avfilter: add removegrain

Signed-off-by: Paul B Mahol <onemda@gmail.com>

Changelog

@@ -13,6 +13,7 @@ version <next>:
 - Many improvements to the JPEG 2000 decoder
 - Go2Meeting decoding support
 - adrawgraph audio and drawgraph video filter
+- removegrain video filter
 
 
 version 2.7:

doc/filters.texi

@@ -8005,6 +8005,110 @@ qp=2+2*sin(PI*qp)
 @end example
 @end itemize
 
+@section removegrain
+
+The removegrain filter is a spatial denoiser for progressive video.
+
+@table @option
+@item m0
+Set mode for the first plane.
+
+@item m1
+Set mode for the second plane.
+
+@item m2
+Set mode for the third plane.
+
+@item m3
+Set mode for the fourth plane.
+@end table
+
+Range of mode is from 0 to 24. Description of each mode follows:
+
+@table @var
+@item 0
+Leave input plane unchanged. Default.
+
+@item 1
+Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
+
+@item 2
+Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
+
+@item 3
+Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
+
+@item 4
+Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.
+This is equivalent to a median filter.
+
+@item 5
+Line-sensitive clipping giving the minimal change.
+
+@item 6
+Line-sensitive clipping, intermediate.
+
+@item 7
+Line-sensitive clipping, intermediate.
+
+@item 8
+Line-sensitive clipping, intermediate.
+
+@item 9
+Line-sensitive clipping on a line where the neighbours pixels are the closest.
+
+@item 10
+Replaces the target pixel with the closest neighbour.
+
+@item 11
+[1 2 1] horizontal and vertical kernel blur.
+
+@item 12
+Same as mode 11.
+
+@item 13
+Bob mode, interpolates top field from the line where the neighbours
+pixels are the closest.
+
+@item 14
+Bob mode, interpolates bottom field from the line where the neighbours
+pixels are the closest.
+
+@item 15
+Bob mode, interpolates top field. Same as 13 but with a more complicated
+interpolation formula.
+
+@item 16
+Bob mode, interpolates bottom field. Same as 14 but with a more complicated
+interpolation formula.
+
+@item 17
+Clips the pixel with the minimum and maximum of respectively the maximum and
+minimum of each pair of opposite neighbour pixels.
+
+@item 18
+Line-sensitive clipping using opposite neighbours whose greatest distance from
+the current pixel is minimal.
+
+@item 19
+Replaces the pixel with the average of its 8 neighbours.
+
+@item 20
+Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
+
+@item 21
+Clips pixels using the averages of opposite neighbour.
+
+@item 22
+Same as mode 21 but simpler and faster.
+
+@item 23
+Small edge and halo removal, but reputed useless.
+
+@item 24
+Similar as 23.
+@end table
+
 @section removelogo
 
 Suppress a TV station logo, using an image file to determine which

libavfilter/Makefile

@@ -178,6 +178,7 @@ OBJS-$(CONFIG_PP7_FILTER)                    += vf_pp7.o
 OBJS-$(CONFIG_PSNR_FILTER)                   += vf_psnr.o dualinput.o framesync.o
 OBJS-$(CONFIG_PULLUP_FILTER)                 += vf_pullup.o
 OBJS-$(CONFIG_QP_FILTER)                     += vf_qp.o
+OBJS-$(CONFIG_REMOVEGRAIN_FILTER)            += vf_removegrain.o
 OBJS-$(CONFIG_REMOVELOGO_FILTER)             += bbox.o lswsutils.o lavfutils.o vf_removelogo.o
 OBJS-$(CONFIG_REPEATFIELDS_FILTER)           += vf_repeatfields.o
 OBJS-$(CONFIG_ROTATE_FILTER)                 += vf_rotate.o

libavfilter/allfilters.c

@@ -193,6 +193,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(PSNR,           psnr,           vf);
     REGISTER_FILTER(PULLUP,         pullup,         vf);
     REGISTER_FILTER(QP,             qp,             vf);
+    REGISTER_FILTER(REMOVEGRAIN,    removegrain,    vf);
     REGISTER_FILTER(REMOVELOGO,     removelogo,     vf);
     REGISTER_FILTER(REPEATFIELDS,   repeatfields,   vf);
     REGISTER_FILTER(ROTATE,         rotate,         vf);

