Add unsharp video filter.

Contributed by Daniel G. Taylor (dan/at/programmer-art/dot/org)

Originally committed as revision 22813 to svn://svn.ffmpeg.org/ffmpeg/trunk

doc/libavfilter.texi

@@ -217,6 +217,59 @@ not specified it will use the default value of 16.
 Adding this in the beginning of filter chains should make filtering
 faster due to better use of the memory cache.
 
+@section unsharp
+
+Sharpen or blur the input video. It accepts the following parameters:
+
+@multitable @columnfractions .2 .5 .1 .1 .1
+@headitem Name @tab Description @tab Min @tab Max @tab Default
+@item @var{luma_msize_x}
+@tab Luma matrix horizontal size
+@tab 3
+@tab 13
+@tab 5
+@item @var{luma_msize_y}
+@tab Luma matrix vertical size
+@tab 3
+@tab 13
+@tab 5
+@item @var{luma_amount}
+@tab Luma effect strength
+@tab -2.0
+@tab 5.0
+@tab 1.0
+@item @var{chroma_msize_x}
+@tab Chroma matrix horizontal size
+@tab 3
+@tab 13
+@tab 0
+@item @var{chroma_msize_y}
+@tab Chroma matrix vertical size
+@tab 3
+@tab 13
+@tab 0
+@item @var{chroma_amount}
+@tab Chroma effect strength
+@tab -2.0
+@tab 5.0
+@tab 0.0
+@end multitable
+
+Negative values for the amount will blur the input video, while positive
+values will sharpen. All parameters are optional and default to the
+equivalent of the string '5:5:1.0:0:0:0.0'.
+
+@example
+# Strong luma sharpen effect parameters
+unsharp=7:7:2.5
+
+# Strong blur of both luma and chroma parameters
+unsharp=7:7:-2:7:7:-2
+
+# Use the default values with @command{ffmpeg}
+./ffmpeg -i in.avi -vfilters "unsharp" out.mp4
+@end example
+
 @section vflip
 
 Flip the input video vertically.

libavfilter/Makefile

@@ -22,6 +22,7 @@ OBJS-$(CONFIG_NULL_FILTER)                   += vf_null.o
 OBJS-$(CONFIG_PIXELASPECT_FILTER)            += vf_aspect.o
 OBJS-$(CONFIG_SCALE_FILTER)                  += vf_scale.o
 OBJS-$(CONFIG_SLICIFY_FILTER)                += vf_slicify.o
+OBJS-$(CONFIG_UNSHARP_FILTER)                += vf_unsharp.o
 OBJS-$(CONFIG_VFLIP_FILTER)                  += vf_vflip.o
 
 OBJS-$(CONFIG_NULLSRC_FILTER)                += vsrc_nullsrc.o

libavfilter/allfilters.c

@@ -42,6 +42,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (PIXELASPECT, pixelaspect, vf);
     REGISTER_FILTER (SCALE,       scale,       vf);
     REGISTER_FILTER (SLICIFY,     slicify,     vf);
+    REGISTER_FILTER (UNSHARP,     unsharp,     vf);
     REGISTER_FILTER (VFLIP,       vflip,       vf);
 
     REGISTER_FILTER (NULLSRC,     nullsrc,     vsrc);

