[FFmpeg-devel] [PATCH] avfilter: Add blockdetect filter
Thilo Borgmann
thilo.borgmann at mail.de
Mon May 9 15:24:31 EEST 2022
Hi,
> $subject based on http://www.eurasip.org/Proceedings/Eusipco/Eusipco2005/defevent/papers/cr1042.pdf
v2 with minimal changes from IRC.
-Thilo
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From 1a15eac35b30477e5c6d31f277819071851331c1 Mon Sep 17 00:00:00 2001
From: Thilo Borgmann <thilo.borgmann at mail.de>
Date: Mon, 9 May 2022 14:21:52 +0200
Subject: [PATCH v2] avfilter: Add blockdetect filter
---
doc/filters.texi | 29 ++++
libavfilter/Makefile | 1 +
libavfilter/allfilters.c | 1 +
libavfilter/vf_blockdetect.c | 294 +++++++++++++++++++++++++++++++++++
4 files changed, 325 insertions(+)
create mode 100644 libavfilter/vf_blockdetect.c
diff --git a/doc/filters.texi b/doc/filters.texi
index 52c40833eb..e550eb8824 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -7997,6 +7997,35 @@ tblend=all_mode=grainextract
@subsection Commands
This filter supports same @ref{commands} as options.
+ at anchor{blockdetect}
+ at section blockdetect
+
+Determines blockiness of frames without altering the input frames.
+
+Based on Remco Muijs and Ihor Kirenko: "A no-reference blocking artifact measure for adaptive video processing." 2005 13th European signal processing conference.
+
+The filter accepts the following options:
+
+ at table @option
+ at item period_min
+ at item period_max
+Set minimum and maximum values for determining pixel grids (periods).
+Default values are [3,24].
+
+ at item planes
+Set planes to filter. Default is first only.
+ at end table
+
+ at subsection Examples
+
+ at itemize
+ at item
+Determine blockiness for the first plane and search for periods within [8,32]:
+ at example
+blockdetect=period_min=8:period_max=32:planes=1
+ at end example
+ at end itemize
+
@anchor{blurdetect}
@section blurdetect
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 1db097b464..35a430878f 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -195,6 +195,7 @@ OBJS-$(CONFIG_BLACKDETECT_FILTER) += vf_blackdetect.o
OBJS-$(CONFIG_BLACKFRAME_FILTER) += vf_blackframe.o
OBJS-$(CONFIG_BLEND_FILTER) += vf_blend.o framesync.o
OBJS-$(CONFIG_BLEND_VULKAN_FILTER) += vf_blend_vulkan.o framesync.o vulkan.o vulkan_filter.o
+OBJS-$(CONFIG_BLOCKDETECT_FILTER) += vf_blockdetect.o
OBJS-$(CONFIG_BLURDETECT_FILTER) += vf_blurdetect.o edge_common.o
OBJS-$(CONFIG_BM3D_FILTER) += vf_bm3d.o framesync.o
OBJS-$(CONFIG_BOXBLUR_FILTER) += vf_boxblur.o boxblur.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 2ad523fd0f..30936392ce 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -183,6 +183,7 @@ extern const AVFilter ff_vf_blackdetect;
extern const AVFilter ff_vf_blackframe;
extern const AVFilter ff_vf_blend;
extern const AVFilter ff_vf_blend_vulkan;
+extern const AVFilter ff_vf_blockdetect;
extern const AVFilter ff_vf_blurdetect;
extern const AVFilter ff_vf_bm3d;
extern const AVFilter ff_vf_boxblur;
diff --git a/libavfilter/vf_blockdetect.c b/libavfilter/vf_blockdetect.c
new file mode 100644
index 0000000000..9d7db1885d
--- /dev/null
+++ b/libavfilter/vf_blockdetect.c
@@ -0,0 +1,294 @@
+/*
+ * Copyright (c) 2021 Thilo Borgmann <thilo.borgmann _at_ mail.de>
+ *
+ * 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
+ * No-reference blockdetect filter
+ *
+ * Implementing:
+ * Remco Muijs and Ihor Kirenko: "A no-reference blocking artifact measure for adaptive video processing." 2005 13th European signal processing conference. IEEE, 2005.
