@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
@end table
+@section lut, lutrgb, lutyuv
+
+Compute a look-up table for binding each pixel component input value
+to an output value, and apply it to input video.
+
+@var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
+to an RGB input video.
+
+These filters accept in input a ":"-separated list of options, which
+specify the expressions used for computing the lookup table for the
+corresponding pixel component values.
+
+The @var{lut} filter requires either YUV or RGB pixel formats in
+input, and accepts the options:
+@table @option
+@var{c0} (first pixel component)
+@var{c1} (second pixel component)
+@var{c2} (third pixel component)
+@var{c3} (fourth pixel component, corresponds to the alpha component)
+@end table
+
+The exact component associated to each option depends on the format in
+input.
+
+The @var{lutrgb} filter requires RGB pixel formats in input, and
+accepts the options:
+@table @option
+@var{r} (red component)
+@var{g} (green component)
+@var{b} (blue component)
+@var{a} (alpha component)
+@end table
+
+The @var{lutyuv} filter requires YUV pixel formats in input, and
+accepts the options:
+@table @option
+@var{y} (Y/luminance component)
+@var{u} (U/Cb component)
+@var{v} (V/Cr component)
+@var{a} (alpha component)
+@end table
+
+The expressions can contain the following constants and functions:
+
+@table @option
+@item E, PI, PHI
+the corresponding mathematical approximated values for e
+(euler number), pi (greek PI), PHI (golden ratio)
+
+@item w, h
+the input width and heigth
+
+@item val
+input value for the pixel component
+
+@item clipval
+the input value clipped in the @var{minval}-@var{maxval} range
+
+@item maxval
+maximum value for the pixel component
+
+@item minval
+minimum value for the pixel component
+
+@item negval
+the negated value for the pixel component value clipped in the
+@var{minval}-@var{maxval} range , it corresponds to the expression
+"maxval-clipval+minval"
+
+@item clip(val)
+the computed value in @var{val} clipped in the
+@var{minval}-@var{maxval} range
+
+@item gammaval(gamma)
+the computed gamma correction value of the pixel component value
+clipped in the @var{minval}-@var{maxval} range, corresponds to the
+expression
+"pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
+
+@end table
+
+All expressions default to "val".
+
+Some examples follow:
+@example
+# negate input video
+lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
+lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
+
+# the above is the same as
+lutrgb="r=negval:g=negval:b=negval"
+lutyuv="y=negval:u=negval:v=negval"
+
+# negate luminance
+lutyuv=negval
+
+# remove chroma components, turns the video into a graytone image
+lutyuv="u=128:v=128"
+
+# apply a luma burning effect
+lutyuv="y=2*val"
+
+# remove green and blue components
+lutrgb="g=0:b=0"
+
+# set a constant alpha channel value on input
+format=rgba,lutrgb=a="maxval-minval/2"
+
+# correct luminance gamma by a 0.5 factor
+lutyuv=y=gammaval(0.5)
+@end example
+
@section mp
Apply an MPlayer filter to the input video.
--- /dev/null
+/*
+ * Copyright (c) 2011 Stefano Sabatini
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * Compute a look-up table for binding the input value to the output
+ * value, and apply it to input video.