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  5
-#define LIBAVFILTER_VERSION_MINOR  20
+#define LIBAVFILTER_VERSION_MINOR  21
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

libavfilter/vf_removegrain.c

@@ -0,0 +1,660 @@
+/*
+ * Copyright (c) 2012 Laurent de Soras
+ * Copyright (c) 2013 Fredrik Mellbin
+ * Copyright (c) 2015 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
+ */
+
+/*
+ * TODO: add SIMD
+ */
+
+#include "libavutil/imgutils.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+typedef struct RemoveGrainContext {
+    const AVClass *class;
+
+    int mode[4];
+
+    int nb_planes;
+    int planewidth[4];
+    int planeheight[4];
+    int skip_even;
+    int skip_odd;
+
+    int (*rg[4])(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8);
+} RemoveGrainContext;
+
+#define OFFSET(x) offsetof(RemoveGrainContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+
+static const AVOption removegrain_options[] = {
+    { "m0", "set mode for 1st plane", OFFSET(mode[0]), AV_OPT_TYPE_INT, {.i64=0}, 0, 24, FLAGS },
+    { "m1", "set mode for 2nd plane", OFFSET(mode[1]), AV_OPT_TYPE_INT, {.i64=0}, 0, 24, FLAGS },
+    { "m2", "set mode for 3rd plane", OFFSET(mode[2]), AV_OPT_TYPE_INT, {.i64=0}, 0, 24, FLAGS },
+    { "m3", "set mode for 4th plane", OFFSET(mode[3]), AV_OPT_TYPE_INT, {.i64=0}, 0, 24, FLAGS },
+    {NULL}
+};
+
+AVFILTER_DEFINE_CLASS(removegrain);
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        AV_PIX_FMT_GRAY8,
+        AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV444P,
+        AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA444P,
+        AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
+        AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
+        AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P,
+        AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP,
+        AV_PIX_FMT_NONE
+    };
+
+    AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
+    if (!fmts_list)
+        return AVERROR(ENOMEM);
+    return ff_set_common_formats(ctx, fmts_list);
+}
+
+#define REMOVE_GRAIN_SORT_AXIS       \
+    const int ma1 = FFMAX(a1, a8);   \
+    const int mi1 = FFMIN(a1, a8);   \
+    const int ma2 = FFMAX(a2, a7);   \
+    const int mi2 = FFMIN(a2, a7);   \
+    const int ma3 = FFMAX(a3, a6);   \
+    const int mi3 = FFMIN(a3, a6);   \
+    const int ma4 = FFMAX(a4, a5);   \
+    const int mi4 = FFMIN(a4, a5);
+
+static int mode01(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    const int mi = FFMIN(FFMIN(FFMIN(a1, a2), FFMIN(a3, a4)), FFMIN(FFMIN(a5, a6), FFMIN(a7, a8)));
+    const int ma = FFMAX(FFMAX(FFMAX(a1, a2), FFMAX(a3, a4)), FFMAX(FFMAX(a5, a6), FFMAX(a7, a8)));
+
+    return av_clip(c, mi, ma);
+}
+
+static int cmp_int(const void *p1, const void *p2)
+{
+    int left = *(const int *)p1;
+    int right = *(const int *)p2;
+
+    return ((left > right) - (left < right));
+}
+
+static int mode02(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    int a[8] = { a1, a2, a3, a4, a5, a6, a7, a8 };
+
+    qsort(&a, 8, sizeof(a[0]), cmp_int);
+
+    return av_clip(c, a[2 - 1 ], a[7 - 1]);
+}
+
