avfilter: add convolution filter

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

Changelog

@@ -57,6 +57,7 @@ version <next>:
 - only seek with the right mouse button in ffplay
 - toggle full screen when double-clicking with the left mouse button in ffplay
 - afftfilt filter
+- convolution filter
 
 
 version 2.8:

doc/filters.texi

@@ -4662,6 +4662,68 @@ For example to convert from BT.601 to SMPTE-240M, use the command:
 colormatrix=bt601:smpte240m
 @end example
 
+@section convolution
+
+Apply convolution 3x3 or 5x5 filter.
+
+The filter accepts the following options:
+
+@table @option
+@item 0m
+@item 1m
+@item 2m
+@item 3m
+Set matrix for each plane.
+Matrix is sequence of 9 or 25 signed integers.
+
+@item 0rdiv
+@item 1rdiv
+@item 2rdiv
+@item 3rdiv
+Set multiplier for calculated value for each plane.
+
+@item 0bias
+@item 1bias
+@item 2bias
+@item 3bias
+Set bias for each plane. This value is added to the result of the multiplication.
+Useful for making the overall image brighter or darker. Default is 0.0.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Apply sharpen:
+@example
+convolution="0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0"
+@end example
+
+@item
+Apply blur:
+@example
+convolution="1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1/9:1/9:1/9:1/9"
+@end example
+
+@item
+Apply edge enhance:
+@example
+convolution="0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:5:1:1:1:0:128:128:128"
+@end example
+
+@item
+Apply edge detect:
+@example
+convolution="0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:5:5:5:1:0:128:128:128"
+@end example
+
+@item
+Apply emboss:
+@example
+convolution="-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2"
+@end example
+@end itemize
+
 @section copy
 
 Copy the input source unchanged to the output. This is mainly useful for

libavfilter/Makefile

@@ -123,6 +123,7 @@ OBJS-$(CONFIG_COLORCHANNELMIXER_FILTER)      += vf_colorchannelmixer.o
 OBJS-$(CONFIG_COLORKEY_FILTER)               += vf_colorkey.o
 OBJS-$(CONFIG_COLORLEVELS_FILTER)            += vf_colorlevels.o
 OBJS-$(CONFIG_COLORMATRIX_FILTER)            += vf_colormatrix.o
+OBJS-$(CONFIG_CONVOLUTION_FILTER)            += vf_convolution.o
 OBJS-$(CONFIG_COPY_FILTER)                   += vf_copy.o
 OBJS-$(CONFIG_COVER_RECT_FILTER)             += vf_cover_rect.o lavfutils.o
 OBJS-$(CONFIG_CROP_FILTER)                   += vf_crop.o

libavfilter/allfilters.c

@@ -144,6 +144,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(COLORKEY,       colorkey,       vf);
     REGISTER_FILTER(COLORLEVELS,    colorlevels,    vf);
     REGISTER_FILTER(COLORMATRIX,    colormatrix,    vf);
+    REGISTER_FILTER(CONVOLUTION,    convolution,    vf);
     REGISTER_FILTER(COPY,           copy,           vf);
     REGISTER_FILTER(COVER_RECT,     cover_rect,     vf);
     REGISTER_FILTER(CROP,           crop,           vf);

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR  26
+#define LIBAVFILTER_VERSION_MINOR  27
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

