avfilter: add pseudocolor filter

Changelog

@@ -32,6 +32,7 @@ version <next>:
 - unpremultiply video filter
 - tlut2 video filter
 - floodfill video filter
+- pseudocolor video filter
 
 version 3.3:
 - CrystalHD decoder moved to new decode API

doc/filters.texi

@@ -11785,6 +11785,51 @@ Set value which will be multiplied with filtered result.
 Set value which will be added to filtered result.
 @end table
 
+@section pseudocolor
+
+Alter frame colors in video with pseudocolors.
+
+This filter accept the following options:
+
+@table @option
+@item c0
+set pixel first component expression
+
+@item c1
+set pixel second component expression
+
+@item c2
+set pixel third component expression
+
+@item c3
+set pixel fourth component expression, corresponds to the alpha component
+
+@item i
+set component to use as base for altering colors
+@end table
+
+Each of them specifies the expression to use for computing the lookup table for
+the corresponding pixel component values.
+
+The expressions can contain the following constants and functions:
+
+@table @option
+@item w
+@item h
+The input width and height.
+
+@item val
+The input value for the pixel component.
+
+@item ymin, umin, vmin, amin
+The minimum allowed component value.
+
+@item ymax, umax, vmax, amax
+The maximum allowed component value.
+@end table
+
+All expressions default to "val".
+
 @section psnr
 
 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise

libavfilter/Makefile

@@ -259,6 +259,7 @@ OBJS-$(CONFIG_PP_FILTER)                     += vf_pp.o
 OBJS-$(CONFIG_PP7_FILTER)                    += vf_pp7.o
 OBJS-$(CONFIG_PREMULTIPLY_FILTER)            += vf_premultiply.o framesync2.o
 OBJS-$(CONFIG_PREWITT_FILTER)                += vf_convolution.o
+OBJS-$(CONFIG_PSEUDOCOLOR_FILTER)            += vf_pseudocolor.o
 OBJS-$(CONFIG_PSNR_FILTER)                   += vf_psnr.o dualinput.o framesync.o
 OBJS-$(CONFIG_PULLUP_FILTER)                 += vf_pullup.o
 OBJS-$(CONFIG_QP_FILTER)                     += vf_qp.o

libavfilter/allfilters.c

@@ -270,6 +270,7 @@ static void register_all(void)
     REGISTER_FILTER(PP7,            pp7,            vf);
     REGISTER_FILTER(PREMULTIPLY,    premultiply,    vf);
     REGISTER_FILTER(PREWITT,        prewitt,        vf);
+    REGISTER_FILTER(PSEUDOCOLOR,    pseudocolor,    vf);
     REGISTER_FILTER(PSNR,           psnr,           vf);
     REGISTER_FILTER(PULLUP,         pullup,         vf);
     REGISTER_FILTER(QP,             qp,             vf);

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR  99
+#define LIBAVFILTER_VERSION_MINOR 100
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

