avfilter: add monochrome video filter

Changelog

@@ -71,6 +71,7 @@ version <next>:
 - CRI parser
 - aexciter audio filter
 - exposure video filter
+- monochrome video filter
 
 
 version 4.3:

doc/filters.texi

@@ -14816,6 +14816,33 @@ This filter supports the following commands:
 Syntax is same as option with same name.
 @end table
 
+@section monochrome
+Convert video to gray using custom color filter.
+
+A description of the accepted options follows.
+
+@table @option
+@item cb
+Set the chroma blue spot. Allowed range is from -1 to 1.
+Default value is 0.
+
+@item cr
+Set the chroma red spot. Allowed range is from -1 to 1.
+Default value is 0.
+
+@item size
+Set the color filter size. Allowed range is from .1 to 10.
+Default value is 1.
+
+@item high
+Set the highlights strength. Allowed range is from 0 to 1.
+Default value is 0.
+@end table
+
+@subsection Commands
+
+This filter supports the all above options as @ref{commands}.
+
 @section mpdecimate
 
 Drop frames that do not differ greatly from the previous frame in

libavfilter/Makefile

@@ -332,6 +332,7 @@ OBJS-$(CONFIG_METADATA_FILTER)               += f_metadata.o
 OBJS-$(CONFIG_MIDEQUALIZER_FILTER)           += vf_midequalizer.o framesync.o
 OBJS-$(CONFIG_MINTERPOLATE_FILTER)           += vf_minterpolate.o motion_estimation.o
 OBJS-$(CONFIG_MIX_FILTER)                    += vf_mix.o framesync.o
+OBJS-$(CONFIG_MONOCHROME_FILTER)             += vf_monochrome.o
 OBJS-$(CONFIG_MPDECIMATE_FILTER)             += vf_mpdecimate.o
 OBJS-$(CONFIG_NEGATE_FILTER)                 += vf_lut.o
 OBJS-$(CONFIG_NLMEANS_FILTER)                += vf_nlmeans.o

libavfilter/allfilters.c

@@ -317,6 +317,7 @@ extern AVFilter ff_vf_metadata;
 extern AVFilter ff_vf_midequalizer;
 extern AVFilter ff_vf_minterpolate;
 extern AVFilter ff_vf_mix;
+extern AVFilter ff_vf_monochrome;
 extern AVFilter ff_vf_mpdecimate;
 extern AVFilter ff_vf_negate;
 extern AVFilter ff_vf_nlmeans;

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   7
-#define LIBAVFILTER_VERSION_MINOR 105
+#define LIBAVFILTER_VERSION_MINOR 106
 #define LIBAVFILTER_VERSION_MICRO 100
 
 