+static int mode03(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    int a[8] = { a1, a2, a3, a4, a5, a6, a7, a8 };
+
+    qsort(&a, 8, sizeof(a[0]), cmp_int);
+
+    return av_clip(c, a[3 - 1 ], a[6 - 1]);
+}
+
+static int mode04(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    int a[8] = { a1, a2, a3, a4, a5, a6, a7, a8 };
+
+    qsort(&a, 8, sizeof(a[0]), cmp_int);
+
+    return av_clip(c, a[4 - 1 ], a[5 - 1]);
+}
+
+static int mode05(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    REMOVE_GRAIN_SORT_AXIS
+
+    const int c1 = FFABS(c - av_clip(c, mi1, ma1));
+    const int c2 = FFABS(c - av_clip(c, mi2, ma2));
+    const int c3 = FFABS(c - av_clip(c, mi3, ma3));
+    const int c4 = FFABS(c - av_clip(c, mi4, ma4));
+
+    const int mindiff = FFMIN(FFMIN(c1, c2), FFMIN(c3, c4));
+
+    if (mindiff == c4) {
+        return av_clip(c, mi4, ma4);
+    } else if (mindiff == c2) {
+        return av_clip(c, mi2, ma2);
+    } else if (mindiff == c3) {
+        return av_clip(c, mi3, ma3);
+    }
+
+    return av_clip(c, mi1, ma1);
+}
+
+static int mode06(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    REMOVE_GRAIN_SORT_AXIS
+
+    const int d1 = ma1 - mi1;
+    const int d2 = ma2 - mi2;
+    const int d3 = ma3 - mi3;
+    const int d4 = ma4 - mi4;
+
+    const int cli1 = av_clip(c, mi1, ma1);
+    const int cli2 = av_clip(c, mi2, ma2);
+    const int cli3 = av_clip(c, mi3, ma3);
+    const int cli4 = av_clip(c, mi4, ma4);
+
+    const int c1 = av_clip_uint8((FFABS(c - cli1) << 1) + d1);
+    const int c2 = av_clip_uint8((FFABS(c - cli2) << 1) + d2);
+    const int c3 = av_clip_uint8((FFABS(c - cli3) << 1) + d3);
+    const int c4 = av_clip_uint8((FFABS(c - cli4) << 1) + d4);
+
+    const int mindiff = FFMIN(FFMIN(c1, c2), FFMIN(c3, c4));
+
+    if (mindiff == c4) {
+        return cli4;
+    } else if (mindiff == c2) {
+        return cli2;
+    } else if (mindiff == c3) {
+        return cli3;
+    }
+
+    return cli1;
+}
+
+static int mode07(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    REMOVE_GRAIN_SORT_AXIS
+
+    const int d1 = ma1 - mi1;
+    const int d2 = ma2 - mi2;
+    const int d3 = ma3 - mi3;
+    const int d4 = ma4 - mi4;
+
+    const int cli1 = av_clip(c, mi1, ma1);
+    const int cli2 = av_clip(c, mi2, ma2);
+    const int cli3 = av_clip(c, mi3, ma3);
+    const int cli4 = av_clip(c, mi4, ma4);
+
+    const int c1 = FFABS(c - cli1) + d1;
+    const int c2 = FFABS(c - cli2) + d2;
+    const int c3 = FFABS(c - cli3) + d3;
+    const int c4 = FFABS(c - cli4) + d4;
+
+    const int mindiff = FFMIN(FFMIN(c1, c2), FFMIN(c3, c4));
+
+    if (mindiff == c4) {
+        return cli4;
+    } else if (mindiff == c2) {
+        return cli2;
+    } else if (mindiff == c3) {
+        return cli3;
+    }
+
+    return cli1;
+}
+
+static int mode08(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    REMOVE_GRAIN_SORT_AXIS
+
+    const int d1 = ma1 - mi1;
+    const int d2 = ma2 - mi2;
+    const int d3 = ma3 - mi3;
+    const int d4 = ma4 - mi4;
+
+    const int cli1 = av_clip(c, mi1, ma1);
+    const int cli2 = av_clip(c, mi2, ma2);
+    const int cli3 = av_clip(c, mi3, ma3);