libavfilter/vf_pseudocolor.c

+/*
+ * Copyright (c) 2017 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/attributes.h"
+#include "libavutil/common.h"
+#include "libavutil/eval.h"
+#include "libavutil/imgutils.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+static const char *const var_names[] = {
+    "w",        ///< width of the input video
+    "h",        ///< height of the input video
+    "val",      ///< input value for the pixel
+    "ymin",
+    "umin",
+    "vmin",
+    "amin",
+    "ymax",
+    "umax",
+    "vmax",
+    "amax",
+    NULL
+};
+
+enum var_name {
+    VAR_W,
+    VAR_H,
+    VAR_VAL,
+    VAR_YMIN,
+    VAR_UMIN,
+    VAR_VMIN,
+    VAR_AMIN,
+    VAR_YMAX,
+    VAR_UMAX,
+    VAR_VMAX,
+    VAR_AMAX,
+    VAR_VARS_NB
+};
+
+typedef struct PseudoColorContext {
+    const AVClass *class;
+    int max;
+    int index;
+    int nb_planes;
+    int color;
+    int linesize[4];
+    int width[4], height[4];
+    double var_values[VAR_VARS_NB];
+    char   *comp_expr_str[4];
+    AVExpr *comp_expr[4];
+    float lut[4][256];
+} PseudoColorContext;
+
+#define OFFSET(x) offsetof(PseudoColorContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+
+static const AVOption pseudocolor_options[] = {
+    { "c0", "set component #0 expression", OFFSET(comp_expr_str[0]), AV_OPT_TYPE_STRING, {.str="val"},   .flags = FLAGS },
+    { "c1", "set component #1 expression", OFFSET(comp_expr_str[1]), AV_OPT_TYPE_STRING, {.str="val"},   .flags = FLAGS },
+    { "c2", "set component #2 expression", OFFSET(comp_expr_str[2]), AV_OPT_TYPE_STRING, {.str="val"},   .flags = FLAGS },
+    { "c3", "set component #3 expression", OFFSET(comp_expr_str[3]), AV_OPT_TYPE_STRING, {.str="val"},   .flags = FLAGS },
+    { "i",  "set component as base",       OFFSET(index),            AV_OPT_TYPE_INT,    {.i64=0}, 0, 3, .flags = FLAGS },
+    { NULL }
+};
+
+static const enum AVPixelFormat pix_fmts[] = {
+    AV_PIX_FMT_GRAY8,
+    AV_PIX_FMT_YUV444P, AV_PIX_FMT_GBRP,
+    AV_PIX_FMT_YUVA444P, AV_PIX_FMT_GBRAP,
+    AV_PIX_FMT_NONE
+};
+
+static int query_formats(AVFilterContext *ctx)
+{
+    AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
+    if (!fmts_list)
+        return AVERROR(ENOMEM);
+    return ff_set_common_formats(ctx, fmts_list);
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->dst;
+    PseudoColorContext *s = ctx->priv;
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+    int depth, ret, hsub, vsub, color;
+
+    depth = desc->comp[0].depth;
+    s->max = (1 << depth) - 1;
+    s->nb_planes = av_pix_fmt_count_planes(inlink->format);
+
+    if (s->index >= s->nb_planes) {
+        av_log(ctx, AV_LOG_ERROR, "index out of allowed range\n");
+        return AVERROR(EINVAL);
+    }
+
+    if ((ret = av_image_fill_linesizes(s->linesize, inlink->format, inlink->w)) < 0)
+        return ret;
+
+    hsub = desc->log2_chroma_w;
+    vsub = desc->log2_chroma_h;
+    s->height[1] = s->height[2] = AV_CEIL_RSHIFT(inlink->h, vsub);
+    s->height[0] = s->height[3] = inlink->h;
+    s->width[1]  = s->width[2]  = AV_CEIL_RSHIFT(inlink->w, hsub);
+    s->width[0]  = s->width[3]  = inlink->w;
+
+    s->var_values[VAR_W] = inlink->w;
+    s->var_values[VAR_H] = inlink->h;
+
+    s->var_values[VAR_YMIN] = 16 * (1 << (depth - 8));
+    s->var_values[VAR_UMIN] = 16 * (1 << (depth - 8));
+    s->var_values[VAR_VMIN] = 16 * (1 << (depth - 8));
+    s->var_values[VAR_AMIN] = 0;
+    s->var_values[VAR_YMAX] = 235 * (1 << (depth - 8));
+    s->var_values[VAR_UMAX] = 240 * (1 << (depth - 8));
+    s->var_values[VAR_VMAX] = 240 * (1 << (depth - 8));
+    s->var_values[VAR_AMAX] = s->max;
+
+    for (color = 0; color < s->nb_planes; color++) {
+        double res;
+        int val;
+
+        /* create the parsed expression */
+        av_expr_free(s->comp_expr[color]);
+        s->comp_expr[color] = NULL;
+        ret = av_expr_parse(&s->comp_expr[color], s->comp_expr_str[color],
+                            var_names, NULL, NULL, NULL, NULL, 0, ctx);
+        if (ret < 0) {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Error when parsing the expression '%s' for the component %d and color %d.\n",
+                   s->comp_expr_str[color], color, color);
+            return AVERROR(EINVAL);
+        }
+
+        /* compute the lut */
+        for (val = 0; val < FF_ARRAY_ELEMS(s->lut[color]); val++) {
+            s->var_values[VAR_VAL] = val;
+
+            res = av_expr_eval(s->comp_expr[color], s->var_values, s);
+            if (isnan(res)) {
+                av_log(ctx, AV_LOG_ERROR,
+                       "Error when evaluating the expression '%s' for the value %d for the component %d.\n",
+                       s->comp_expr_str[color], val, color);
+                return AVERROR(EINVAL);
+            }
+            s->lut[color][val] = res;
+        }
+    }
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    AVFilterContext *ctx = inlink->dst;
+    PseudoColorContext *s = ctx->priv;
+    AVFilterLink *outlink = ctx->outputs[0];
+    AVFrame *out;
+    int x, y, plane;
+
+    out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+    if (!out) {
+        av_frame_free(&in);
+        return AVERROR(ENOMEM);
+    }
+    av_frame_copy_props(out, in);
+
+    for (plane = 0; plane < s->nb_planes; plane++) {
+        const uint8_t *index = in->data[s->index];
+        const uint8_t *src = in->data[plane];
+        uint8_t *dst = out->data[plane];
+
+        for (y = 0; y < s->height[plane]; y++) {
+            for (x = 0; x < s->width[plane]; x++) {
+                int v = s->lut[plane][index[x]];
+
+                if (v >= 0 && v <= s->max) {
+                    dst[x] = v;
+                } else {
+                    dst[x] = src[x];
+                }
+            }
+            index += in->linesize[s->index];
+            src += in->linesize[plane];
+            dst += out->linesize[plane];
+        }
+    }
+
+    av_frame_free(&in);
+    return ff_filter_frame(outlink, out);
+}
+
+static const AVFilterPad inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = filter_frame,
+        .config_props = config_input,
+    },
+    { NULL }
+};
+
+static const AVFilterPad outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    PseudoColorContext *s = ctx->priv;
+    int i;
+
+    for (i = 0; i < 4; i++) {
+        av_expr_free(s->comp_expr[i]);
+        s->comp_expr[i] = NULL;
+    }
+}
+
+AVFILTER_DEFINE_CLASS(pseudocolor);
+
+AVFilter ff_vf_pseudocolor = {
+    .name          = "pseudocolor",
+    .description   = NULL_IF_CONFIG_SMALL("Make pseudocolored video frames."),
+    .priv_size     = sizeof(PseudoColorContext),
+    .priv_class    = &pseudocolor_class,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .inputs        = inputs,
+    .outputs       = outputs,
+    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
+};