+ * http://www.eurasip.org/Proceedings/Eusipco/Eusipco2005/defevent/papers/cr1042.pdf
+ *
+ * @author Thilo Borgmann <thilo.borgmann _at_ mail.de>
+ */
+
+#include "libavutil/imgutils.h"
+#include "libavutil/opt.h"
+#include "internal.h"
+
+typedef struct BLKContext {
+ const AVClass *class;
+
+ int hsub, vsub;
+ int nb_planes;
+
+ int period_min; // minimum period to search for
+ int period_max; // maximum period to search for
+ int planes; // number of planes to filter
+
+ double block_total;
+ uint64_t nb_frames;
+
+ float *gradients;
+} BLKContext;
+
+#define OFFSET(x) offsetof(BLKContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+static const AVOption blockdetect_options[] = {
+ { "period_min", "Minimum period to search for", OFFSET(period_min), AV_OPT_TYPE_INT, {.i64=3}, 2, 32, FLAGS},
+ { "period_max", "Maximum period to search for", OFFSET(period_max), AV_OPT_TYPE_INT, {.i64=24}, 2, 64, FLAGS},
+ { "planes", "set planes to filter", OFFSET(planes), AV_OPT_TYPE_INT, {.i64=1}, 0, 15, FLAGS },
+ { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(blockdetect);
+
+static av_cold int blockdetect_init(AVFilterContext *ctx)
+{
+ return 0;
+}
+
+static int blockdetect_config_input(AVFilterLink *inlink)
+{
+ AVFilterContext *ctx = inlink->dst;
+ BLKContext *s = ctx->priv;
+ const int bufsize = inlink->w * inlink->h;
+ const AVPixFmtDescriptor *pix_desc;
+
+ pix_desc = av_pix_fmt_desc_get(inlink->format);
+ s->hsub = pix_desc->log2_chroma_w;
+ s->vsub = pix_desc->log2_chroma_h;
+ s->nb_planes = av_pix_fmt_count_planes(inlink->format);
+
+ s->gradients = av_calloc(bufsize, sizeof(*s->gradients));
+
+ if (!s->gradients)
+ return AVERROR(ENOMEM);
+
+ return 0;
+}
+
+static float calculate_blockiness(BLKContext *s, int w, int h,
+ float *grad, int grad_linesize,
+ uint8_t* src, int src_linesize)
+{
+ float block = 0.0f;
+ float nonblock = 0.0f;
+ int block_count = 0;
+ int nonblock_count = 0;
+ float ret = 0;
+
+ // Calculate BS in horizontal and vertical directions according to (1)(2)(3).
+ // Also try to find integer pixel periods (grids) even for scaled images.
+ // In case of fractional periods, FFMAX of current and neighbor pixels
+ // can help improve the correlation with MQS.
+ // Skip linear correction term (4)(5), as it appears only valid for their own test samples.
+
+ // horizontal blockiness (fixed width)
+ for (int j = 1; j < h; j++) {
+ for (int i = 3; i < w - 4; i++) {
+ float temp = 0.0f;
+ grad[j * grad_linesize + i] =
+ abs(src[j * src_linesize + i + 0] - src[j * src_linesize + i + 1]);
+ temp += abs(src[j * src_linesize + i + 1] - src[j * src_linesize + i + 2]);
+ temp += abs(src[j * src_linesize + i + 2] - src[j * src_linesize + i + 3]);
+ temp += abs(src[j * src_linesize + i + 3] - src[j * src_linesize + i + 4]);
+ temp += abs(src[j * src_linesize + i - 0] - src[j * src_linesize + i - 1]);
+ temp += abs(src[j * src_linesize + i - 1] - src[j * src_linesize + i - 2]);
+ temp += abs(src[j * src_linesize + i - 2] - src[j * src_linesize + i - 3]);
+ temp = FFMAX(1, temp);
+ grad[j * grad_linesize + i] /= temp;
+
+ // use first row to store acculated results
+ grad[i] += grad[j * grad_linesize + i];
+ }
+ }
+
+ // find horizontal period
+ for (int period = s->period_min; period < s->period_max + 1; period++) {
+ float temp;
+ block = 0;
+ nonblock = 0;
+ block_count = 0;
+ nonblock_count = 0;
+ for (int i = 3; i < w - 4; i++) {
+ if ((i % period) == (period - 1)) {
+ block += FFMAX(FFMAX(grad[i + 0], grad[i + 1]), grad[i - 1]);
+ block_count++;
+ } else {
+ nonblock += grad[i];
+ nonblock_count++;
+ }
+ }
+ temp = (block / block_count) / (nonblock / nonblock_count);
+ ret = FFMAX(ret, temp);
+ }
+
+ // vertical blockiness (fixed height)
+ block_count = 0;
+ for (int j = 3; j < h - 4; j++) {
+ for (int i = 1; i < w; i++) {
+ float temp = 0.0f;
+ grad[j * grad_linesize + i] =
+ abs(src[(j + 0) * src_linesize + i] - src[(j + 1) * src_linesize + i]);
+ temp += abs(src[(j + 1) * src_linesize + i] - src[(j + 2) * src_linesize + i]);