+    const int cli4 = av_clip(c, mi4, ma4);
+
+    const int c1 = av_clip_uint8(FFABS(c - cli1) + (d1 << 1));
+    const int c2 = av_clip_uint8(FFABS(c - cli2) + (d2 << 1));
+    const int c3 = av_clip_uint8(FFABS(c - cli3) + (d3 << 1));
+    const int c4 = av_clip_uint8(FFABS(c - cli4) + (d4 << 1));
+
+    const int mindiff = FFMIN(FFMIN(c1, c2), FFMIN(c3, c4));
+
+    if (mindiff == c4) {
+        return cli4;
+    } else if (mindiff == c2) {
+        return cli2;
+    } else if (mindiff == c3) {
+        return cli3;
+    }
+
+    return cli1;
+}
+
+static int mode09(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    REMOVE_GRAIN_SORT_AXIS
+
+    const int d1 = ma1 - mi1;
+    const int d2 = ma2 - mi2;
+    const int d3 = ma3 - mi3;
+    const int d4 = ma4 - mi4;
+
+    const int mindiff = FFMIN(FFMIN(d1, d2), FFMIN(d3, d4));
+
+    if (mindiff == d4) {
+        return av_clip(c, mi4, ma4);
+    } else if (mindiff == d2) {
+        return av_clip(c, mi2, ma2);
+    } else if (mindiff == d3) {
+        return av_clip(c, mi3, ma3);
+    }
+
+    return av_clip(c, mi1, ma1);
+}
+
+static int mode10(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    const int d1 = FFABS(c - a1);
+    const int d2 = FFABS(c - a2);
+    const int d3 = FFABS(c - a3);
+    const int d4 = FFABS(c - a4);
+    const int d5 = FFABS(c - a5);
+    const int d6 = FFABS(c - a6);
+    const int d7 = FFABS(c - a7);
+    const int d8 = FFABS(c - a8);
+
+    const int mindiff = FFMIN(FFMIN(FFMIN(d1, d2), FFMIN(d3, d4)),
+                              FFMIN(FFMIN(d5, d6), FFMIN(d7, d8)));
+
+    if (mindiff == d7) return a7;
+    if (mindiff == d8) return a8;
+    if (mindiff == d6) return a6;
+    if (mindiff == d2) return a2;
+    if (mindiff == d3) return a3;
+    if (mindiff == d1) return a1;
+    if (mindiff == d5) return a5;
+
+    return a4;
+}
+
+static int mode1112(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    const int sum = 4 * c + 2 * (a2 + a4 + a5 + a7) + a1 + a3 + a6 + a8;
+    const int val = (sum + 8) >> 4;
+
+    return val;
+}
+
+static int mode1314(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    const int d1 = FFABS(a1 - a8);
+    const int d2 = FFABS(a2 - a7);
+    const int d3 = FFABS(a3 - a6);
+
+    const int mindiff = FFMIN(FFMIN(d1, d2), d3);
+
+    if (mindiff == d2) {
+        return (a2 + a7 + 1) >> 1;
+    }
+    if (mindiff == d3) {
+        return (a3 + a6 + 1) >> 1;
+    }
+
+    return (a1 + a8 + 1) >> 1;
+}
+
+static int mode1516(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    const int d1 = FFABS(a1 - a8);
+    const int d2 = FFABS(a2 - a7);
+    const int d3 = FFABS(a3 - a6);
+
+    const int mindiff = FFMIN(FFMIN(d1, d2), d3);
+    const int average = (2 * (a2 + a7) + a1 + a3 + a6 + a8 + 4) >> 3;
+
+    if (mindiff == d2) {
+        return av_clip(average, FFMIN(a2, a7), FFMAX(a2, a7));
+    }
+    if (mindiff == d3) {
+        return av_clip(average, FFMIN(a3, a6), FFMAX(a3, a6));
+    }
+
+    return av_clip(average, FFMIN(a1, a8), FFMAX(a1, a8));
+}
+
+static int mode17(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    REMOVE_GRAIN_SORT_AXIS
+
