters.texi
>> @@ -2051,6 +2051,33 @@
>> boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chrom
>>  @end example
>>  @end itemize
>>
>> + at section colorbalance
>> +Modify intensity of primary colors (red, green and blue) of input image.
>> +
>
>> +The filter allows an image to be adjusted in the shadows, midtones or
>> highlights
>> +regions for the red-cyan, green-magenta or blue-yellow balance.
>
> Add something like the following somewhere:
> A positive a positive adjustment value shifts the balance towards the
> primary color, a negative value towards the complementary color.

Added.

>
>> +
>> +The filter accepts the following options:
>> +
>> + at table @option
>> + at item rs
>> + at item gs
>> + at item bs
>
>> +Adjust red, green and blue shadows (darkest pixels).
>
> Nit: lowtones could be a better term, but feel free to keep
> consistency with Gimp.
>
>> +
>> + at item rm
>> + at item gm
>> + at item bm
>> +Adjust red, green and blue midtones (medium pixels).
>> +
>> + at item rh
>> + at item gh
>> + at item bh
>> +Adjust red, green and blue highlights (brightest pixels).
>> +
>> +Allowed range is from -100 to 100, default is 0.
>
> Examples are still welcome, especially considering that the
> documentation is not very specific.

Added.

>
>> + at end table
>> +
>>  @section colormatrix
>>
>>  Convert color matrix.
>> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
>> index 949972d..0927986 100644
>> --- a/libavfilter/Makefile
>> +++ b/libavfilter/Makefile
>> @@ -104,6 +104,7 @@ OBJS-$(CONFIG_BLACKDETECT_FILTER)            +=
>> vf_blackdetect.o
>>  OBJS-$(CONFIG_BLACKFRAME_FILTER)             += vf_blackframe.o
>>  OBJS-$(CONFIG_BLEND_FILTER)                  += vf_blend.o
>>  OBJS-$(CONFIG_BOXBLUR_FILTER)                += vf_boxblur.o
>> +OBJS-$(CONFIG_COLORBALANCE_FILTER)           += vf_colorbalance.o
>>  OBJS-$(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 95bd270..bebbf2b 100644
>> --- a/libavfilter/allfilters.c
>> +++ b/libavfilter/allfilters.c
>> @@ -102,6 +102,7 @@ void avfilter_register_all(void)
>>      REGISTER_FILTER(BLACKFRAME,     blackframe,     vf);
>>      REGISTER_FILTER(BLEND,          blend,          vf);
>>      REGISTER_FILTER(BOXBLUR,        boxblur,        vf);
>> +    REGISTER_FILTER(COLORBALANCE,   colorbalance,   vf);
>>      REGISTER_FILTER(COLORMATRIX,    colormatrix,    vf);
>>      REGISTER_FILTER(COPY,           copy,           vf);
>>      REGISTER_FILTER(CROP,           crop,           vf);
>> diff --git a/libavfilter/vf_colorbalance.c
>> b/libavfilter/vf_colorbalance.c
>> new file mode 100644
>> index 0000000..73c6227
>> --- /dev/null
>> +++ b/libavfilter/vf_colorbalance.c
>> @@ -0,0 +1,222 @@
>> +/*
>> + * 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/pixdesc.h"
>> +#include "avfilter.h"
>> +#include "drawutils.h"
>> +#include "formats.h"
>> +#include "internal.h"
>> +#include "video.h"
>> +
>> +typedef struct {
>> +    double shadows;
>> +    double midtones;
>> +    double highlights;
>> +} Range;
>> +
>> +typedef struct {
>> +    const AVClass *class;
>> +    Range cyan_red;
>> +    Range magenta_green;
>> +    Range yellow_blue;
>> +
>
>> +    uint8_t lookup[3][256];
>
> doxy?

Really?

>
>> +
>> +    uint8_t rgba_map[4];
>> +    int step;
>> +} ColorBalanceContext;
>> +
>> +#define OFFSET(x) offsetof(ColorBalanceContext, x)
>> +#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
>> +static const AVOption colorbalance_options[] = {
>> +    { "rs", "set red shadows",      OFFSET(cyan_red.shadows),
>> AV_OPT_TYPE_DOUBLE, {.dbl=0}, -100, 100, FLAGS },
>> +    { "gs", "set green shadows",    OFFSET(magenta_green.shadows),
>> AV_OPT_TYPE_DOUBLE, {.dbl=0}, -100, 100, FLAGS },
>> +    { "bs", "set blue shadows",     OFFSET(yellow_blue.shadows),
>> AV_OPT_TYPE_DOUBLE, {.dbl=0}, -100, 100, FLAGS },
>> +    { "rm", "set red midtones",     OFFSET(cyan_red.midtones),
>> AV_OPT_TYPE_DOUBLE, {.dbl=0}, -100, 100, FLAGS },
>> +    { "gm", "set green midtones",   OFFSET(magenta_green.midtones),
>> AV_OPT_TYPE_DOUBLE, {.dbl=0}, -100, 100, FLAGS },
>> +    { "bm", "set blue midtones",    OFFSET(yellow_blue.midtones),
>> AV_OPT_TYPE_DOUBLE, {.dbl=0}, -100, 100, FLAGS },
>> +    { "rh", "set red highlights",   OFFSET(cyan_red.highlights),
>> AV_OPT_TYPE_DOUBLE, {.dbl=0}, -100, 100, FLAGS },
>> +    { "gh", "set green highlights", OFFSET(magenta_green.highlights),
>> AV_OPT_TYPE_DOUBLE, {.dbl=0}, -100, 100, FLAGS },
>> +    { "bh", "set blue highlights",  OFFSET(yellow_blue.highlights),
>> AV_OPT_TYPE_DOUBLE, {.dbl=0}, -100, 100, FLAGS },
>> +    { NULL }
>> +};
>> +
>> +AVFILTER_DEFINE_CLASS(colorbalance);
>> +
>> +static int query_formats(AVFilterContext *ctx)
>> +{
>> +    static const enum AVPixelFormat pix_fmts[] = {
>> +        AV_PIX_FMT_RGB24, AV_PIX_FMT_BGR24,
>> +        AV_PIX_FMT_RGBA,  AV_PIX_FMT_BGRA,
>> +        AV_PIX_FMT_ABGR,  AV_PIX_FMT_ARGB,
>> +        AV_PIX_FMT_0BGR,  AV_PIX_FMT_0RGB,
>> +        AV_PIX_FMT_RGB0,  AV_PIX_FMT_BGR0,
>> +        AV_PIX_FMT_NONE
>> +    };
>> +
>> +    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
>> +    return 0;
>> +}
>> +
>> +static int config_output(AVFilterLink *outlink)
>> +{
>> +    AVFilterContext *ctx = outlink->src;
>> +    ColorBalanceContext *cb = ctx->priv;
>> +    const AVPixFmtDescriptor *desc =
>> av_pix_fmt_desc_get(outlink->format);
>> +    double *add[3], *sub[3];
>> +    double *coeff[3][3];
>> +    double *buffer;
>> +    int i, r, g, b;
>> +
>> +    buffer = av_malloc(256 * 3 * 2 * sizeof(double));
>> +    if (!buffer)
>> +        return AVERROR(ENOMEM);
>> +
>> +    for (i = 0; i < 3; i++) {
>> +        add[i] = buffer + 256 * i;
>> +        sub[i] = buffer + 256 * (3 + i);
>> +    }
>> +
>> +    for (i = 0; i < 256; i++) {
>> +        double low = (1.075 - 1 / (i / 16.0 + 1));
>
> low has the minimum value with i=0 and is monotonically increasing
> with i, while I would expect the opposite behavior.

Fixed, it was broken and did not worked at all

>
>> +        double mid = 2.0 / 3.0 * (1 - ((i - 127.0) / 127.0) * ((i -
>> 127.0) / 127.0));
>> +
>> +        add[0][i] = low;
>> +        add[1][i] = mid;
>> +        add[2][255 - i] = low;
>> +        sub[0][255 - i] = low;
>> +        sub[1][i] = mid;
>> +        sub[2][i] = low;
>> +    }
>> +
>> +    coeff[0][0] = cb->cyan_red.shadows         > 0 ? add[0] : sub[0];
>> +    coeff[1][0] = cb->magenta_green.shadows    > 0 ? add[0] : sub[0];
>> +    coeff[2][0] = cb->yellow_blue.shadows      > 0 ? add[0] : sub[0];
>> +    coeff[0][1] = cb->cyan_red.midtones        > 0 ? add[1] : sub[1];
>> +    coeff[1][1] = cb->magenta_green.midtones   > 0 ? add[1] : sub[1];
>> +    coeff[2][1] = cb->yellow_blue.midtones     > 0 ? add[1] : sub[1];
>> +    coeff[0][2] = cb->cyan_red.highlights      > 0 ? add[2] : sub[2];
>> +    coeff[1][2] = cb->magenta_green.highlights > 0 ? add[2] : sub[2];
>> +    coeff[2][2] = cb->yellow_blue.highlights   > 0 ? add[2] : sub[2];
>> +
>> +    for (i = 0; i < 256; i++) {
>> +        r = g = b = i;
>> +
>> +        r = av_clip_uint8(r + cb->cyan_red.shadows         *
>> coeff[0][0][r]);
>> +        r = av_clip_uint8(r + cb->cyan_red.midtones        *
>> coeff[0][1][r]);
>> +        r = av_clip_uint8(r + cb->cyan_red.highlights      *
>> coeff[0][2][r]);
>> +
>> +        g = av_clip_uint8(g + cb->magenta_green.shadows    *
>> coeff[1][0][g]);
>> +        g = av_clip_uint8(g + cb->magenta_green.midtones   *
>> coeff[1][1][g]);
>> +        g = av_clip_uint8(g + cb->magenta_green.highlights *
>> coeff[1][2][g]);
>> +
>> +        b = av_clip_uint8(b + cb->yellow_blue.shadows      *
>> coeff[2][0][b]);
>> +        b = av_clip_uint8(b + cb->yellow_blue.midtones     *
>> coeff[2][1][b]);
>> +        b = av_clip_uint8(b + cb->yellow_blue.highlights   *
>> coeff[2][2][b]);
>> +
>> +        cb->lookup[0][i] = r;
>> +        cb->lookup[1][i] = g;
>> +        cb->lookup[2][i] = b;
>> +    }
>
> named constant in place of 012 (e.g. RGB and LOW/MID/HIGH) may help to
> interpret the code above.

Done.

>
> [...]
>
> No more comments from me, assuming it is consistent with Gimp and
> reasonably tested, thanks.

Applied.

> --
> FFmpeg = Fancy and Fanciful Martial Political Enlightened God
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