libavfilter/vf_monochrome.c

@@ -0,0 +1,314 @@
+/*
+ * Copyright (c) 2021 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 <float.h>
+
+#include "libavutil/opt.h"
+#include "libavutil/imgutils.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+typedef struct MonochromeContext {
+    const AVClass *class;
+
+    float b, r;
+    float size;
+    float high;
+
+    int depth;
+    int subw, subh;
+
+    int (*do_slice)(AVFilterContext *s, void *arg,
+                    int jobnr, int nb_jobs);
+    int (*clear_uv)(AVFilterContext *s, void *arg,
+                    int jobnr, int nb_jobs);
+} MonochromeContext;
+
+static float envelope(const float x)
+{
+    const float beta = 0.6f;
+
+    if (x < beta) {
+        const float tmp = fabsf(x / beta - 1.f);
+
+        return 1.f - tmp * tmp;
+    } else {
+        const float tmp = (1.f - x) / (1.f - beta);
+
+        return tmp * tmp * (3.f - 2.f * tmp);
+    }
+}
+
+static float filter(float b, float r, float u, float v, float size)
+{
+    return expf(-av_clipf(((b - u) * (b - u) +
+                           (r - v) * (r - v)) *
+                            size, 0.f, 1.f));
+}
+
+#define PROCESS()                            \
+    const int cx = x >> subw;                \
+    float y = yptr[x] * imax;                \
+    float u = uptr[cx] * imax - .5f;         \
+    float v = vptr[cx] * imax - .5f;         \
+    float tt, t, ny;                         \
+                                             \
+    ny = filter(b, r, u, v, size);           \
+    tt = envelope(y);                        \
+    t = tt + (1.f - tt) * ihigh;             \
+    ny = (1.f - t) * y + t * ny * y;
+
+static int monochrome_slice8(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
+{
+    MonochromeContext *s = ctx->priv;
+    AVFrame *frame = arg;
+    const int depth = s->depth;
+    const int subw = s->subw;
+    const int subh = s->subh;
+    const float max = (1 << depth) - 1;
+    const float imax = 1.f / max;
+    const int width = frame->width;
+    const int height = frame->height;
+    const int slice_start = (height * jobnr) / nb_jobs;
+    const int slice_end = (height * (jobnr + 1)) / nb_jobs;
+    const int ylinesize = frame->linesize[0];
+    const int ulinesize = frame->linesize[1];
+    const int vlinesize = frame->linesize[2];
+    uint8_t *yptr = frame->data[0] + slice_start * ylinesize;
+    const float ihigh = 1.f - s->high;
+    const float size = 1.f / s->size;
+    const float b = s->b * .5f;
+    const float r = s->r * .5f;
+
+    for (int y = slice_start; y < slice_end; y++) {
+        const int cy = y >> subh;
+        uint8_t *uptr = frame->data[1] + cy * ulinesize;
+        uint8_t *vptr = frame->data[2] + cy * vlinesize;
+
+        for (int x = 0; x < width; x++) {
+            PROCESS()
+
+            yptr[x] = av_clip_uint8(ny * max);
+        }
+
+        yptr += ylinesize;
+    }
+
+    return 0;
+}
+
+static int monochrome_slice16(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
+{
+    MonochromeContext *s = ctx->priv;
+    AVFrame *frame = arg;
+    const int depth = s->depth;
+    const int subw = s->subw;
+    const int subh = s->subh;
+    const float max = (1 << depth) - 1;
+    const float imax = 1.f / max;
+    const int width = frame->width;
+    const int height = frame->height;
+    const int slice_start = (height * jobnr) / nb_jobs;
+    const int slice_end = (height * (jobnr + 1)) / nb_jobs;
+    const int ylinesize = frame->linesize[0] / 2;
+    const int ulinesize = frame->linesize[1] / 2;
+    const int vlinesize = frame->linesize[2] / 2;
+    uint16_t *yptr = (uint16_t *)frame->data[0] + slice_start * ylinesize;
+    const float ihigh = 1.f - s->high;
+    const float size = 1.f / s->size;
+    const float b = s->b * .5f;
+    const float r = s->r * .5f;
+
+    for (int y = slice_start; y < slice_end; y++) {
+        const int cy = y >> subh;
+        uint16_t *uptr = (uint16_t *)frame->data[1] + cy * ulinesize;
+        uint16_t *vptr = (uint16_t *)frame->data[2] + cy * vlinesize;
+
+        for (int x = 0; x < width; x++) {
+            PROCESS()
+
+            yptr[x] = av_clip_uintp2_c(ny * max, depth);
+        }
+
+        yptr += ylinesize;
+    }
+
+    return 0;
+}
+
+static int clear_slice8(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
+{
+    MonochromeContext *s = ctx->priv;
+    AVFrame *frame = arg;
+    const int depth = s->depth;
+    const int half = 1 << (depth - 1);
+    const int subw = s->subw;
+    const int subh = s->subh;
+    const int width = AV_CEIL_RSHIFT(frame->width, subw);
+    const int height = AV_CEIL_RSHIFT(frame->height, subh);
+    const int slice_start = (height * jobnr) / nb_jobs;
+    const int slice_end = (height * (jobnr + 1)) / nb_jobs;
+    const int ulinesize = frame->linesize[1];
+    const int vlinesize = frame->linesize[2];
+
+    for (int y = slice_start; y < slice_end; y++) {
+        uint8_t *uptr = frame->data[1] + y * ulinesize;
