lavfi: add nlmeans filter

Fixes Ticket #4910

Changelog

@@ -31,6 +31,7 @@ version <next>:
 - MediaCodec HEVC decoding
 - TrueHD encoder
 - Meridian Lossless Packing (MLP) encoder
+- Non-Local Means (nlmeans) denoising filter
 
 
 version 3.1:

doc/filters.texi

@@ -9695,6 +9695,41 @@ Negate input video.
 It accepts an integer in input; if non-zero it negates the
 alpha component (if available). The default value in input is 0.
 
+@section nlmeans
+
+Denoise frames using Non-Local Means algorithm.
+
+Each pixel is adjusted by looking for other pixels with similar contexts. This
+context similarity is defined by comparing their surrounding patches of size
+@option{p}x@option{p}. Patches are searched in an area of @option{r}x@option{r}
+around the pixel.
+
+Note that the research area defines centers for patches, which means some
+patches will be made of pixels outside that research area.
+
+The filter accepts the following options.
+
+@table @option
+@item s
+Set denoising strength.
+
+@item p
+Set patch size.
+
+@item pc
+Same as @option{p} but for chroma planes.
+
+The default value is @var{0} and means automatic.
+
+@item r
+Set research size.
+
+@item rc
+Same as @option{r} but for chroma planes.
+
+The default value is @var{0} and means automatic.
+@end table
+
 @section nnedi
 
 Deinterlace video using neural network edge directed interpolation.

libavfilter/Makefile

@@ -220,6 +220,7 @@ OBJS-$(CONFIG_METADATA_FILTER)               += f_metadata.o
 OBJS-$(CONFIG_MINTERPOLATE_FILTER)           += vf_minterpolate.o motion_estimation.o
 OBJS-$(CONFIG_MPDECIMATE_FILTER)             += vf_mpdecimate.o
 OBJS-$(CONFIG_NEGATE_FILTER)                 += vf_lut.o
+OBJS-$(CONFIG_NLMEANS_FILTER)                += vf_nlmeans.o
 OBJS-$(CONFIG_NNEDI_FILTER)                  += vf_nnedi.o
 OBJS-$(CONFIG_NOFORMAT_FILTER)               += vf_format.o
 OBJS-$(CONFIG_NOISE_FILTER)                  += vf_noise.o
@@ -354,7 +355,7 @@ SKIPHEADERS-$(CONFIG_OPENCL)                 += opencl_internal.h deshake_opencl
 OBJS-$(CONFIG_SHARED)                        += log2_tab.o
 
 TOOLS     = graph2dot
-TESTPROGS = drawutils filtfmts formats
+TESTPROGS = drawutils filtfmts formats integral
 
 TOOLS-$(CONFIG_LIBZMQ) += zmqsend
 

libavfilter/allfilters.c

@@ -237,6 +237,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(MINTERPOLATE,   minterpolate,   vf);
     REGISTER_FILTER(MPDECIMATE,     mpdecimate,     vf);
     REGISTER_FILTER(NEGATE,         negate,         vf);
+    REGISTER_FILTER(NLMEANS,        nlmeans,        vf);
     REGISTER_FILTER(NNEDI,          nnedi,          vf);
     REGISTER_FILTER(NOFORMAT,       noformat,       vf);
     REGISTER_FILTER(NOISE,          noise,          vf);

libavfilter/tests/integral.c

+/*
+ * 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 "libavfilter/vf_nlmeans.c"
+
+static void display_integral(const uint32_t *ii, int w, int h, int lz_32)
+{
+    int x, y;
+
+    for (y = 0; y < h; y++) {
+        for (x = 0; x < w; x++)
+            printf(" %7x", ii[y*lz_32 + x]);
+        printf("\n");
+    }
+    printf("---------------\n");
+}
+
+int main(void)
+{
+    int ret = 0, xoff, yoff;
+
+    // arbitrary test source of size 6x4 and linesize=8
+    const int w = 6, h = 5, lz = 8;
+    static const uint8_t src[] = {
+        0xb0, 0x71, 0xfb, 0xd8, 0x01, 0xd9, /***/ 0x01, 0x02,
+        0x51, 0x8e, 0x41, 0x0f, 0x84, 0x58, /***/ 0x03, 0x04,
+        0xc7, 0x8d, 0x07, 0x70, 0x5c, 0x47, /***/ 0x05, 0x06,
+        0x09, 0x4e, 0xfc, 0x74, 0x8f, 0x9a, /***/ 0x07, 0x08,
+        0x60, 0x8e, 0x20, 0xaa, 0x95, 0x7d, /***/ 0x09, 0x0a,
+    };
+
+    const int e = 3;
+    const int ii_w = w+e*2, ii_h = h+e*2;
+
+    // align to 4 the linesize, "+1" is for the space of the left 0-column
+    const int ii_lz_32 = ((ii_w + 1) + 3) & ~3;
+
+    // "+1" is for the space of the top 0-line
+    uint32_t *ii  = av_mallocz_array(ii_h + 1, ii_lz_32 * sizeof(*ii));
+    uint32_t *ii2 = av_mallocz_array(ii_h + 1, ii_lz_32 * sizeof(*ii2));
+
+    uint32_t *ii_start  = ii  + ii_lz_32 + 1; // skip top 0-line and left 0-column
+    uint32_t *ii_start2 = ii2 + ii_lz_32 + 1; // skip top 0-line and left 0-column
+
+    if (!ii || !ii2)
+        return -1;
+
+    for (yoff = -e; yoff <= e; yoff++) {
+        for (xoff = -e; xoff <= e; xoff++) {
+            int x, y;
+
+            printf("xoff=%d yoff=%d\n", xoff, yoff);
+
+            compute_ssd_integral_image(ii_start, ii_lz_32,
+                                       src, lz, xoff, yoff, e, w, h);
+            display_integral(ii_start, ii_w, ii_h, ii_lz_32);
+
+            compute_unsafe_ssd_integral_image(ii_start2, ii_lz_32,
+                                              0, 0,
+                                              src, lz,
+                                              xoff, yoff, e, w, h,
+                                              ii_w, ii_h);
+            display_integral(ii_start2, ii_w, ii_h, ii_lz_32);
+
+            if (memcmp(ii, ii2, (ii_h+1) * ii_lz_32 * sizeof(*ii))) {
+                printf("Integral mismatch\n");
+                ret = 1;
+                goto end;
+            }
+        }
+    }
+
+end:
+    av_freep(&ii);
+    av_freep(&ii2);
+    return ret;
+}

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR  62
+#define LIBAVFILTER_VERSION_MINOR  63
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \