avfilter: add limitdiff video filter

Changelog

@@ -26,6 +26,7 @@ version <next>:
 - GEM Raster image decoder
 - asdr audio filter
 - speex decoder
+- limitdiff video filter
 
 
 version 4.4:

doc/filters.texi

@@ -14488,6 +14488,37 @@ ffmpeg -i main.mpg -i ref.mkv -lavfi "[0:v]settb=AVTB,setpts=PTS-STARTPTS[main];
 @end example
 @end itemize
 
+@section limitdiff
+Apply limited difference filter using second and optionally third video stream.
+
+The filter accepts the following options:
+
+@table @option
+@item threshold
+Set the threshold to use when allowing certain differences between video streams.
+Any absolute difference value lower or exact than this threshold will pick pixel components from
+first video stream.
+
+@item elasticity
+Set the elasticity of soft thresholding when processing video streams.
+This value multiplied with first one sets second threshold.
+Any absolute difference value greater or exact than second threshold will pick pixel components
+from second video stream. For values between those two threshold
+linear interpolation between first and second video stream will be used.
+
+@item reference
+Enable the reference (third) video stream processing. By default is disabled.
+If set, this video stream will be used for calculating absolute difference with first video
+stream.
+
+@item planes
+Specify which planes will be processed. Defaults to all available.
+@end table
+
+@subsection Commands
+
+This filter supports the all above options as @ref{commands} except option @samp{reference}.
+
 @section limiter
 
 Limits the pixel components values to the specified range [min, max].

libavfilter/Makefile

@@ -323,6 +323,7 @@ OBJS-$(CONFIG_LATENCY_FILTER)                += f_latency.o
 OBJS-$(CONFIG_LENSCORRECTION_FILTER)         += vf_lenscorrection.o
 OBJS-$(CONFIG_LENSFUN_FILTER)                += vf_lensfun.o
 OBJS-$(CONFIG_LIBVMAF_FILTER)                += vf_libvmaf.o framesync.o
+OBJS-$(CONFIG_LIMITDIFF_FILTER)              += vf_limitdiff.o framesync.o
 OBJS-$(CONFIG_LIMITER_FILTER)                += vf_limiter.o
 OBJS-$(CONFIG_LOOP_FILTER)                   += f_loop.o
 OBJS-$(CONFIG_LUMAKEY_FILTER)                += vf_lumakey.o

libavfilter/allfilters.c

@@ -308,6 +308,7 @@ extern const AVFilter ff_vf_latency;
 extern const AVFilter ff_vf_lenscorrection;
 extern const AVFilter ff_vf_lensfun;
 extern const AVFilter ff_vf_libvmaf;
+extern const AVFilter ff_vf_limitdiff;
 extern const AVFilter ff_vf_limiter;
 extern const AVFilter ff_vf_loop;
 extern const AVFilter ff_vf_lumakey;

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   8
-#define LIBAVFILTER_VERSION_MINOR  12
+#define LIBAVFILTER_VERSION_MINOR  13
 #define LIBAVFILTER_VERSION_MICRO 100
 
 