libavfilter/vf_convolution.c

+/*
+ * Copyright (c) 2012-2013 Oka Motofumi (chikuzen.mo at gmail dot com)
+ * 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
+ */
+
+#include "libavutil/avstring.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"
+
+typedef struct ConvolutionContext {
+    const AVClass *class;
+
+    char *matrix_str[4];
+    float rdiv[4];
+    float bias[4];
+
+    int bstride;
+    uint8_t *buffer;
+    int nb_planes;
+    int planewidth[4];
+    int planeheight[4];
+    int matrix[4][25];
+    int matrix_length[4];
+    int copy[4];
+
+    void (*filter[4])(struct ConvolutionContext *s, AVFrame *in, AVFrame *out, int plane);
+} ConvolutionContext;
+
+#define OFFSET(x) offsetof(ConvolutionContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption convolution_options[] = {
+    { "0m", "set matrix for 1st plane", OFFSET(matrix_str[0]), AV_OPT_TYPE_STRING, {.str="0 0 0 0 1 0 0 0 0"}, 0, 0, FLAGS },
+    { "1m", "set matrix for 2nd plane", OFFSET(matrix_str[1]), AV_OPT_TYPE_STRING, {.str="0 0 0 0 1 0 0 0 0"}, 0, 0, FLAGS },
+    { "2m", "set matrix for 3rd plane", OFFSET(matrix_str[2]), AV_OPT_TYPE_STRING, {.str="0 0 0 0 1 0 0 0 0"}, 0, 0, FLAGS },
+    { "3m", "set matrix for 4th plane", OFFSET(matrix_str[3]), AV_OPT_TYPE_STRING, {.str="0 0 0 0 1 0 0 0 0"}, 0, 0, FLAGS },
+    { "0rdiv", "set rdiv for 1st plane", OFFSET(rdiv[0]), AV_OPT_TYPE_FLOAT, {.dbl=1.0}, 0.0, INT_MAX, FLAGS},
+    { "1rdiv", "set rdiv for 2nd plane", OFFSET(rdiv[1]), AV_OPT_TYPE_FLOAT, {.dbl=1.0}, 0.0, INT_MAX, FLAGS},
+    { "2rdiv", "set rdiv for 3rd plane", OFFSET(rdiv[2]), AV_OPT_TYPE_FLOAT, {.dbl=1.0}, 0.0, INT_MAX, FLAGS},
+    { "3rdiv", "set rdiv for 4th plane", OFFSET(rdiv[3]), AV_OPT_TYPE_FLOAT, {.dbl=1.0}, 0.0, INT_MAX, FLAGS},
+    { "0bias", "set bias for 1st plane", OFFSET(bias[0]), AV_OPT_TYPE_FLOAT, {.dbl=0.0}, 0.0, INT_MAX, FLAGS},
+    { "1bias", "set bias for 2nd plane", OFFSET(bias[1]), AV_OPT_TYPE_FLOAT, {.dbl=0.0}, 0.0, INT_MAX, FLAGS},
+    { "2bias", "set bias for 3rd plane", OFFSET(bias[2]), AV_OPT_TYPE_FLOAT, {.dbl=0.0}, 0.0, INT_MAX, FLAGS},
+    { "3bias", "set bias for 4th plane", OFFSET(bias[3]), AV_OPT_TYPE_FLOAT, {.dbl=0.0}, 0.0, INT_MAX, FLAGS},
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(convolution);
+
+static const int same3x3[9] = {0, 0, 0,
+                               0, 1, 0,
+                               0, 0, 0};
+
+static const int same5x5[25] = {0, 0, 0, 0, 0,
+                                0, 0, 0, 0, 0,
+                                0, 0, 1, 0, 0,
+                                0, 0, 0, 0, 0,
+                                0, 0, 0, 0, 0};
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P,
+        AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV411P,
+        AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
+        AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ411P,
+        AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV440P,
+        AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP,
+        AV_PIX_FMT_GRAY8,
+        AV_PIX_FMT_NONE
+    };
+
+    return ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    ConvolutionContext *s = inlink->dst->priv;
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+    int ret;
+
+    if ((ret = av_image_fill_linesizes(s->planewidth, inlink->format, inlink->w)) < 0)
+        return ret;
+
+    s->planeheight[1] = s->planeheight[2] = FF_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
+    s->planeheight[0] = s->planeheight[3] = inlink->h;
+
+    s->nb_planes = av_pix_fmt_count_planes(inlink->format);
+
+    s->bstride = s->planewidth[0] + 32;
+    s->buffer = av_malloc(5 * s->bstride);
+    if (!s->buffer)
+        return AVERROR(ENOMEM);
+
+    return 0;
+}
+
+static inline void line_copy8(uint8_t *line, const uint8_t *srcp, int width, int mergin)
+{
+    int i;
+
+    memcpy(line, srcp, width);
+
+    for (i = mergin; i > 0; i--) {
+        line[-i] = line[i];
+        line[width - 1 + i] = line[width - 1 - i];
+    }
+}
+
+static void filter_3x3(ConvolutionContext *s, AVFrame *in, AVFrame *out, int plane)
+{
+    const uint8_t *src = in->data[plane];
+    uint8_t *dst = out->data[plane];
+    const int stride = in->linesize[plane];
+    const int bstride = s->bstride;
+    const int height = s->planeheight[plane];
+    const int width  = s->planewidth[plane];
+    uint8_t *p0 = s->buffer + 16;
+    uint8_t *p1 = p0 + bstride;
+    uint8_t *p2 = p1 + bstride;
+    uint8_t *orig = p0, *end = p2;
+    const int *matrix = s->matrix[plane];
+    const float rdiv = s->rdiv[plane];
+    const float bias = s->bias[plane];
+    int y, x;
+
+    line_copy8(p0, src + stride, width, 1);
+    line_copy8(p1, src, width, 1);
+
+    for (y = 0; y < height; y++) {
+        src += stride * (y < height - 1 ? 1 : -1);
+        line_copy8(p2, src, width, 1);