+        uint8_t *vptr = frame->data[2] + y * vlinesize;
+
+        memset(uptr, half, width);
+        memset(vptr, half, width);
+    }
+
+    return 0;
+}
+
+static int clear_slice16(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
+{
+    MonochromeContext *s = ctx->priv;
+    AVFrame *frame = arg;
+    const int depth = s->depth;
+    const int half = 1 << (depth - 1);
+    const int subw = s->subw;
+    const int subh = s->subh;
+    const int width = AV_CEIL_RSHIFT(frame->width, subw);
+    const int height = AV_CEIL_RSHIFT(frame->height, subh);
+    const int slice_start = (height * jobnr) / nb_jobs;
+    const int slice_end = (height * (jobnr + 1)) / nb_jobs;
+    const int ulinesize = frame->linesize[1] / 2;
+    const int vlinesize = frame->linesize[2] / 2;
+
+    for (int y = slice_start; y < slice_end; y++) {
+        uint16_t *uptr = (uint16_t *)frame->data[1] + y * ulinesize;
+        uint16_t *vptr = (uint16_t *)frame->data[2] + y * vlinesize;
+
+        for (int x = 0; x < width; x++) {
+            uptr[x] = half;
+            vptr[x] = half;
+        }
+    }
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
+{
+    AVFilterContext *ctx = inlink->dst;
+    MonochromeContext *s = ctx->priv;
+
+    ctx->internal->execute(ctx, s->do_slice, frame, NULL,
+                           FFMIN(frame->height, ff_filter_get_nb_threads(ctx)));
+    ctx->internal->execute(ctx, s->clear_uv, frame, NULL,
+                           FFMIN(frame->height >> s->subh, ff_filter_get_nb_threads(ctx)));
+
+    return ff_filter_frame(ctx->outputs[0], frame);
+}
+
+static av_cold int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pixel_fmts[] = {
+        AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
+        AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
+        AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
+        AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
+        AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P,
+        AV_PIX_FMT_YUVJ411P,
+        AV_PIX_FMT_YUV420P9, AV_PIX_FMT_YUV422P9, AV_PIX_FMT_YUV444P9,
+        AV_PIX_FMT_YUV420P10, AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV444P10,
+        AV_PIX_FMT_YUV440P10,
+        AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV420P12,
+        AV_PIX_FMT_YUV440P12,
+        AV_PIX_FMT_YUV444P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV420P14,
+        AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
+        AV_PIX_FMT_YUVA420P,  AV_PIX_FMT_YUVA422P,   AV_PIX_FMT_YUVA444P,
+        AV_PIX_FMT_YUVA444P9, AV_PIX_FMT_YUVA444P10, AV_PIX_FMT_YUVA444P12, AV_PIX_FMT_YUVA444P16,
+        AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA422P12, AV_PIX_FMT_YUVA422P16,
+        AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA420P16,
+        AV_PIX_FMT_NONE
+    };
+
+    AVFilterFormats *formats = NULL;
+
+    formats = ff_make_format_list(pixel_fmts);
+    if (!formats)
+        return AVERROR(ENOMEM);
+
+    return ff_set_common_formats(ctx, formats);
+}
+
+static av_cold int config_input(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->dst;
+    MonochromeContext *s = ctx->priv;
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+
+    s->depth = desc->comp[0].depth;
+    s->do_slice = s->depth <= 8 ? monochrome_slice8 : monochrome_slice16;
+    s->clear_uv = s->depth <= 8 ? clear_slice8 : clear_slice16;
+    s->subw = desc->log2_chroma_w;
+    s->subh = desc->log2_chroma_h;
+
+    return 0;
+}
+
+static const AVFilterPad monochrome_inputs[] = {
+    {
+        .name           = "default",
+        .type           = AVMEDIA_TYPE_VIDEO,
+        .needs_writable = 1,
+        .filter_frame   = filter_frame,
+        .config_props   = config_input,
+    },
+    { NULL }
+};
+
+static const AVFilterPad monochrome_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+#define OFFSET(x) offsetof(MonochromeContext, x)
+#define VF AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
+
+static const AVOption monochrome_options[] = {
+    { "cb",   "set the chroma blue spot",    OFFSET(b),    AV_OPT_TYPE_FLOAT, {.dbl=0},-1, 1, VF },
+    { "cr",   "set the chroma red spot",     OFFSET(r),    AV_OPT_TYPE_FLOAT, {.dbl=0},-1, 1, VF },
+    { "size", "set the color filter size",   OFFSET(size), AV_OPT_TYPE_FLOAT, {.dbl=1},.1,10, VF },
+    { "high", "set the highlights strength", OFFSET(high), AV_OPT_TYPE_FLOAT, {.dbl=0}, 0, 1, VF },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(monochrome);
+
+AVFilter ff_vf_monochrome = {
+    .name          = "monochrome",
+    .description   = NULL_IF_CONFIG_SMALL("Convert video to gray using custom color filter."),
+    .priv_size     = sizeof(MonochromeContext),
+    .priv_class    = &monochrome_class,
+    .query_formats = query_formats,
+    .inputs        = monochrome_inputs,
+    .outputs       = monochrome_outputs,
+    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
+    .process_command = ff_filter_process_command,
+};