lavfi: add smartblur filter

This is a port of the MPlayer smartblur filter (libmpcodecs/vf_smartblur.c)
by Michael Niedermayer.
Signed-off-by: Stefano Sabatini <stefasab@gmail.com>

Changelog

@@ -54,6 +54,7 @@ version next:
 - Ut Video encoder
 - Matroska demuxer now identifies SRT subtitles as AV_CODEC_ID_SUBRIP
   instead of AV_CODEC_ID_TEXT
+- smartblur filter ported from MPlayer
 
 
 version 0.11:

configure

@@ -1867,6 +1867,7 @@ ocv_filter_deps="libopencv"
 pan_filter_deps="swresample"
 removelogo_filter_deps="avcodec avformat swscale"
 scale_filter_deps="swscale"
+smartblur_filter_deps="gpl swscale"
 select_filter_deps="avcodec"
 showspectrum_filter_deps="avcodec"
 super2xsai_filter_deps="gpl"

doc/filters.texi

@@ -3253,6 +3253,35 @@ 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 smartblur
+
+Blur the input video without impacting the outlines.
+
+The filter accepts the following parameters:
+@var{luma_radius}:@var{luma_strength}:@var{luma_threshold}[:@var{chroma_radius}:@var{chroma_strength}:@var{chroma_threshold}]
+
+Parameters prefixed by @var{luma} indicate that they work on the
+luminance of the pixels whereas parameters prefixed by @var{chroma}
+refer to the chrominance of the pixels.
+
+If the chroma parameters are not set, the luma parameters are used for
+either the luminance and the chrominance of the pixels.
+
+@var{luma_radius} or @var{chroma_radius} must be a float number in the
+range [0.1,5.0] that specifies the variance of the gaussian filter
+used to blur the image (slower if larger).
+
+@var{luma_strength} or @var{chroma_strength} must be a float number in
+the range [-1.0,1.0] that configures the blurring. A value included in
+[0.0,1.0] will blur the image whereas a value included in [-1.0,0.0]
+will sharpen the image.
+
+@var{luma_threshold} or @var{chroma_threshold} must be an integer in
+the range [-30,30] that is used as a coefficient to determine whether
+a pixel should be blurred or not. A value of 0 will filter all the
+image, a value included in [0,30] will filter flat areas and a value
+included in [-30,0] will filter edges.
+
 @section split
 
 Split input video into several identical outputs.

libavfilter/Makefile

@@ -14,6 +14,7 @@ FFLIBS-$(CONFIG_MOVIE_FILTER)                += avformat avcodec
 FFLIBS-$(CONFIG_PAN_FILTER)                  += swresample
 FFLIBS-$(CONFIG_REMOVELOGO_FILTER)           += avformat avcodec
 FFLIBS-$(CONFIG_MP_FILTER)                   += avcodec postproc
+FFLIBS-$(CONFIG_SMARTBLUR_FILTER)            += swscale
 
 HEADERS = asrc_abuffer.h                                                \
           avcodec.h                                                     \
@@ -125,6 +126,7 @@ OBJS-$(CONFIG_SETSAR_FILTER)                 += vf_aspect.o
 OBJS-$(CONFIG_SETTB_FILTER)                  += f_settb.o
 OBJS-$(CONFIG_SHOWINFO_FILTER)               += vf_showinfo.o
 OBJS-$(CONFIG_SLICIFY_FILTER)                += vf_slicify.o
+OBJS-$(CONFIG_SMARTBLUR_FILTER)              += vf_smartblur.o
 OBJS-$(CONFIG_SPLIT_FILTER)                  += split.o
 OBJS-$(CONFIG_SUPER2XSAI_FILTER)             += vf_super2xsai.o
 OBJS-$(CONFIG_SWAPUV_FILTER)                 += vf_swapuv.o

libavfilter/allfilters.c

@@ -116,6 +116,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (SETTB,       settb,       vf);
     REGISTER_FILTER (SHOWINFO,    showinfo,    vf);
     REGISTER_FILTER (SLICIFY,     slicify,     vf);
+    REGISTER_FILTER (SMARTBLUR,   smartblur,   vf);
     REGISTER_FILTER (SPLIT,       split,       vf);
     REGISTER_FILTER (SUPER2XSAI,  super2xsai,  vf);
     REGISTER_FILTER (SWAPUV,      swapuv,      vf);

libavfilter/version.h

@@ -29,8 +29,8 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  3
-#define LIBAVFILTER_VERSION_MINOR  13
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MINOR  14
+#define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \

libavfilter/vf_smartblur.c

+/*
+ * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
+ * Copyright (c) 2012 Jeremy Tran
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU 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
+ * Apply a smartblur filter to the input video
+ * Ported from MPlayer libmpcodecs/vf_smartblur.c by Michael Niedermayer.
+ */
+
+#include "libavutil/pixdesc.h"
+#include "libswscale/swscale.h"
+
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+
+#define RADIUS_MIN 0.1
+#define RADIUS_MAX 5.0
+
+#define STRENGTH_MIN -1.0
+#define STRENGTH_MAX 1.0
+
+#define THRESHOLD_MIN -30
+#define THRESHOLD_MAX 30
+
+typedef struct {
+    float              radius;
+    float              strength;
+    int                threshold;
+    float              quality;
+    struct SwsContext *filter_context;
+} FilterParam;
+
+typedef struct {
+    FilterParam  luma;
+    FilterParam  chroma;
+    int          hsub;
+    int          vsub;
+    unsigned int sws_flags;
+} SmartblurContext;
+
+#define CHECK_PARAM(param, name, min, max, format, ret)                       \
+    if (param < min || param > max) {                                         \
+        av_log(ctx, AV_LOG_ERROR,                                             \
+               "Invalid " #name " value " #format ": "                        \
+               "must be included between range " #format " and " #format "\n",\
+               param, min, max);                                              \
+        ret = AVERROR(EINVAL);                                                \
+    }
+
+static av_cold int init(AVFilterContext *ctx, const char *args)
+{
+    SmartblurContext *sblur = ctx->priv;
+    int n = 0, ret = 0;
+    float lradius, lstrength, cradius, cstrength;
+    int lthreshold, cthreshold;
+
+    if (args)
+        n = sscanf(args, "%f:%f:%d:%f:%f:%d",
+                   &lradius, &lstrength, &lthreshold,
+                   &cradius, &cstrength, &cthreshold);
+
+    if (n != 3 && n != 6) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Incorrect number of parameters or invalid syntax: "
+               "must be luma_radius:luma_strength:luma_threshold"
+               "[:chroma_radius:chroma_strength:chroma_threshold]\n");
+        return AVERROR(EINVAL);
+    }
+
+    sblur->luma.radius    = lradius;
+    sblur->luma.strength  = lstrength;
+    sblur->luma.threshold = lthreshold;
+
+    if (n == 3) {
+        sblur->chroma.radius    = sblur->luma.radius;
+        sblur->chroma.strength  = sblur->luma.strength;
+        sblur->chroma.threshold = sblur->luma.threshold;
+    } else {
+        sblur->chroma.radius    = cradius;
+        sblur->chroma.strength  = cstrength;
+        sblur->chroma.threshold = cthreshold;
+    }
+
+    sblur->luma.quality = sblur->chroma.quality = 3.0;
+    sblur->sws_flags = SWS_BICUBIC;
+
+    CHECK_PARAM(lradius,    luma radius,    RADIUS_MIN,    RADIUS_MAX,    %0.1f, ret)
+    CHECK_PARAM(lstrength,  luma strength,  STRENGTH_MIN,  STRENGTH_MAX,  %0.1f, ret)
+    CHECK_PARAM(lthreshold, luma threshold, THRESHOLD_MIN, THRESHOLD_MAX, %d,    ret)
+
+    if (n != 3) {
+        CHECK_PARAM(sblur->chroma.radius,    chroma radius,    RADIUS_MIN,   RADIUS_MAX,    %0.1f, ret)
+        CHECK_PARAM(sblur->chroma.strength,  chroma strength,  STRENGTH_MIN, STRENGTH_MAX,  %0.1f, ret)
+        CHECK_PARAM(sblur->chroma.threshold, chroma threshold, THRESHOLD_MIN,THRESHOLD_MAX, %d,    ret)
+    }
+
+    return ret;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    SmartblurContext *sblur = ctx->priv;
+
+    sws_freeContext(sblur->luma.filter_context);
+    sws_freeContext(sblur->chroma.filter_context);
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum PixelFormat pix_fmts[] = {
+        PIX_FMT_YUV444P,      PIX_FMT_YUV422P,
+        PIX_FMT_YUV420P,      PIX_FMT_YUV411P,
+        PIX_FMT_YUV410P,      PIX_FMT_YUV440P,
+        PIX_FMT_GRAY8,
+        PIX_FMT_NONE
+    };
+
+    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
+
+    return 0;
+}
+
+static int alloc_sws_context(FilterParam *f, int width, int height, unsigned int flags)
+{
+    SwsVector *vec;
+    SwsFilter sws_filter;
+
+    vec = sws_getGaussianVec(f->radius, f->quality);
+
+    if (!vec)
+        return AVERROR(EINVAL);
+
+    sws_scaleVec(vec, f->strength);
+    vec->coeff[vec->length / 2] += 1.0 - f->strength;
+    sws_filter.lumH = sws_filter.lumV = vec;
+    sws_filter.chrH = sws_filter.chrV = NULL;
+    f->filter_context = sws_getCachedContext(NULL,
+                                             width, height, PIX_FMT_GRAY8,
+                                             width, height, PIX_FMT_GRAY8,
+                                             flags, &sws_filter, NULL, NULL);
+
+    sws_freeVec(vec);
+
+    if (!f->filter_context)
+        return AVERROR(EINVAL);
+
+    return 0;
+}
+