libavfilter/vf_unsharp.c

@@ -0,0 +1,236 @@
+/*
+ * Ported to FFmpeg from MPlayer libmpcodecs/unsharp.c
+ * Original copyright (C) 2002 Remi Guyomarch <rguyom@pobox.com>
+ * Port copyright (C) 2010 Daniel G. Taylor <dan@programmer-art.org>
+ * Relicensed to the LGPL with permission from Remi Guyomarch.
+ *
+ * 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 libavfilter/vf_unsharp.c
+ * blur / sharpen filter
+ *
+ * This code is based on:
+ *
+ * An Efficient algorithm for Gaussian blur using finite-state machines
+ * Frederick M. Waltz and John W. V. Miller
+ *
+ * SPIE Conf. on Machine Vision Systems for Inspection and Metrology VII
+ * Originally published Boston, Nov 98
+ *
+ * http://www.engin.umd.umich.edu/~jwvm/ece581/21_GBlur.pdf
+ */
+
+#include "avfilter.h"
+#include "libavutil/common.h"
+#include "libavutil/mem.h"
+#include "libavutil/pixdesc.h"
+
+#define MIN_SIZE 3
+#define MAX_SIZE 13
+
+#define CHROMA_WIDTH(link)  -((-link->w) >> av_pix_fmt_descriptors[link->format].log2_chroma_w)
+#define CHROMA_HEIGHT(link) -((-link->h) >> av_pix_fmt_descriptors[link->format].log2_chroma_h)
+
+typedef struct FilterParam {
+    int msize_x;                             ///< matrix width
+    int msize_y;                             ///< matrix height
+    int amount;                              ///< effect amount
+    int steps_x;                             ///< horizontal step count
+    int steps_y;                             ///< vertical step count
+    int scalebits;                           ///< bits to shift pixel
+    int32_t halfscale;                       ///< amount to add to pixel
+    uint32_t *sc[(MAX_SIZE * MAX_SIZE) - 1]; ///< finite state machine storage
+} FilterParam;
+
+typedef struct {
+    FilterParam luma;   ///< luma parameters (width, height, amount)
+    FilterParam chroma; ///< chroma parameters (width, height, amount)
+} UnsharpContext;
+
+static void unsharpen(uint8_t *dst, uint8_t *src, int dst_stride, int src_stride, int width, int height, FilterParam *fp)
+{
+    uint32_t **sc = fp->sc;
+    uint32_t sr[(MAX_SIZE * MAX_SIZE) - 1], tmp1, tmp2;
+
+    int32_t res;
+    int x, y, z;
+
+    if (!fp->amount) {
+        if (dst_stride == src_stride)
+            memcpy(dst, src, src_stride * height);
+        else
+            for (y = 0; y < height; y++, dst += dst_stride, src += src_stride)
+                memcpy(dst, src, width);
+        return;
+    }
+
+    for (y = 0; y < 2 * fp->steps_y; y++)
+        memset(sc[y], 0, sizeof(sc[y][0]) * (width + 2 * fp->steps_x));
+
+    for (y =- fp->steps_y; y < height + fp->steps_y; y++) {
+        memset(sr, 0, sizeof(sr[0]) * (2 * fp->steps_x - 1));
+        for (x =- fp->steps_x; x < width + fp->steps_x; x++) {
+            tmp1 = x <= 0 ? src[0] : x >= width ? src[width-1] : src[x];
+            for (z = 0; z < fp->steps_x * 2; z += 2) {
+                tmp2 = sr[z + 0] + tmp1; sr[z + 0] = tmp1;
+                tmp1 = sr[z + 1] + tmp2; sr[z + 1] = tmp2;
+            }
+            for (z = 0; z < fp->steps_y * 2; z += 2) {
+                tmp2 = sc[z + 0][x + fp->steps_x] + tmp1; sc[z + 0][x + fp->steps_x] = tmp1;
+                tmp1 = sc[z + 1][x + fp->steps_x] + tmp2; sc[z + 1][x + fp->steps_x] = tmp2;
+            }
+            if (x >= fp->steps_x && y >= fp->steps_y) {
+                uint8_t* srx = src - fp->steps_y * src_stride + x - fp->steps_x;
+                uint8_t* dsx = dst - fp->steps_y * dst_stride + x - fp->steps_x;
+
+                res = (int32_t)*srx + ((((int32_t) * srx - (int32_t)((tmp1 + fp->halfscale) >> fp->scalebits)) * fp->amount) >> 16);
+                *dsx = av_clip_uint8(res);
+            }
+        }
+        if (y >= 0) {
+            dst += dst_stride;
+            src += src_stride;
+        }
+    }
+}
+
+static void set_filter_param(FilterParam *fp, int msize_x, int msize_y, double amount)
+{
+    fp->msize_x = msize_x;
+    fp->msize_y = msize_y;
+    fp->amount = amount * 65536.0;
+
+    fp->steps_x = msize_x / 2;