libavfilter/vf_limitdiff.c

@@ -0,0 +1,370 @@
+/*
+ * Copyright (c) 2021 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/pixdesc.h"
+#include "libavutil/opt.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+#include "framesync.h"
+
+typedef struct ThreadData {
+    AVFrame *filtered, *source, *reference, *dst;
+} ThreadData;
+
+typedef struct LimitDiffContext {
+    const AVClass *class;
+
+    float threshold;
+    float elasticity;
+    int reference;
+    int planes;
+
+    int thr1, thr2;
+
+    int linesize[4];
+    int planewidth[4], planeheight[4];
+    int nb_planes;
+    int depth;
+    FFFrameSync fs;
+
+    void (*limitdiff)(const uint8_t *filtered, uint8_t *dst,
+                      const uint8_t *source, const uint8_t *reference,
+                      int thr1, int thr2, int w, int depth);
+} LimitDiffContext;
+
+#define OFFSET(x) offsetof(LimitDiffContext, x)
+#define TFLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+
+static const AVOption limitdiff_options[] = {
+    { "threshold",  "set the threshold",        OFFSET(threshold),  AV_OPT_TYPE_FLOAT, {.dbl=1/255.f}, 0,   1, TFLAGS },
+    { "elasticity", "set the elasticity",       OFFSET(elasticity), AV_OPT_TYPE_FLOAT, {.dbl=2.f},     0,  10, TFLAGS },
+    { "reference",  "enable reference stream",  OFFSET(reference),  AV_OPT_TYPE_BOOL,  {.i64=0},       0,   1,  FLAGS },
+    { "planes",     "set the planes to filter", OFFSET(planes),     AV_OPT_TYPE_INT,   {.i64=0xF},     0, 0xF, TFLAGS },
+    { NULL }
+};
+
+static const enum AVPixelFormat pix_fmts[] = {
+    AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV440P,
+    AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
+    AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUV420P,
+    AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
+    AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
+    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_YUV420P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV440P12,
+    AV_PIX_FMT_YUV420P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV444P14,
+    AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
+    AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA444P9,
+    AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA444P10,
+    AV_PIX_FMT_YUVA422P12, AV_PIX_FMT_YUVA444P12,
+    AV_PIX_FMT_YUVA420P16, AV_PIX_FMT_YUVA422P16, AV_PIX_FMT_YUVA444P16,
+    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_GBRAP, AV_PIX_FMT_GBRAP10, AV_PIX_FMT_GBRAP12, AV_PIX_FMT_GBRAP16,
+    AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY9, AV_PIX_FMT_GRAY10, AV_PIX_FMT_GRAY12, AV_PIX_FMT_GRAY14, AV_PIX_FMT_GRAY16,
+    AV_PIX_FMT_NONE
+};
+
+static void limitdiff8(const uint8_t *filtered, uint8_t *dst,
+                       const uint8_t *source, const uint8_t *reference,
+                       int thr1, int thr2, int w, int depth)
+{
+    for (int x = 0; x < w; x++) {
+        const int diff = filtered[x] - source[x];
+        const int diff_ref = FFABS(filtered[x] - reference[x]);
+
+        if (diff_ref <= thr1)
+            dst[x] = filtered[x];
+        else if (diff_ref >= thr2)
+            dst[x] = source[x];
+        else
+            dst[x] = av_clip_uint8(source[x] + diff * (thr2 - diff_ref) / (thr2 - thr1));
+    }
+}
+
+static void limitdiff16(const uint8_t *ffiltered, uint8_t *ddst,
+                        const uint8_t *ssource, const uint8_t *rreference,
+                        int thr1, int thr2, int w, int depth)
+{
+    const uint16_t *source = (const uint16_t *)ssource;
+    const uint16_t *filtered = (const uint16_t *)ffiltered;
+    const uint16_t *reference = (const uint16_t *)rreference;
+    uint16_t *dst = (uint16_t *)ddst;
+
+    for (int x = 0; x < w; x++) {
+        const int diff = filtered[x] - source[x];
+        const int diff_ref = FFABS(filtered[x] - reference[x]);
+
+        if (diff_ref <= thr1)
+            dst[x] = filtered[x];
+        else if (diff_ref >= thr2)