+    const int l = FFMAX(FFMAX(mi1, mi2), FFMAX(mi3, mi4));
+    const int u = FFMIN(FFMIN(ma1, ma2), FFMIN(ma3, ma4));
+
+    return av_clip(c, FFMIN(l, u), FFMAX(l, u));
+}
+
+static int mode18(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    const int d1 = FFMAX(FFABS(c - a1), FFABS(c - a8));
+    const int d2 = FFMAX(FFABS(c - a2), FFABS(c - a7));
+    const int d3 = FFMAX(FFABS(c - a3), FFABS(c - a6));
+    const int d4 = FFMAX(FFABS(c - a4), FFABS(c - a5));
+
+    const int mindiff = FFMIN(FFMIN(d1, d2), FFMIN(d3, d4));
+
+    if (mindiff == d4) {
+        return av_clip(c, FFMIN(a4, a5), FFMAX(a4, a5));
+    }
+    if (mindiff == d2) {
+        return av_clip(c, FFMIN(a2, a7), FFMAX(a2, a7));
+    }
+    if (mindiff == d3) {
+        return av_clip(c, FFMIN(a3, a6), FFMAX(a3, a6));
+    }
+
+    return av_clip(c, FFMIN(a1, a8), FFMAX(a1, a8));
+}
+
+static int mode19(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    const int sum = a1 + a2 + a3 + a4 + a5 + a6 + a7 + a8;
+    const int val = (sum + 4) >> 3;
+
+    return val;
+}
+
+static int mode20(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    const int sum = a1 + a2 + a3 + a4 + c + a5 + a6 + a7 + a8;
+    const int val = (sum + 4) / 9;
+
+    return val;
+}
+
+static int mode21(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    const int l1l = (a1 + a8) >> 1;
+    const int l2l = (a2 + a7) >> 1;
+    const int l3l = (a3 + a6) >> 1;
+    const int l4l = (a4 + a5) >> 1;
+
+    const int l1h = (a1 + a8 + 1) >> 1;
+    const int l2h = (a2 + a7 + 1) >> 1;
+    const int l3h = (a3 + a6 + 1) >> 1;
+    const int l4h = (a4 + a5 + 1) >> 1;
+
+    const int mi = FFMIN(FFMIN(l1l, l2l), FFMIN(l3l, l4l));
+    const int ma = FFMAX(FFMAX(l1h, l2h), FFMAX(l3h, l4h));
+
+    return av_clip(c, mi, ma);
+}
+
+static int mode22(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    const int l1 = (a1 + a8 + 1) >> 1;
+    const int l2 = (a2 + a7 + 1) >> 1;
+    const int l3 = (a3 + a6 + 1) >> 1;
+    const int l4 = (a4 + a5 + 1) >> 1;
+
+    const int mi = FFMIN(FFMIN(l1, l2), FFMIN(l3, l4));
+    const int ma = FFMAX(FFMAX(l1, l2), FFMAX(l3, l4));
+
+    return av_clip(c, mi, ma);
+}
+
+static int mode23(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    REMOVE_GRAIN_SORT_AXIS
+
+    const int linediff1 = ma1 - mi1;
+    const int linediff2 = ma2 - mi2;
+    const int linediff3 = ma3 - mi3;
+    const int linediff4 = ma4 - mi4;
+
+    const int u1 = FFMIN(c - ma1, linediff1);
+    const int u2 = FFMIN(c - ma2, linediff2);
+    const int u3 = FFMIN(c - ma3, linediff3);
+    const int u4 = FFMIN(c - ma4, linediff4);
+    const int u = FFMAX(FFMAX(FFMAX(u1, u2), FFMAX(u3, u4)), 0);
+
+    const int d1 = FFMIN(mi1 - c, linediff1);
+    const int d2 = FFMIN(mi2 - c, linediff2);
+    const int d3 = FFMIN(mi3 - c, linediff3);
+    const int d4 = FFMIN(mi4 - c, linediff4);
+    const int d = FFMAX(FFMAX(FFMAX(d1, d2), FFMAX(d3, d4)), 0);
+
+    return c - u + d;  // This probably will never overflow.
+}
+
+static int mode24(int c, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8)
+{
+    REMOVE_GRAIN_SORT_AXIS
+
+    const int linediff1 = ma1 - mi1;