+ */
+
+#include "libavutil/eval.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+#include "avfilter.h"
+
+static const char *var_names[] = {
+ "E",
+ "PHI",
+ "PI",
+ "w", ///< width of the input video
+ "h", ///< height of the input video
+ "val", ///< input value for the pixel
+ "maxval", ///< max value for the pixel
+ "minval", ///< min value for the pixel
+ "negval", ///< negated value
+ "clipval",
+ NULL
+};
+
+enum var_name {
+ VAR_E,
+ VAR_PHI,
+ VAR_PI,
+ VAR_W,
+ VAR_H,
+ VAR_VAL,
+ VAR_MAXVAL,
+ VAR_MINVAL,
+ VAR_NEGVAL,
+ VAR_CLIPVAL,
+ VAR_VARS_NB
+};
+
+typedef struct {
+ const AVClass *class;
+ uint8_t lut[4][256]; ///< lookup table for each component
+ char *comp_expr_str[4];
+ AVExpr *comp_expr[4];
+ int hsub, vsub;
+ double var_values[VAR_VARS_NB];
+ int is_rgb, is_yuv;
+ int rgba_map[4];
+ int step;
+} LutContext;
+
+#define Y 0
+#define U 1
+#define V 2
+#define R 0
+#define G 1
+#define B 2
+#define A 3
+
+#define OFFSET(x) offsetof(LutContext, x)
+
+static const AVOption lut_options[] = {
+ {"c0", "set component #0 expression", OFFSET(comp_expr_str[0]), FF_OPT_TYPE_STRING, {.str="val"}, CHAR_MIN, CHAR_MAX},
+ {"c1", "set component #1 expression", OFFSET(comp_expr_str[1]), FF_OPT_TYPE_STRING, {.str="val"}, CHAR_MIN, CHAR_MAX},
+ {"c2", "set component #2 expression", OFFSET(comp_expr_str[2]), FF_OPT_TYPE_STRING, {.str="val"}, CHAR_MIN, CHAR_MAX},
+ {"c3", "set component #3 expression", OFFSET(comp_expr_str[3]), FF_OPT_TYPE_STRING, {.str="val"}, CHAR_MIN, CHAR_MAX},
+ {"y", "set Y expression", OFFSET(comp_expr_str[Y]), FF_OPT_TYPE_STRING, {.str="val"}, CHAR_MIN, CHAR_MAX},
+ {"u", "set U expression", OFFSET(comp_expr_str[U]), FF_OPT_TYPE_STRING, {.str="val"}, CHAR_MIN, CHAR_MAX},
+ {"v", "set V expression", OFFSET(comp_expr_str[V]), FF_OPT_TYPE_STRING, {.str="val"}, CHAR_MIN, CHAR_MAX},
+ {"r", "set R expression", OFFSET(comp_expr_str[R]), FF_OPT_TYPE_STRING, {.str="val"}, CHAR_MIN, CHAR_MAX},
+ {"g", "set G expression", OFFSET(comp_expr_str[G]), FF_OPT_TYPE_STRING, {.str="val"}, CHAR_MIN, CHAR_MAX},
+ {"b", "set B expression", OFFSET(comp_expr_str[B]), FF_OPT_TYPE_STRING, {.str="val"}, CHAR_MIN, CHAR_MAX},
+ {"a", "set A expression", OFFSET(comp_expr_str[A]), FF_OPT_TYPE_STRING, {.str="val"}, CHAR_MIN, CHAR_MAX},
+ {NULL},
+};
+
+static const char *lut_get_name(void *ctx)
+{
+ return "lut";
+}
+
+static const AVClass lut_class = {
+ "LutContext",
+ lut_get_name,
+ lut_options
+};
+
+static int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+ LutContext *lut = ctx->priv;
+ int ret;
+
+ lut->class = &lut_class;
+ av_opt_set_defaults2(lut, 0, 0);
+
+ lut->var_values[VAR_PHI] = M_PHI;
+ lut->var_values[VAR_PI] = M_PI;
+ lut->var_values[VAR_E ] = M_E;
+
+ lut->is_rgb = !strcmp(ctx->filter->name, "lutrgb");
+ lut->is_yuv = !strcmp(ctx->filter->name, "lutyuv");
+ if (args && (ret = av_set_options_string(lut, args, "=", ":")) < 0)
+ return ret;
+
+ return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+ LutContext *lut = ctx->priv;
+ int i;
+
+ for (i = 0; i < 4; i++) {
+ av_expr_free(lut->comp_expr[i]);
+ lut->comp_expr[i] = NULL;
+ av_freep(&lut->comp_expr_str[i]);
+ }
+}
+
+#define YUV_FORMATS \
+ PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV420P, \
+ PIX_FMT_YUV411P, PIX_FMT_YUV410P, PIX_FMT_YUV440P, \
+ PIX_FMT_YUVA420P, \
+ PIX_FMT_YUVJ444P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ420P, \
+ PIX_FMT_YUVJ440P
+
+#define RGB_FORMATS \
+ PIX_FMT_ARGB, PIX_FMT_RGBA, \
+ PIX_FMT_ABGR, PIX_FMT_BGRA, \
+ PIX_FMT_RGB24, PIX_FMT_BGR24
+
+static enum PixelFormat yuv_pix_fmts[] = { YUV_FORMATS, PIX_FMT_NONE };
+static enum PixelFormat rgb_pix_fmts[] = { RGB_FORMATS, PIX_FMT_NONE };
+static enum PixelFormat all_pix_fmts[] = { RGB_FORMATS, YUV_FORMATS, PIX_FMT_NONE };
+
+static int query_formats(AVFilterContext *ctx)
+{
+ LutContext *lut = ctx->priv;
+
+ enum PixelFormat *pix_fmts = lut->is_rgb ? rgb_pix_fmts :
+ lut->is_yuv ? yuv_pix_fmts : all_pix_fmts;
+
+ avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
+ return 0;
+}
+
+static int pix_fmt_is_in(enum PixelFormat pix_fmt, enum PixelFormat *pix_fmts)
+{
+ enum PixelFormat *p;
+ for (p = pix_fmts; *p != PIX_FMT_NONE; p++) {
+ if (pix_fmt == *p)
+ return 1;
+ }
+ return 0;
+}
+
+/**
+ * Clip value val in the minval - maxval range.
