avfilter: add amplify filter

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

Changelog

@@ -4,6 +4,7 @@ releases are sorted from youngest to oldest.
 version <next>:
 - deblock filter
 - tmix filter
+- amplify filter
 
 
 version 4.0:

doc/filters.texi

@@ -5187,6 +5187,30 @@ input reaches end of stream. This will cause problems if your encoding
 pipeline drops frames. If you're trying to apply an image as an
 overlay to a video stream, consider the @var{overlay} filter instead.
 
+@section amplify
+
+Amplify differences between current pixel and pixels of adjacent frames in
+same pixel location.
+
+This filter accepts the following options:
+
+@table @option
+@item radius
+Set frame radius. Default is 2. Allowed range is from 1 to 63.
+For example radius of 3 will instruct filter to calculate average of 7 frames.
+
+@item factor
+Set factor to amplify difference. Default is 2. Allowed range is from 0 to 65535.
+
+@item threshold
+Set threshold for difference amplification. Any differrence greater or equal to
+this value will not alter source pixel. Default is 10.
+Allowed range is from 0 to 65535.
+
+@item planes
+Set which planes to filter. Default is all. Allowed range is from 0 to 15.
+@end table
+
 @section ass
 
 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec

libavfilter/Makefile

@@ -138,6 +138,7 @@ OBJS-$(CONFIG_ANULLSINK_FILTER)              += asink_anullsink.o
 # video filters
 OBJS-$(CONFIG_ALPHAEXTRACT_FILTER)           += vf_extractplanes.o
 OBJS-$(CONFIG_ALPHAMERGE_FILTER)             += vf_alphamerge.o
+OBJS-$(CONFIG_AMPLIFY_FILTER)                += vf_amplify.o
 OBJS-$(CONFIG_ASS_FILTER)                    += vf_subtitles.o
 OBJS-$(CONFIG_ATADENOISE_FILTER)             += vf_atadenoise.o
 OBJS-$(CONFIG_AVGBLUR_FILTER)                += vf_avgblur.o

libavfilter/allfilters.c

@@ -132,6 +132,7 @@ extern AVFilter ff_asink_anullsink;
 
 extern AVFilter ff_vf_alphaextract;
 extern AVFilter ff_vf_alphamerge;
+extern AVFilter ff_vf_amplify;
 extern AVFilter ff_vf_ass;
 extern AVFilter ff_vf_atadenoise;
 extern AVFilter ff_vf_avgblur;

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   7
-#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_amplify.c