+static int config_props(AVFilterLink *inlink)
+{
+    SmartblurContext *sblur = inlink->dst->priv;
+    const AVPixFmtDescriptor *desc = &av_pix_fmt_descriptors[inlink->format];
+
+    sblur->hsub = desc->log2_chroma_w;
+    sblur->vsub = desc->log2_chroma_h;
+
+    alloc_sws_context(&sblur->luma, inlink->w, inlink->h, sblur->sws_flags);
+    alloc_sws_context(&sblur->chroma,
+                      inlink->w >> sblur->hsub, inlink->h >> sblur->vsub,
+                      sblur->sws_flags);
+
+    return 0;
+}
+
+static void blur(uint8_t       *dst, const int dst_linesize,
+                 const uint8_t *src, const int src_linesize,
+                 const int w, const int h, const int threshold,
+                 struct SwsContext *filter_context)
+{
+    int x, y;
+    int orig, filtered;
+    int diff;
+    /* Declare arrays of 4 to get aligned data */
+    const uint8_t* const src_array[4] = {src};
+    uint8_t *dst_array[4]             = {dst};
+    int src_linesize_array[4] = {src_linesize};
+    int dst_linesize_array[4] = {dst_linesize};
+
+    sws_scale(filter_context, src_array, src_linesize_array,
+              0, h, dst_array, dst_linesize_array);
+
+    if (threshold > 0) {
+        for (y = 0; y < h; ++y) {
+            for (x = 0; x < w; ++x) {
+                orig     = src[x + y * src_linesize];
+                filtered = dst[x + y * dst_linesize];
+                diff     = orig - filtered;
+
+                if (diff > 0) {
+                    if (diff > 2 * threshold)
+                        dst[x + y * dst_linesize] = orig;
+                    else if (diff > threshold)
+                        /* add 'diff' and substract 'threshold' from 'filtered' */
+                        dst[x + y * dst_linesize] = orig - threshold;
+                } else {
+                    if (-diff > 2 * threshold)
+                        dst[x + y * dst_linesize] = orig;
+                    else if (-diff > threshold)
+                        /* add 'diff' and 'threshold' to 'filtered' */
+                        dst[x + y * dst_linesize] = orig + threshold;
+                }
+            }
+        }
+    } else if (threshold < 0) {
+        for (y = 0; y < h; ++y) {
+            for (x = 0; x < w; ++x) {
+                orig     = src[x + y * src_linesize];
+                filtered = dst[x + y * dst_linesize];
+                diff     = orig - filtered;
+
+                if (diff > 0) {
+                    if (diff <= -threshold)
+                        dst[x + y * dst_linesize] = orig;
+                    else if (diff <= -2 * threshold)
+                        /* substract 'diff' and 'threshold' from 'orig' */
+                        dst[x + y * dst_linesize] = filtered - threshold;
+                } else {
+                    if (diff >= threshold)
+                        dst[x + y * dst_linesize] = orig;
+                    else if (diff >= 2 * threshold)
+                        /* add 'threshold' and substract 'diff' from 'orig' */
+                        dst[x + y * dst_linesize] = filtered + threshold;
+                }
+            }
+        }
+    }
+}
+
+static int end_frame(AVFilterLink *inlink)
+{
+    SmartblurContext  *sblur  = inlink->dst->priv;
+    AVFilterBufferRef *inpic  = inlink->cur_buf;
+    AVFilterBufferRef *outpic = inlink->dst->outputs[0]->out_buf;
+    int cw = inlink->w >> sblur->hsub;
+    int ch = inlink->h >> sblur->vsub;
+
+    blur(outpic->data[0], outpic->linesize[0],
+         inpic->data[0],  inpic->linesize[0],
+         inlink->w, inlink->h, sblur->luma.threshold,
+         sblur->luma.filter_context);
+
+    if (inpic->data[2]) {
+        blur(outpic->data[1], outpic->linesize[1],
+             inpic->data[1],  inpic->linesize[1],
+             cw, ch, sblur->chroma.threshold,
+             sblur->chroma.filter_context);
+        blur(outpic->data[2], outpic->linesize[2],
+             inpic->data[2],  inpic->linesize[2],
+             cw, ch, sblur->chroma.threshold,
+             sblur->chroma.filter_context);
+    }
+
+    return ff_end_frame(inlink->dst->outputs[0]);
+}
+
+AVFilter avfilter_vf_smartblur = {
+    .name        = "smartblur",
+    .description = NULL_IF_CONFIG_SMALL("Blur the input video without impacting the outlines."),
+
+    .priv_size = sizeof(SmartblurContext),
+
+    .init          = init,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+
+    .inputs = (const AVFilterPad[]) {
+        {
+            .name         = "default",
+            .type         = AVMEDIA_TYPE_VIDEO,
+            .end_frame    = end_frame,
+            .config_props = config_props,
+            .min_perms    = AV_PERM_READ,
+        },
+        { .name = NULL }
+    },
+    .outputs = (const AVFilterPad[]) {
+        {
+            .name         = "default",
+            .type         = AVMEDIA_TYPE_VIDEO,
+        },
+        { .name = NULL }
+    }
+};