+
+        for (x = 0; x < width; x++) {
+            int sum = p0[x - 1] * matrix[0] +
+                      p0[x] *     matrix[1] +
+                      p0[x + 1] * matrix[2] +
+                      p1[x - 1] * matrix[3] +
+                      p1[x] *     matrix[4] +
+                      p1[x + 1] * matrix[5] +
+                      p2[x - 1] * matrix[6] +
+                      p2[x] *     matrix[7] +
+                      p2[x + 1] * matrix[8];
+            sum = (int)(sum * rdiv + bias + 0.5f);
+            dst[x] = av_clip(sum, 0, 255);
+        }
+
+        p0 = p1;
+        p1 = p2;
+        p2 = (p2 == end) ? orig: p2 + bstride;
+        dst += out->linesize[plane];
+    }
+}
+
+static void filter_5x5(ConvolutionContext *s, AVFrame *in, AVFrame *out, int plane)
+{
+    const uint8_t *src = in->data[plane];
+    uint8_t *dst = out->data[plane];
+    const int stride = in->linesize[plane];
+    const int bstride = s->bstride;
+    const int height = s->planeheight[plane];
+    const int width  = s->planewidth[plane];
+    uint8_t *p0 = s->buffer + 16;
+    uint8_t *p1 = p0 + bstride;
+    uint8_t *p2 = p1 + bstride;
+    uint8_t *p3 = p2 + bstride;
+    uint8_t *p4 = p3 + bstride;
+    uint8_t *orig = p0, *end = p4;
+    const int *matrix = s->matrix[plane];
+    float rdiv = s->rdiv[plane];
+    float bias = s->bias[plane];
+    int y, x, i;
+
+    line_copy8(p0, src + 2 * stride, width, 2);
+    line_copy8(p1, src + stride, width, 2);
+    line_copy8(p2, src, width, 2);
+    src += stride;
+    line_copy8(p3, src, width, 2);
+
+
+    for (y = 0; y < height; y++) {
+        uint8_t *array[] = {
+            p0 - 2, p0 - 1, p0, p0 + 1, p0 + 2,
+            p1 - 2, p1 - 1, p1, p1 + 1, p1 + 2,
+            p2 - 2, p2 - 1, p2, p2 + 1, p2 + 2,
+            p3 - 2, p3 - 1, p3, p3 + 1, p3 + 2,
+            p4 - 2, p4 - 1, p4, p4 + 1, p4 + 2
+        };
+
+        src += stride * (y < height - 2 ? 1 : -1);
+        line_copy8(p4, src, width, 2);
+
+        for (x = 0; x < width; x++) {
+            int sum = 0;
+
+            for (i = 0; i < 25; i++) {
+                sum += *(array[i] + x) * matrix[i];
+            }
+            sum = (int)(sum * rdiv + bias + 0.5f);
+            dst[x] = av_clip(sum, 0, 255);
+        }
+
+        p0 = p1;
+        p1 = p2;
+        p2 = p3;
+        p3 = p4;
+        p4 = (p4 == end) ? orig: p4 + bstride;
+        dst += out->linesize[plane];
+    }
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    ConvolutionContext *s = inlink->dst->priv;
+    AVFilterLink *outlink = inlink->dst->outputs[0];
+    AVFrame *out;
+    int 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++) {
+        if (s->copy[plane]) {
+            av_image_copy_plane(out->data[plane], out->linesize[plane],
+                                in->data[plane], in->linesize[plane],
+                                s->planewidth[plane],
+                                s->planeheight[plane]);
+            continue;
+        }
+
+        s->filter[plane](s, in, out, plane);
+    }
+
+    av_frame_free(&in);
+    return ff_filter_frame(outlink, out);
+}
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    ConvolutionContext *s = ctx->priv;
+    int i;
+
+    for (i = 0; i < 4; i++) {
+        int *matrix = (int *)s->matrix[i];
+        char *p, *arg, *saveptr = NULL;
+
+        p = s->matrix_str[i];
+        while (s->matrix_length[i] < 25) {
+            if (!(arg = av_strtok(p, " ", &saveptr)))
+                break;
+
+            p = NULL;
+            sscanf(arg, "%d", &matrix[s->matrix_length[i]]);
+            s->matrix_length[i]++;
+        }
+
+        if (s->matrix_length[i] == 9) {
+            if (!memcmp(matrix, same3x3, sizeof(same3x3)))
+                s->copy[i] = 1;
+            else
+                s->filter[i] = filter_3x3;
+        } else if (s->matrix_length[i] == 25) {
+            if (!memcmp(matrix, same5x5, sizeof(same5x5)))
+                s->copy[i] = 1;
+            else
+                s->filter[i] = filter_5x5;
+        } else {
+            return AVERROR(EINVAL);
+        }
+    }
+
+    return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    ConvolutionContext *s = ctx->priv;
+
+    av_freep(&s->buffer);
+}
+
+static const AVFilterPad convolution_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .config_props = config_input,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad convolution_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_convolution = {
+    .name          = "convolution",
+    .description   = NULL_IF_CONFIG_SMALL("Apply convolution filter."),
+    .priv_size     = sizeof(ConvolutionContext),
+    .priv_class    = &convolution_class,
+    .init          = init,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .inputs        = convolution_inputs,
+    .outputs       = convolution_outputs,
+};