+    const int linediff2 = ma2 - mi2;
+    const int linediff3 = ma3 - mi3;
+    const int linediff4 = ma4 - mi4;
+
+    const int tu1 = c - ma1;
+    const int tu2 = c - ma2;
+    const int tu3 = c - ma3;
+    const int tu4 = c - ma4;
+
+    const int u1 = FFMIN(tu1, linediff1 - tu1);
+    const int u2 = FFMIN(tu2, linediff2 - tu2);
+    const int u3 = FFMIN(tu3, linediff3 - tu3);
+    const int u4 = FFMIN(tu4, linediff4 - tu4);
+    const int u = FFMAX(FFMAX(FFMAX(u1, u2), FFMAX(u3, u4)), 0);
+
+    const int td1 = mi1 - c;
+    const int td2 = mi2 - c;
+    const int td3 = mi3 - c;
+    const int td4 = mi4 - c;
+
+    const int d1 = FFMIN(td1, linediff1 - td1);
+    const int d2 = FFMIN(td2, linediff2 - td2);
+    const int d3 = FFMIN(td3, linediff3 - td3);
+    const int d4 = FFMIN(td4, linediff4 - td4);
+    const int d = FFMAX(FFMAX(FFMAX(d1, d2), FFMAX(d3, d4)), 0);
+
+    return c - u + d;  // This probably will never overflow.
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    RemoveGrainContext *s = inlink->dst->priv;
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+    int i;
+
+    s->nb_planes = av_pix_fmt_count_planes(inlink->format);
+
+    s->planeheight[1] = s->planeheight[2] = FF_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
+    s->planeheight[0] = s->planeheight[3] = inlink->h;
+    s->planewidth[1]  = s->planewidth[2]  = FF_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
+    s->planewidth[0]  = s->planewidth[3]  = inlink->w;
+
+    for (i = 0; i < s->nb_planes; i++) {
+        switch (s->mode[i]) {
+        case 1:  s->rg[i] = mode01;   break;
+        case 2:  s->rg[i] = mode02;   break;
+        case 3:  s->rg[i] = mode03;   break;
+        case 4:  s->rg[i] = mode04;   break;
+        case 5:  s->rg[i] = mode05;   break;
+        case 6:  s->rg[i] = mode06;   break;
+        case 7:  s->rg[i] = mode07;   break;
+        case 8:  s->rg[i] = mode08;   break;
+        case 9:  s->rg[i] = mode09;   break;
+        case 10: s->rg[i] = mode10;   break;
+        case 11: s->rg[i] = mode1112; break;
+        case 12: s->rg[i] = mode1112; break;
+        case 13: s->skip_odd = 1;
+                 s->rg[i] = mode1314; break;
+        case 14: s->skip_even = 1;
+                 s->rg[i] = mode1314; break;
+        case 15: s->skip_odd = 1;
+                 s->rg[i] = mode1516; break;
+        case 16: s->skip_even = 1;
+                 s->rg[i] = mode1516; break;
+        case 17: s->rg[i] = mode17;   break;
+        case 18: s->rg[i] = mode18;   break;
+        case 19: s->rg[i] = mode19;   break;
+        case 20: s->rg[i] = mode20;   break;
+        case 21: s->rg[i] = mode21;   break;
+        case 22: s->rg[i] = mode22;   break;
+        case 23: s->rg[i] = mode23;   break;
+        case 24: s->rg[i] = mode24;   break;
+        }
+    }
+
+    return 0;
+}
+
+typedef struct ThreadData {
+    AVFrame *in, *out;
+    int plane;
+} ThreadData;
+
+static int filter_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
+{
+    RemoveGrainContext *s = ctx->priv;
+    ThreadData *td = arg;
+    AVFrame *in = td->in;
+    AVFrame *out = td->out;
