lavfi: add geq filter.

Changelog

@@ -22,6 +22,7 @@ version <next>:
 - metadata (info chunk) support in CAF muxer
 - field filter ported from libmpcodecs
 - AVR demuxer
+- geq filter ported from libmpcodecs
 
 
 version 1.0:

LICENSE

@@ -30,6 +30,7 @@ Specifically, the GPL parts of FFmpeg are
     - vf_cropdetect.c
     - vf_decimate.c
     - vf_delogo.c
+    - vf_geq.c
     - vf_hqdn3d.c
     - vf_hue.c
     - vf_mp.c

configure

@@ -1939,6 +1939,7 @@ frei0r_filter_deps="frei0r dlopen"
 frei0r_filter_extralibs='$ldl'
 frei0r_src_filter_deps="frei0r dlopen"
 frei0r_src_filter_extralibs='$ldl'
+geq_filter_deps="gpl"
 hqdn3d_filter_deps="gpl"
 hue_filter_deps="gpl"
 movie_filter_deps="avcodec avformat"

doc/filters.texi

@@ -2364,6 +2364,81 @@ frei0r=perspective:0.2/0.2:0.8/0.2
 For more information see:
 @url{http://frei0r.dyne.org}
 
+@section geq
+
+The filter takes one, two or three equations as parameter, separated by ':'.
+The first equation is mandatory and applies to the luma plane. The two
+following are respectively for chroma blue and chroma red planes.
+
+The filter syntax allows named parameters:
+
+@table @option
+@item lum_expr
+the luminance expression
+@item cb_expr
+the chrominance blue expression
+@item cr_expr
+the chrominance red expression
+@end table
+
+If one of the chrominance expression is not defined, it falls back on the other
+one. If none of them are specified, they will evaluate the luminance
+expression.
+
+The expressions can use the following variables and functions:
+
+@table @option
+@item N
+The sequential number of the filtered frame, starting from @code{0}.
+
+@item X, Y
+The coordinates of the current sample.
+
+@item W, H
+The width and height of the image.
+
+@item SW, SH
+Width and height scale depending on the currently filtered plane. It is the
+ratio between the corresponding luma plane number of pixels and the current
+plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
+@code{0.5,0.5} for chroma planes.
+
+@item p(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the current
+plane.
+
+@item lum(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the luminance
+plane.
+
+@item cb(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the
+blue-difference chroma plane.
+
+@item cr(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the
+red-difference chroma plane.
+@end table
+
+For functions, if @var{x} and @var{y} are outside the area, the value will be
+automatically clipped to the closer edge.
+
+Some examples follow:
+
+@itemize
+@item
+Flip the image horizontally:
+@example
+geq=p(W-X\,Y)
+@end example
+
+@item
+Generate a fancy enigmatic moving light:
+@example
+nullsrc=s=256x256,geq=random(1)/hypot(X-cos(N*0.07)*W/2-W/2\,Y-sin(N*0.09)*H/2-H/2)^2*1000000*sin(N*0.02):128:128
+@end example
+@end itemize
+
 @section gradfun
 
 Fix the banding artifacts that are sometimes introduced into nearly flat
@@ -4469,9 +4544,9 @@ color=c=red@@0.2:s=qcif:r=10
 
 If the input content is to be ignored, @code{nullsrc} can be used. The
 following command generates noise in the luminance plane by employing
-the @code{mp=geq} filter:
+the @code{geq} filter:
 @example
-nullsrc=s=256x256, mp=geq=random(1)*255:128:128
+nullsrc=s=256x256, geq=random(1)*255:128:128
 @end example
 
 @c man end VIDEO SOURCES

libavfilter/Makefile

@@ -105,6 +105,7 @@ OBJS-$(CONFIG_FORMAT_FILTER)                 += vf_format.o
 OBJS-$(CONFIG_FRAMESTEP_FILTER)              += vf_framestep.o
 OBJS-$(CONFIG_FPS_FILTER)                    += vf_fps.o
 OBJS-$(CONFIG_FREI0R_FILTER)                 += vf_frei0r.o
+OBJS-$(CONFIG_GEQ_FILTER)                    += vf_geq.o
 OBJS-$(CONFIG_GRADFUN_FILTER)                += vf_gradfun.o
 OBJS-$(CONFIG_HFLIP_FILTER)                  += vf_hflip.o
 OBJS-$(CONFIG_HQDN3D_FILTER)                 += vf_hqdn3d.o