+ */
+static double clip(void *opaque, double val)
+{
+ LutContext *lut = opaque;
+ double minval = lut->var_values[VAR_MINVAL];
+ double maxval = lut->var_values[VAR_MAXVAL];
+
+ return av_clip(val, minval, maxval);
+}
+
+/**
+ * Compute gamma correction for value val, assuming the minval-maxval
+ * range, val is clipped to a value contained in the same interval.
+ */
+static double compute_gammaval(void *opaque, double gamma)
+{
+ LutContext *lut = opaque;
+ double val = lut->var_values[VAR_CLIPVAL];
+ double minval = lut->var_values[VAR_MINVAL];
+ double maxval = lut->var_values[VAR_MAXVAL];
+
+ return pow((val-minval)/(maxval-minval), gamma) * (maxval-minval)+minval;
+}
+
+static double (* const funcs1[])(void *, double) = {
+ (void *)clip,
+ (void *)compute_gammaval,
+ NULL
+};
+
+static const char * const funcs1_names[] = {
+ "clip",
+ "gammaval",
+ NULL
+};
+
+static int config_props(AVFilterLink *inlink)
+{
+ AVFilterContext *ctx = inlink->dst;
+ LutContext *lut = ctx->priv;
+ const AVPixFmtDescriptor *desc = &av_pix_fmt_descriptors[inlink->format];
+ int min[4], max[4];
+ int val, comp, ret;
+
+ lut->hsub = desc->log2_chroma_w;
+ lut->vsub = desc->log2_chroma_h;
+
+ lut->var_values[VAR_W] = inlink->w;
+ lut->var_values[VAR_H] = inlink->h;
+
+ switch (inlink->format) {
+ case PIX_FMT_YUV410P:
+ case PIX_FMT_YUV411P:
+ case PIX_FMT_YUV420P:
+ case PIX_FMT_YUV422P:
+ case PIX_FMT_YUV440P:
+ case PIX_FMT_YUV444P:
+ case PIX_FMT_YUVA420P:
+ min[Y] = min[U] = min[V] = 16;
+ max[Y] = 235;
+ max[U] = max[V] = 240;
+ break;
+ default:
+ min[0] = min[1] = min[2] = min[3] = 0;
+ max[0] = max[1] = max[2] = max[3] = 255;
+ }
+
+ lut->is_yuv = lut->is_rgb = 0;
+ if (pix_fmt_is_in(inlink->format, yuv_pix_fmts)) lut->is_yuv = 1;
+ else if (pix_fmt_is_in(inlink->format, rgb_pix_fmts)) lut->is_rgb = 1;
+
+ if (lut->is_rgb) {
+ switch (inlink->format) {
+ case PIX_FMT_ARGB: lut->rgba_map[A] = 0; lut->rgba_map[R] = 1; lut->rgba_map[G] = 2; lut->rgba_map[B] = 3; break;
+ case PIX_FMT_ABGR: lut->rgba_map[A] = 0; lut->rgba_map[B] = 1; lut->rgba_map[G] = 2; lut->rgba_map[R] = 3; break;
+ case PIX_FMT_RGBA:
+ case PIX_FMT_RGB24: lut->rgba_map[R] = 0; lut->rgba_map[G] = 1; lut->rgba_map[B] = 2; lut->rgba_map[A] = 3; break;
+ case PIX_FMT_BGRA:
+ case PIX_FMT_BGR24: lut->rgba_map[B] = 0; lut->rgba_map[G] = 1; lut->rgba_map[R] = 2; lut->rgba_map[A] = 3; break;
+ }
+ lut->step = av_get_bits_per_pixel(desc) >> 3;
+ }
+
+ for (comp = 0; comp < desc->nb_components; comp++) {
+ double res;
+
+ /* create the parsed expression */
+ ret = av_expr_parse(&lut->comp_expr[comp], lut->comp_expr_str[comp],
+ var_names, funcs1_names, funcs1, NULL, NULL, 0, ctx);
+ if (ret < 0) {
+ av_log(ctx, AV_LOG_ERROR,
+ "Error when parsing the expression '%s' for the component %d.\n",
+ lut->comp_expr_str[comp], comp);
+ return AVERROR(EINVAL);
+ }
+
+ /* compute the lut */
+ lut->var_values[VAR_MAXVAL] = max[comp];