+    const int i = td->plane;
+    const int height = s->planeheight[i];
+    const int om = in->linesize[i] - 1;
+    const int o0 = in->linesize[i]    ;
+    const int op = in->linesize[i] + 1;
+    int start = (height *  jobnr   ) / nb_jobs;
+    int end   = (height * (jobnr+1)) / nb_jobs;
+    int x, y;
+
+    start = FFMAX(1, start);
+    end   = FFMIN(height-1, end);
+    for (y = start; y < end; y++) {
+        uint8_t *dst = out->data[i];
+        uint8_t *src = in->data[i];
+
+        src = in->data[i] + y * in->linesize[i];
+        dst = out->data[i] + y * out->linesize[i];
+
+        if (s->skip_even && !(y & 1)) {
+            memcpy(dst, src, s->planewidth[i]);
+            continue;
+        }
+        if (s->skip_odd && y & 1) {
+            memcpy(dst, src, s->planewidth[i]);
+            continue;
+        }
+
+        *dst++ = *src++;
+        for (x = 1; x < s->planewidth[i] - 1; x++) {
+            const int a1 = src[-op];
+            const int a2 = src[-o0];
+            const int a3 = src[-om];
+            const int a4 = src[-1 ];
+            const int c  = src[ 0 ];
+            const int a5 = src[ 1 ];
+            const int a6 = src[ om];
+            const int a7 = src[ o0];
+            const int a8 = src[ op];
+
+            const int res = s->rg[i](c, a1, a2, a3, a4, a5, a6, a7, a8);
+
+            *dst = res;
+            dst++, src++;
+        }
+        dst[0] = src[0];
+    }
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    RemoveGrainContext *s = ctx->priv;
+    ThreadData td;
+    AVFrame *out;
+    int i;
+
+    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 (i = 0; i < s->nb_planes; i++) {
+        uint8_t *dst = out->data[i];
+        uint8_t *src = in->data[i];
+
+        if (s->mode[i] == 0) {
+            av_image_copy_plane(dst, out->linesize[i],
+                                src, in->linesize[i],
+                                s->planewidth[i], s->planeheight[i]);
+            continue;
+        }
+
+        memcpy(dst, src, s->planewidth[i]);
+
+        td.in = in; td.out = out; td.plane = i;
+        ctx->internal->execute(ctx, filter_slice, &td, NULL,
+                               FFMIN(s->planeheight[i], ctx->graph->nb_threads));
+
+        src = in->data[i] + (s->planeheight[i] - 1) * in->linesize[i];
+        dst = out->data[i] + (s->planeheight[i] - 1) * out->linesize[i];
+        memcpy(dst, src, s->planewidth[i]);
+    }
+
+    av_frame_free(&in);
+    return ff_filter_frame(outlink, out);
+}
+
+static const AVFilterPad removegrain_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = filter_frame,
+        .config_props = config_input,
+    },
+    { NULL }
+};
+
+static const AVFilterPad removegrain_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_removegrain = {
+    .name          = "removegrain",
+    .description   = NULL_IF_CONFIG_SMALL("Remove grain."),
+    .priv_size     = sizeof(RemoveGrainContext),
+    .query_formats = query_formats,
+    .inputs        = removegrain_inputs,
+    .outputs       = removegrain_outputs,
+    .priv_class    = &removegrain_class,
+    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
+};