libavfilter/allfilters.c

@@ -97,6 +97,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (FPS,         fps,         vf);
     REGISTER_FILTER (FRAMESTEP,   framestep,   vf);
     REGISTER_FILTER (FREI0R,      frei0r,      vf);
+    REGISTER_FILTER (GEQ,         geq,         vf);
     REGISTER_FILTER (GRADFUN,     gradfun,     vf);
     REGISTER_FILTER (HFLIP,       hflip,       vf);
     REGISTER_FILTER (HQDN3D,      hqdn3d,      vf);

libavfilter/version.h

@@ -29,8 +29,8 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  3
-#define LIBAVFILTER_VERSION_MINOR  21
-#define LIBAVFILTER_VERSION_MICRO 108
+#define LIBAVFILTER_VERSION_MINOR  22
+#define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \

libavfilter/vf_geq.c

+/*
+ * Copyright (C) 2006 Michael Niedermayer <michaelni@gmx.at>
+ * Copyright (C) 2012 Clément Bœsch <ubitux@gmail.com>
+ *
+ * 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
+ * Generic equation change filter
+ * Originally written by Michael Niedermayer for the MPlayer project, and
+ * ported by Clément Bœsch for FFmpeg.
+ */
+
+#include "libavutil/avstring.h"
+#include "libavutil/eval.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+#include "internal.h"
+
+typedef struct {
+    const AVClass *class;
+    AVExpr *e[3];               ///< expressions for each plane
+    char *expr_str[3];          ///< expression strings for each plane
+    int framenum;               ///< frame counter
+    AVFilterBufferRef *picref;  ///< current input buffer
+    int hsub, vsub;             ///< chroma subsampling
+} GEQContext;
+
+#define OFFSET(x) offsetof(GEQContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption geq_options[] = {
+    { "lum_expr",   "set luminance expression",   OFFSET(expr_str),                   AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
+    { "cb_expr",    "set chroma blue expression", OFFSET(expr_str) +   sizeof(char*), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
+    { "cr_expr",    "set chroma red expression",  OFFSET(expr_str) + 2*sizeof(char*), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
+    {NULL},
+};
+
+AVFILTER_DEFINE_CLASS(geq);
+
+static inline double getpix(void *priv, double x, double y, int plane)
+{
+    int xi, yi;
+    GEQContext *geq = priv;
+    AVFilterBufferRef *picref = geq->picref;
+    const uint8_t *src = picref->data[plane];
+    const int linesize = picref->linesize[plane];
+    const int w = picref->video->w >> (plane ? geq->hsub : 0);
+    const int h = picref->video->h >> (plane ? geq->vsub : 0);
+
+    xi = x = av_clipf(x, 0, w - 2);
+    yi = y = av_clipf(y, 0, h - 2);
+
+    x -= xi;
+    y -= yi;
+
+    return (1-y)*((1-x)*src[xi +  yi    * linesize] + x*src[xi + 1 +  yi    * linesize])
+          +   y *((1-x)*src[xi + (yi+1) * linesize] + x*src[xi + 1 + (yi+1) * linesize]);
+}
+
+//TODO: cubic interpolate
+//TODO: keep the last few frames
+static double lum(void *priv, double x, double y) { return getpix(priv, x, y, 0); }
+static double  cb(void *priv, double x, double y) { return getpix(priv, x, y, 1); }
+static double  cr(void *priv, double x, double y) { return getpix(priv, x, y, 2); }
+
+static const char *const var_names[] = {   "X",   "Y",   "W",   "H",   "N",   "SW",   "SH",        NULL };
+enum                                   { VAR_X, VAR_Y, VAR_W, VAR_H, VAR_N, VAR_SW, VAR_SH, VAR_VARS_NB };
+
+static av_cold int geq_init(AVFilterContext *ctx, const char *args)
+{
+    GEQContext *geq = ctx->priv;
+    int plane, ret = 0;
+    static const char *shorthand[] = { "lum_expr", "cb_expr", "cr_expr", NULL };
+
+    geq->class = &geq_class;
+    av_opt_set_defaults(geq);
+
+    if ((ret = av_opt_set_from_string(geq, args, shorthand, "=", ":")) < 0)
+        return ret;
+
+    if (!geq->expr_str[0]) {
+        av_log(ctx, AV_LOG_ERROR, "Luminance expression is mandatory\n");
+        ret = AVERROR(EINVAL);
+        goto end;
+    }
+
+    if (!geq->expr_str[1] && !geq->expr_str[2]) {