+ temp += abs(src[(j + 2) * src_linesize + i] - src[(j + 3) * src_linesize + i]);
+ temp += abs(src[(j + 3) * src_linesize + i] - src[(j + 4) * src_linesize + i]);
+ temp += abs(src[(j - 0) * src_linesize + i] - src[(j - 1) * src_linesize + i]);
+ temp += abs(src[(j - 1) * src_linesize + i] - src[(j - 2) * src_linesize + i]);
+ temp += abs(src[(j - 2) * src_linesize + i] - src[(j - 3) * src_linesize + i]);
+ temp = FFMAX(1, temp);
+ grad[j * grad_linesize + i] /= temp;
+
+ // use first column to store accumulated results
+ grad[j * grad_linesize] += grad[j * grad_linesize + i];
+ }
+ }
+
+ // find vertical period
+ for (int period = s->period_min; period < s->period_max + 1; period++) {
+ float temp;
+ block = 0;
+ nonblock = 0;
+ block_count = 0;
+ nonblock_count = 0;
+ for (int j = 3; j < h - 4; j++) {
+ if ((j % period) == (period - 1)) {
+ block += FFMAX(FFMAX(grad[(j + 0) * grad_linesize],
+ grad[(j + 1) * grad_linesize]),
+ grad[(j - 1) * grad_linesize]);
+ block_count++;
+ } else {
+ nonblock += grad[j * grad_linesize];
+ nonblock_count++;
+ }
+ }
+ temp = (block / block_count) / (nonblock / nonblock_count);
+ ret = FFMAX(ret, temp);
+ }
+
+ // return highest value of horz||vert
+ return ret;
+}
+
+static void set_meta(AVDictionary **metadata, const char *key, float d)
+{
+ char value[128];
+ snprintf(value, sizeof(value), "%f", d);
+ av_dict_set(metadata, key, value, 0);
+}
+
+static int blockdetect_filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+ AVFilterContext *ctx = inlink->dst;
+ BLKContext *s = ctx->priv;
+ AVFilterLink *outlink = ctx->outputs[0];
+
+ const int inw = inlink->w;
+ const int inh = inlink->h;
+
+ float *gradients = s->gradients;
+
+ float block = 0.0f;
+ int nplanes = 0;
+ AVDictionary **metadata;
+ metadata = &in->metadata;
+
+ for (int plane = 0; plane < s->nb_planes; plane++) {
+ int hsub = plane == 1 || plane == 2 ? s->hsub : 0;
+ int vsub = plane == 1 || plane == 2 ? s->vsub : 0;
+ int w = AV_CEIL_RSHIFT(inw, hsub);
+ int h = AV_CEIL_RSHIFT(inh, vsub);
+
+ if (!((1 << plane) & s->planes))
+ continue;
+
+ nplanes++;
+
+ block += calculate_blockiness(s, w, h, gradients, w, in->data[plane], in->linesize[plane]);
+ }
+
+ if (nplanes)
+ block /= nplanes;
+
+ s->block_total += block;
+
+ // write stats
+ av_log(ctx, AV_LOG_VERBOSE, "block: %.7f\n", block);
+
+ set_meta(metadata, "lavfi.block", block);
+
+ s->nb_frames = inlink->frame_count_in;
+
+ return ff_filter_frame(outlink, in);
+}
+
+static av_cold void blockdetect_uninit(AVFilterContext *ctx)
+{
+ BLKContext *s = ctx->priv;
+
+ if (s->nb_frames > 0) {
+ av_log(ctx, AV_LOG_INFO, "block mean: %.7f\n",
+ s->block_total / s->nb_frames);
+ }
+
+ av_freep(&s->gradients);
+}
+
+static const enum AVPixelFormat pix_fmts[] = {
+ AV_PIX_FMT_GRAY8,
+ AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP,
+ AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV420P,
+ AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV440P,
+ AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
+ AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUVJ420P,
+ AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P,
+ AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,
+ AV_PIX_FMT_NONE
+};
+
+static const AVFilterPad blockdetect_inputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .config_props = blockdetect_config_input,
+ .filter_frame = blockdetect_filter_frame,
+ },
+};
+
+static const AVFilterPad blockdetect_outputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ },
+};
+
+const AVFilter ff_vf_blockdetect = {
+ .name = "blockdetect",
+ .description = NULL_IF_CONFIG_SMALL("Blockdetect filter."),
+ .priv_size = sizeof(BLKContext),
+ .init = blockdetect_init,
+ .uninit = blockdetect_uninit,
+ FILTER_PIXFMTS_ARRAY(pix_fmts),
+ FILTER_INPUTS(blockdetect_inputs),
+ FILTER_OUTPUTS(blockdetect_outputs),
+ .priv_class = &blockdetect_class,
+ .flags = AVFILTER_FLAG_METADATA_ONLY,
+};
--
2.20.1 (Apple Git-117)
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