+            dst[x] = source[x];
+        else
+            dst[x] = av_clip_uintp2_c(source[x] + diff * (thr2 - diff_ref) / (thr2 - thr1), depth);
+    }
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->dst;
+    LimitDiffContext *s = ctx->priv;
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+    int vsub, hsub, ret;
+
+    s->nb_planes = av_pix_fmt_count_planes(inlink->format);
+
+    if ((ret = av_image_fill_linesizes(s->linesize, inlink->format, inlink->w)) < 0)
+        return ret;
+
+    hsub = desc->log2_chroma_w;
+    vsub = desc->log2_chroma_h;
+    s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, vsub);
+    s->planeheight[0] = s->planeheight[3] = inlink->h;
+    s->planewidth[1]  = s->planewidth[2]  = AV_CEIL_RSHIFT(inlink->w, hsub);
+    s->planewidth[0]  = s->planewidth[3]  = inlink->w;
+
+    s->depth = desc->comp[0].depth;
+    s->thr1 = s->threshold * ((1 << s->depth) - 1);
+    s->thr2 = s->thr1 * s->elasticity;
+
+    if (desc->comp[0].depth == 8)
+        s->limitdiff = limitdiff8;
+    else
+        s->limitdiff = limitdiff16;
+
+    return 0;
+}
+
+static int limitdiff_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
+{
+    LimitDiffContext *s = ctx->priv;
+    const int depth  = s->depth;
+    ThreadData *td = arg;
+
+    for (int p = 0; p < s->nb_planes; p++) {
+        const ptrdiff_t filtered_linesize = td->filtered->linesize[p];
+        const ptrdiff_t source_linesize = td->source->linesize[p];
+        const ptrdiff_t reference_linesize = td->reference->linesize[p];
+        const ptrdiff_t dst_linesize = td->dst->linesize[p];
+        const int thr1 = s->thr1;
+        const int thr2 = s->thr2;
+        const int w = s->planewidth[p];
+        const int h = s->planeheight[p];
+        const int slice_start = (h * jobnr) / nb_jobs;
+        const int slice_end = (h * (jobnr+1)) / nb_jobs;
+        const uint8_t *filtered = td->filtered->data[p] + slice_start * filtered_linesize;
+        const uint8_t *source = td->source->data[p] + slice_start * source_linesize;
+        const uint8_t *reference = td->reference->data[p] + slice_start * reference_linesize;
+        uint8_t *dst = td->dst->data[p] + slice_start * dst_linesize;
+
+        if (!((1 << p) & s->planes)) {
+            av_image_copy_plane(dst, dst_linesize, filtered, filtered_linesize,
+                                s->linesize[p], slice_end - slice_start);
+            continue;
+        }
+
+        for (int y = slice_start; y < slice_end; y++) {
+            s->limitdiff(filtered, dst, source, reference, thr1, thr2, w, depth);
+
+            dst += dst_linesize;
+            filtered += filtered_linesize;
+            source  += source_linesize;
+            reference  += reference_linesize;
+        }
+    }
+
+    return 0;
+}
+
+static int process_frame(FFFrameSync *fs)
+{
+    AVFilterContext *ctx = fs->parent;
+    LimitDiffContext *s = fs->opaque;
+    AVFilterLink *outlink = ctx->outputs[0];
+    AVFrame *out, *filtered, *source, *reference = NULL;
+    int ret;
+
+    if ((ret = ff_framesync_get_frame(&s->fs, 0, &filtered, 0)) < 0 ||
+        (ret = ff_framesync_get_frame(&s->fs, 1, &source,   0)) < 0)
+        return ret;
+    if (s->reference) {
+        if ((ret = ff_framesync_get_frame(&s->fs, 2, &reference,  0)) < 0)
+            return ret;
+    }
+
+    if (ctx->is_disabled) {
+        out = av_frame_clone(filtered);
+        if (!out)
+            return AVERROR(ENOMEM);
+    } else {
+        ThreadData td;
+
+        out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+        if (!out)
+            return AVERROR(ENOMEM);
+        av_frame_copy_props(out, filtered);
+
+        td.filtered = filtered;
+        td.source = source;
+        td.reference = reference ? reference : source;
+        td.dst = out;
+
+        ff_filter_execute(ctx, limitdiff_slice, &td, NULL,
+                          FFMIN(s->planeheight[0], ff_filter_get_nb_threads(ctx)));
+    }