+    fp->steps_y = msize_y / 2;
+    fp->scalebits = (fp->steps_x + fp->steps_y) * 2;
+    fp->halfscale = 1 << (fp->scalebits - 1);
+}
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    UnsharpContext *unsharp = ctx->priv;
+    int lmsize_x = 5, cmsize_x = 0;
+    int lmsize_y = 5, cmsize_y = 0;
+    double lamount = 1.0f, camount = 0.0f;
+
+    if (args)
+        sscanf(args, "%d:%d:%lf:%d:%d:%lf", &lmsize_x, &lmsize_y, &lamount,
+                                            &cmsize_x, &cmsize_y, &camount);
+
+    set_filter_param(&unsharp->luma,   lmsize_x, lmsize_y, lamount);
+    set_filter_param(&unsharp->chroma, cmsize_x, cmsize_y, camount);
+
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    enum PixelFormat pix_fmts[] = {
+        PIX_FMT_YUV420P,  PIX_FMT_YUV422P,  PIX_FMT_YUV444P,  PIX_FMT_YUV410P,
+        PIX_FMT_YUV411P,  PIX_FMT_YUV440P,  PIX_FMT_YUVJ420P, PIX_FMT_YUVJ422P,
+        PIX_FMT_YUVJ444P, PIX_FMT_YUVJ440P, PIX_FMT_NONE
+    };
+
+    avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
+
+    return 0;
+}
+
+static void init_filter_param(AVFilterContext *ctx, FilterParam *fp, const char *effect_type, int width)
+{
+    int z;
+    const char *effect;
+
+    effect = fp->amount == 0 ? "none" : fp->amount < 0 ? "blur" : "sharpen";
+
+    av_log(ctx, AV_LOG_INFO, "effect:%s type:%s msize_x:%d msize_y:%d amount:%0.2f\n",
+           effect, effect_type, fp->msize_x, fp->msize_y, fp->amount / 65535.0);
+
+    for (z = 0; z < 2 * fp->steps_y; z++)
+        fp->sc[z] = av_malloc(sizeof(*(fp->sc[z])) * (width + 2 * fp->steps_x));
+}
+
+static int config_props(AVFilterLink *link)
+{
+    UnsharpContext *unsharp = link->dst->priv;
+
+    init_filter_param(link->dst, &unsharp->luma,   "luma",   link->w);
+    init_filter_param(link->dst, &unsharp->chroma, "chroma", CHROMA_WIDTH(link));
+
+    return 0;
+}
+
+static void free_filter_param(FilterParam *fp)
+{
+    int z;
+
+    for (z = 0; z < 2 * fp->steps_y; z++)
+        av_free(fp->sc[z]);
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    UnsharpContext *unsharp = ctx->priv;
+
+    free_filter_param(&unsharp->luma);
+    free_filter_param(&unsharp->chroma);
+}
+
+static void end_frame(AVFilterLink *link)
+{
+    UnsharpContext *unsharp = link->dst->priv;
+    AVFilterPicRef *in  = link->cur_pic;
+    AVFilterPicRef *out = link->dst->outputs[0]->outpic;
+
+    unsharpen(out->data[0], in->data[0], out->linesize[0], in->linesize[0], link->w,            link->h,             &unsharp->luma);
+    unsharpen(out->data[1], in->data[1], out->linesize[1], in->linesize[1], CHROMA_WIDTH(link), CHROMA_HEIGHT(link), &unsharp->chroma);
+    unsharpen(out->data[2], in->data[2], out->linesize[2], in->linesize[2], CHROMA_WIDTH(link), CHROMA_HEIGHT(link), &unsharp->chroma);
+
+    avfilter_unref_pic(in);
+    avfilter_draw_slice(link->dst->outputs[0], 0, link->h, 1);
+    avfilter_end_frame(link->dst->outputs[0]);
+    avfilter_unref_pic(out);
+}
+
+static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
+{
+}
+
+AVFilter avfilter_vf_unsharp = {
+    .name      = "unsharp",
+    .description = NULL_IF_CONFIG_SMALL("Sharpen or blur the input video."),
+
+    .priv_size = sizeof(UnsharpContext),
+
+    .init = init,
+    .uninit = uninit,
+    .query_formats = query_formats,
+
+    .inputs    = (AVFilterPad[]) {{ .name             = "default",
+                                    .type             = AVMEDIA_TYPE_VIDEO,
+                                    .draw_slice       = draw_slice,
+                                    .end_frame        = end_frame,
+                                    .config_props     = config_props,
+                                    .min_perms        = AV_PERM_READ, },
+                                  { .name = NULL}},
+
+    .outputs   = (AVFilterPad[]) {{ .name             = "default",
+                                    .type             = AVMEDIA_TYPE_VIDEO, },
+                                  { .name = NULL}},
+};