+/*
+ * Copyright (c) 2018 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/imgutils.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+typedef struct AmplifyContext {
+    const AVClass *class;
+    const AVPixFmtDescriptor *desc;
+    int radius;
+    float factor;
+    float threshold;
+    int planes;
+
+    int nb_inputs;
+    int nb_frames;
+
+    int depth;
+    int max;
+    int nb_planes;
+    int linesize[4];
+    int height[4];
+
+    AVFrame **frames;
+} AmplifyContext;
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pixel_fmts[] = {
+        AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY9,
+        AV_PIX_FMT_GRAY10, AV_PIX_FMT_GRAY12,
+        AV_PIX_FMT_GRAY16,
+        AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
+        AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
+        AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
+        AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
+        AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P,
+        AV_PIX_FMT_YUVJ411P,
+        AV_PIX_FMT_YUV420P9, AV_PIX_FMT_YUV422P9, AV_PIX_FMT_YUV444P9,
+        AV_PIX_FMT_YUV420P10, AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV444P10,
+        AV_PIX_FMT_YUV440P10,
+        AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV420P12,
+        AV_PIX_FMT_YUV440P12,
+        AV_PIX_FMT_YUV444P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV420P14,
+        AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
+        AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRP9, AV_PIX_FMT_GBRP10,
+        AV_PIX_FMT_GBRP12, AV_PIX_FMT_GBRP14, AV_PIX_FMT_GBRP16,
+        AV_PIX_FMT_NONE
+    };
+    AVFilterFormats *formats = ff_make_format_list(pixel_fmts);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    return ff_set_common_formats(ctx, formats);
+}
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    AmplifyContext *s = ctx->priv;
+
+    s->nb_inputs = s->radius * 2 + 1;
+
+    s->frames = av_calloc(s->nb_inputs, sizeof(*s->frames));
+    if (!s->frames)
+        return AVERROR(ENOMEM);
+
+    return 0;
+}
+
+typedef struct ThreadData {
+    AVFrame **in, *out;
+} ThreadData;
+
+static int amplify_frame(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
+{
+    AmplifyContext *s = ctx->priv;
+    ThreadData *td = arg;
+    AVFrame **in = td->in;
+    AVFrame *out = td->out;
+    const int radius = s->radius;
+    const int nb_inputs = s->nb_inputs;
+    const float threshold = s->threshold;
+    const float factor = s->factor;
+    int i, p, x, y;
+
+    if (s->depth <= 8) {
+        for (p = 0; p < s->nb_planes; p++) {
+            const int slice_start = (s->height[p] * jobnr) / nb_jobs;
+            const int slice_end = (s->height[p] * (jobnr+1)) / nb_jobs;
+            uint8_t *dst = out->data[p] + slice_start * out->linesize[p];
+
+            if (!((1 << p) & s->planes)) {
+                av_image_copy_plane(dst, out->linesize[p],
+                                    in[radius]->data[p] + slice_start * in[radius]->linesize[p],
+                                    in[radius]->linesize[p],
+                                    s->linesize[p], slice_end - slice_start);
+                continue;
+            }
+
+            for (y = slice_start; y < slice_end; y++) {
+                for (x = 0; x < s->linesize[p]; x++) {
+                    int src = in[radius]->data[p][y * in[radius]->linesize[p] + x];
+                    float diff, avg;
+                    int sum = 0;
+
+                    for (i = 0; i < nb_inputs; i++) {
+                        sum += in[i]->data[p][y * in[i]->linesize[p] + x];
+                    }
+
+                    avg = sum / (float)nb_inputs;
+                    diff = src - avg;
+                    if (fabsf(diff) < threshold)
+                        dst[x] = av_clip_uint8(src + diff * factor);
+                    else
+                        dst[x] = src;
+                }
+
+                dst += out->linesize[p];
+            }
+        }
+    } else {
+        for (p = 0; p < s->nb_planes; p++) {
+            const int slice_start = (s->height[p] * jobnr) / nb_jobs;
+            const int slice_end = (s->height[p] * (jobnr+1)) / nb_jobs;
+            uint16_t *dst = (uint16_t *)(out->data[p] + slice_start * out->linesize[p]);
+
+            if (!((1 << p) & s->planes)) {
+                av_image_copy_plane((uint8_t *)dst, out->linesize[p],
+                                    in[radius]->data[p] + slice_start * in[radius]->linesize[p],
+                                    in[radius]->linesize[p],
+                                    s->linesize[p], slice_end - slice_start);
+                continue;
+            }
+
+            for (y = slice_start; y < slice_end; y++) {
+                for (x = 0; x < s->linesize[p] / 2; x++) {
+                    int src = AV_RN16(in[radius]->data[p] + y * in[radius]->linesize[p] + x * 2);
+                    float diff, avg;
+                    int sum = 0;
+
+                    for (i = 0; i < nb_inputs; i++) {
+                        sum += AV_RN16(in[i]->data[p] + y * in[i]->linesize[p] + x * 2);
+                    }
+
+                    avg = sum / (float)nb_inputs;
+                    diff = src - avg;
+
+                    if (fabsf(diff) < threshold)
+                        dst[x] = av_clip(src + (src - avg) * factor, 0, s->max);
+                    else
+                        dst[x] = src;
+                }
+
+                dst += out->linesize[p] / 2;
+            }
+        }
+    }
+
+    return 0;
+}
+
+static int config_output(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    AmplifyContext *s = ctx->priv;
+    AVFilterLink *inlink = ctx->inputs[0];
+    int ret;
+
+    s->desc = av_pix_fmt_desc_get(outlink->format);
+    if (!s->desc)
+        return AVERROR_BUG;
+    s->nb_planes = av_pix_fmt_count_planes(outlink->format);
+    s->depth = s->desc->comp[0].depth;
+    s->max = (1 << s->depth) - 1;
+
+    if ((ret = av_image_fill_linesizes(s->linesize, inlink->format, inlink->w)) < 0)
+        return ret;
+
+    s->height[1] = s->height[2] = AV_CEIL_RSHIFT(inlink->h, s->desc->log2_chroma_h);
+    s->height[0] = s->height[3] = inlink->h;
+
+    return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    AmplifyContext *s = ctx->priv;
+    int i;
+
+    for (i = 0; i < s->nb_frames; i++)
+        av_frame_free(&s->frames[i]);
+    av_freep(&s->frames);
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    AmplifyContext *s = ctx->priv;
+    ThreadData td;
+    AVFrame *out;
+
+    if (s->nb_frames < s->nb_inputs) {
+        s->frames[s->nb_frames] = in;
+        s->nb_frames++;
+        return 0;
+    } else {
+        av_frame_free(&s->frames[0]);
+        memmove(&s->frames[0], &s->frames[1], sizeof(*s->frames) * (s->nb_inputs - 1));
+        s->frames[s->nb_inputs - 1] = in;
+    }
+
+    out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+    if (!out)
+        return AVERROR(ENOMEM);
+    out->pts = s->frames[0]->pts;
+
+    td.out = out;
+    td.in = s->frames;
+    ctx->internal->execute(ctx, amplify_frame, &td, NULL, FFMIN(s->height[1], ff_filter_get_nb_threads(ctx)));
+
+    return ff_filter_frame(outlink, out);
+}
+
+#define OFFSET(x) offsetof(AmplifyContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption amplify_options[] = {
+    { "radius", "set radius", OFFSET(radius), AV_OPT_TYPE_INT, {.i64=2}, 1, 63, .flags = FLAGS },
+    { "factor", "set factor", OFFSET(factor), AV_OPT_TYPE_FLOAT, {.dbl=2}, 0, UINT16_MAX, .flags = FLAGS },
+    { "threshold", "set threshold", OFFSET(threshold), AV_OPT_TYPE_FLOAT, {.dbl=10}, 0, UINT16_MAX, .flags = FLAGS },
+    { "planes", "set what planes to filter", OFFSET(planes), AV_OPT_TYPE_FLAGS, {.i64=7},    0, 15,  FLAGS },
+    { NULL },
+};
+
+static const AVFilterPad inputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .filter_frame  = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .config_props  = config_output,
+    },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(amplify);
+
+AVFilter ff_vf_amplify = {
+    .name          = "amplify",
+    .description   = NULL_IF_CONFIG_SMALL("Amplify changes between successive video frames."),
+    .priv_size     = sizeof(AmplifyContext),
+    .priv_class    = &amplify_class,
+    .query_formats = query_formats,
+    .outputs       = outputs,
+    .inputs        = inputs,
+    .init          = init,
+    .uninit        = uninit,
+    .flags         = AVFILTER_FLAG_SLICE_THREADS,
+};