+    out->pts = av_rescale_q(s->fs.pts, s->fs.time_base, outlink->time_base);
+
+    return ff_filter_frame(outlink, out);
+}
+
+static int config_output(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    LimitDiffContext *s = ctx->priv;
+    AVFilterLink *filtered = ctx->inputs[0];
+    AVFilterLink *source = ctx->inputs[1];
+    FFFrameSyncIn *in;
+    int ret;
+
+    if (filtered->w != source->w || filtered->h != source->h) {
+        av_log(ctx, AV_LOG_ERROR, "First input link %s parameters "
+               "(size %dx%d) do not match the corresponding "
+               "second input link %s parameters (%dx%d)\n",
+               ctx->input_pads[0].name, filtered->w, filtered->h,
+               ctx->input_pads[1].name, source->w, source->h);
+        return AVERROR(EINVAL);
+    }
+
+    if (s->reference) {
+        AVFilterLink *reference = ctx->inputs[2];
+
+        if (filtered->w != reference->w || filtered->h != reference->h) {
+            av_log(ctx, AV_LOG_ERROR, "First input link %s parameters "
+                   "(size %dx%d) do not match the corresponding "
+                   "third input link %s parameters (%dx%d)\n",
+                   ctx->input_pads[0].name, filtered->w, filtered->h,
+                   ctx->input_pads[1].name, reference->w, reference->h);
+            return AVERROR(EINVAL);
+        }
+    }
+
+    outlink->w = filtered->w;
+    outlink->h = filtered->h;
+    outlink->sample_aspect_ratio = filtered->sample_aspect_ratio;
+    outlink->frame_rate = filtered->frame_rate;
+
+    if ((ret = ff_framesync_init(&s->fs, ctx, 2 + !!s->reference)) < 0)
+        return ret;
+
+    in = s->fs.in;
+    in[0].time_base = filtered->time_base;
+    in[1].time_base = source->time_base;
+    if (s->reference)
+        in[2].time_base = ctx->inputs[2]->time_base;
+    in[0].sync   = 1;
+    in[0].before = EXT_STOP;
+    in[0].after  = EXT_INFINITY;
+    in[1].sync   = 1;
+    in[1].before = EXT_STOP;
+    in[1].after  = EXT_INFINITY;
+    if (s->reference) {
+        in[2].sync   = 1;
+        in[2].before = EXT_STOP;
+        in[2].after  = EXT_INFINITY;
+    }
+    s->fs.opaque   = s;
+    s->fs.on_event = process_frame;
+
+    ret = ff_framesync_configure(&s->fs);
+    outlink->time_base = s->fs.time_base;
+
+    return ret;
+}
+
+static int activate(AVFilterContext *ctx)
+{
+    LimitDiffContext *s = ctx->priv;
+    return ff_framesync_activate(&s->fs);
+}
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    const LimitDiffContext *s = ctx->priv;
+    AVFilterPad pad = {
+        .name         = "filtered",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .config_props = config_input,
+    };
+    int ret;
+
+    if ((ret = ff_append_inpad(ctx, &pad)) < 0)
+        return ret;
+
+    pad.name = "source";
+    pad.config_props = NULL;
+    if ((ret = ff_append_inpad(ctx, &pad)) < 0)
+        return ret;
+
+    if (s->reference) {
+        pad.name = "reference";
+        pad.config_props = NULL;
+        if ((ret = ff_append_inpad(ctx, &pad)) < 0)
+            return ret;
+    }
+
+    return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    LimitDiffContext *s = ctx->priv;
+
+    ff_framesync_uninit(&s->fs);
+}
+
+static const AVFilterPad limitdiff_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .config_props  = config_output,
+    },
+};
+
+AVFILTER_DEFINE_CLASS(limitdiff);
+
+const AVFilter ff_vf_limitdiff = {
+    .name          = "limitdiff",
+    .description   = NULL_IF_CONFIG_SMALL("Apply filtering with limiting difference."),
+    .priv_class    = &limitdiff_class,
+    .priv_size     = sizeof(LimitDiffContext),
+    .init          = init,
+    .uninit        = uninit,
+    .activate      = activate,
+    FILTER_OUTPUTS(limitdiff_outputs),
+    FILTER_PIXFMTS_ARRAY(pix_fmts),
+    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL |
+                     AVFILTER_FLAG_SLICE_THREADS |
+                     AVFILTER_FLAG_DYNAMIC_INPUTS,
+    .process_command = ff_filter_process_command,
+};