+        /* No chroma at all: fallback on luma */
+        geq->expr_str[1] = av_strdup(geq->expr_str[0]);
+        geq->expr_str[2] = av_strdup(geq->expr_str[0]);
+    } else {
+        /* One chroma unspecified, fallback on the other */
+        if (!geq->expr_str[1]) geq->expr_str[1] = av_strdup(geq->expr_str[2]);
+        if (!geq->expr_str[2]) geq->expr_str[2] = av_strdup(geq->expr_str[1]);
+    }
+
+    if (!geq->expr_str[1] || !geq->expr_str[2]) {
+        ret = AVERROR(ENOMEM);
+        goto end;
+    }
+
+    for (plane = 0; plane < 3; plane++) {
+        static double (*p[])(void *, double, double) = { lum, cb, cr };
+        static const char *const func2_names[]    = { "lum", "cb", "cr", "p", NULL };
+        double (*func2[])(void *, double, double) = { lum, cb, cr, p[plane], NULL };
+
+        ret = av_expr_parse(&geq->e[plane], geq->expr_str[plane], var_names,
+                            NULL, NULL, func2_names, func2, 0, ctx);
+        if (ret < 0)
+            break;
+    }
+
+end:
+    return ret;
+}
+
+static int geq_query_formats(AVFilterContext *ctx)
+{
+    static const enum PixelFormat pix_fmts[] = {
+        AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV422P,  AV_PIX_FMT_YUV420P,
+        AV_PIX_FMT_YUV411P,  AV_PIX_FMT_YUV410P,  AV_PIX_FMT_YUV440P,
+        AV_PIX_FMT_YUVA420P,
+        AV_PIX_FMT_NONE
+    };
+    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
+    return 0;
+}
+
+static int geq_config_props(AVFilterLink *inlink)
+{
+    GEQContext *geq = inlink->dst->priv;
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+
+    geq->hsub = desc->log2_chroma_w;
+    geq->vsub = desc->log2_chroma_h;
+    return 0;
+}
+
+static int geq_end_frame(AVFilterLink *inlink)
+{
+    int ret, plane;
+    GEQContext *geq = inlink->dst->priv;
+    AVFilterLink *outlink = inlink->dst->outputs[0];
+    AVFilterBufferRef *outpicref = outlink->out_buf;
+    double values[VAR_VARS_NB] = {
+        [VAR_N] = geq->framenum++,
+    };
+
+    geq->picref = inlink->cur_buf;
+
+    for (plane = 0; plane < 3; plane++) {
+        int x, y;
+        uint8_t *dst = outpicref->data[plane];
+        const int linesize = outpicref->linesize[plane];
+        const int w = inlink->w >> (plane ? geq->hsub : 0);
+        const int h = inlink->h >> (plane ? geq->vsub : 0);
+
+        values[VAR_W]  = w;
+        values[VAR_H]  = h;
+        values[VAR_SW] = w / (double)inlink->w;
+        values[VAR_SH] = h / (double)inlink->h;
+
+        for (y = 0; y < h; y++) {
+            values[VAR_Y] = y;
+            for (x = 0; x < w; x++) {
+                values[VAR_X] = x;
+                dst[x] = av_expr_eval(geq->e[plane], values, geq);
+            }
+            dst += linesize;
+        }
+    }
+
+    if ((ret = ff_draw_slice(outlink, 0, outlink->h, 1)) < 0 ||
+        (ret = ff_end_frame(outlink)) < 0)
+        return ret;
+    return 0;
+}
+
+static av_cold void geq_uninit(AVFilterContext *ctx)
+{
+    int i;
+    GEQContext *geq = ctx->priv;
+
+    for (i = 0; i < FF_ARRAY_ELEMS(geq->e); i++)
+        av_expr_free(geq->e[i]);
+    av_opt_free(geq);
+}
+
+static int null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir) { return 0; }
+
+static const AVFilterPad geq_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .draw_slice   = null_draw_slice,
+        .config_props = geq_config_props,
+        .end_frame    = geq_end_frame,
+        .min_perms    = AV_PERM_READ,
+    },
+    { NULL }
+};
+
+static const AVFilterPad geq_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+AVFilter avfilter_vf_geq = {
+    .name          = "geq",
+    .description   = NULL_IF_CONFIG_SMALL("Apply generic equation to each pixel."),
+    .priv_size     = sizeof(GEQContext),
+    .init          = geq_init,
+    .uninit        = geq_uninit,
+    .query_formats = geq_query_formats,
+    .inputs        = geq_inputs,
+    .outputs       = geq_outputs,
+    .priv_class    = &geq_class,
+};