+ lut->var_values[VAR_MINVAL] = min[comp];
+
+ for (val = 0; val < 256; val++) {
+ lut->var_values[VAR_VAL] = val;
+ lut->var_values[VAR_CLIPVAL] = av_clip(val, min[comp], max[comp]);
+ lut->var_values[VAR_NEGVAL] =
+ av_clip(min[comp] + max[comp] - lut->var_values[VAR_VAL],
+ min[comp], max[comp]);
+
+ res = av_expr_eval(lut->comp_expr[comp], lut->var_values, lut);
+ if (isnan(res)) {
+ av_log(ctx, AV_LOG_ERROR,
+ "Error when evaluating the expression '%s' for the value %d for the component #%d.\n",
+ lut->comp_expr_str[comp], val, comp);
+ return AVERROR(EINVAL);
+ }
+ lut->lut[comp][val] = av_clip((int)res, min[comp], max[comp]);
+ av_log(ctx, AV_LOG_DEBUG, "val[%d][%d] = %d\n", comp, val, lut->lut[comp][val]);
+ }
+ }
+
+ return 0;
+}
+
+static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
+{
+ AVFilterContext *ctx = inlink->dst;
+ LutContext *lut = ctx->priv;
+ AVFilterLink *outlink = ctx->outputs[0];
+ AVFilterBufferRef *inpic = inlink ->cur_buf;
+ AVFilterBufferRef *outpic = outlink->out_buf;
+ uint8_t *inrow, *outrow;
+ int i, j, k, plane;
+
+ if (lut->is_rgb) {
+ /* packed */
+ inrow = inpic ->data[0] + y * inpic ->linesize[0];
+ outrow = outpic->data[0] + y * outpic->linesize[0];
+
+ for (i = 0; i < h; i ++) {
+ for (j = 0; j < inlink->w; j++) {
+ for (k = 0; k < lut->step; k++)
+ outrow[k] = lut->lut[lut->rgba_map[k]][inrow[k]];
+ outrow += lut->step;
+ inrow += lut->step;
+ }
+ }
+ } else {
+ /* planar */
+ for (plane = 0; inpic->data[plane]; plane++) {
+ int vsub = plane == 1 || plane == 2 ? lut->vsub : 0;
+ int hsub = plane == 1 || plane == 2 ? lut->hsub : 0;
+
+ inrow = inpic ->data[plane] + (y>>vsub) * inpic ->linesize[plane];
+ outrow = outpic->data[plane] + (y>>vsub) * outpic->linesize[plane];
+
+ for (i = 0; i < h>>vsub; i ++) {
+ for (j = 0; j < inlink->w>>hsub; j++)
+ outrow[j] = lut->lut[plane][inrow[j]];
+ inrow += inpic ->linesize[plane];
+ outrow += outpic->linesize[plane];
+ }
+ }
+ }
+
+ avfilter_draw_slice(outlink, y, h, slice_dir);
+}
+
+#define DEFINE_LUT_FILTER(name_, description_, init_) \
+ AVFilter avfilter_vf_##name_ = { \
+ .name = NULL_IF_CONFIG_SMALL(#name_), \
+ .description = description_, \
+ .priv_size = sizeof(LutContext), \
+ \
+ .init = init_, \
+ .uninit = uninit, \
+ .query_formats = query_formats, \
+ \
+ .inputs = (AVFilterPad[]) {{ .name = "default", \
+ .type = AVMEDIA_TYPE_VIDEO, \
+ .draw_slice = draw_slice, \
+ .config_props = config_props, \
+ .min_perms = AV_PERM_READ, }, \
+ { .name = NULL}}, \
+ .outputs = (AVFilterPad[]) {{ .name = "default", \
+ .type = AVMEDIA_TYPE_VIDEO, }, \
+ { .name = NULL}}, \
+ }
+
+DEFINE_LUT_FILTER(lut, "Compute and apply a lookup table to the RGB/YUV input video.", init);
+DEFINE_LUT_FILTER(lutyuv, "Compute and apply a lookup table to the YUV input video.", init);
+DEFINE_LUT_FILTER(lutrgb, "Compute and apply a lookup table to the RGB input video.", init);