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/*
* Copyright (c) 2017 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/opt.h"
#include "libavutil/pixdesc.h"
#include "avfilter.h"
#include "drawutils.h"
#include "internal.h"
#include "video.h"
typedef struct EntropyContext {
const AVClass *class;
int mode;
int nb_planes;
int planeheight[4];
int planewidth[4];
int depth;
int is_rgb;
uint8_t rgba_map[4];
char planenames[4];
int64_t *histogram;
} EntropyContext;
#define OFFSET(x) offsetof(EntropyContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption entropy_options[] = {
{ "mode", "set kind of histogram entropy measurement", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, .unit = "mode" },
{ "normal", NULL, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, .unit = "mode" },
{ "diff", NULL, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, .unit = "mode" },
{ NULL }
};
AVFILTER_DEFINE_CLASS(entropy);
static const enum AVPixelFormat pixfmts[] = {
AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV411P,
AV_PIX_FMT_YUV440P,
AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ411P,
AV_PIX_FMT_YUVJ440P,
AV_PIX_FMT_YUV444P9, AV_PIX_FMT_YUV422P9, AV_PIX_FMT_YUV420P9,
AV_PIX_FMT_YUV444P10, AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV420P10,
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_YUV444P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV420P16,
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_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 int config_input(AVFilterLink *inlink)
{
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
AVFilterContext *ctx = inlink->dst;
EntropyContext *s = ctx->priv;
s->nb_planes = desc->nb_components;
s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
s->planeheight[0] = s->planeheight[3] = inlink->h;
s->planewidth[1] = s->planewidth[2] = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
s->planewidth[0] = s->planewidth[3] = inlink->w;
s->depth = desc->comp[0].depth;
s->is_rgb = ff_fill_rgba_map(s->rgba_map, inlink->format) >= 0;
s->planenames[0] = s->is_rgb ? 'R' : 'Y';
s->planenames[1] = s->is_rgb ? 'G' : 'U';
s->planenames[2] = s->is_rgb ? 'B' : 'V';
s->planenames[3] = 'A';
s->histogram = av_malloc_array(1 << s->depth, sizeof(*s->histogram));
if (!s->histogram)
return AVERROR(ENOMEM);
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
EntropyContext *s = ctx->priv;
int plane, y, x;
for (plane = 0; plane < s->nb_planes; plane++) {
int cidx = s->is_rgb ? s->rgba_map[plane] : plane;
const uint8_t *src8 = in->data[plane];
const uint16_t *src16 = (const uint16_t *)in->data[plane];
float total = s->planewidth[plane] * s->planeheight[plane];
float entropy = 0;
char metabuf[128];
char key[128];
memset(s->histogram, 0, (1 << s->depth) * sizeof(*s->histogram));
if (s->depth <= 8) {
for (y = 0; y < s->planeheight[plane]; y++) {
for (x = 0; x < s->planewidth[plane]; x++) {
s->histogram[src8[x]]++;
}
src8 += in->linesize[plane];
}
} else {
for (y = 0; y < s->planeheight[plane]; y++) {
for (x = 0; x < s->planewidth[plane]; x++) {
s->histogram[src16[x]]++;
}
src16 += in->linesize[plane] / 2;
}
}
for (y = 0; y < 1 << s->depth; y++) {
if (s->mode == 0) {
if (s->histogram[y]) {
float p = s->histogram[y] / total;
entropy += -log2(p) * p;
}
} else if (s->mode == 1) {
if (y && (s->histogram[y] - s->histogram[y - 1]) != 0) {
float p = FFABS(s->histogram[y] - s->histogram[y - 1]) / total;
entropy += -log2(p) * p;
}
}
}
snprintf(key, sizeof(key), "lavfi.entropy.entropy.%s.%c", s->mode ? "diff" : "normal", s->planenames[cidx]);
snprintf(metabuf, sizeof(metabuf), "%f", entropy);
av_dict_set(&in->metadata, key, metabuf, 0);
snprintf(key, sizeof(key), "lavfi.entropy.normalized_entropy.%s.%c", s->mode ? "diff" : "normal", s->planenames[cidx]);
snprintf(metabuf, sizeof(metabuf), "%f", entropy / log2(1 << s->depth));
av_dict_set(&in->metadata, key, metabuf, 0);
}
return ff_filter_frame(outlink, in);
}
static av_cold void uninit(AVFilterContext *ctx)
{
EntropyContext *s = ctx->priv;
av_freep(&s->histogram);
}
static const AVFilterPad inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
.config_props = config_input,
},
};
const AVFilter ff_vf_entropy = {
.name = "entropy",
.description = NULL_IF_CONFIG_SMALL("Measure video frames entropy."),
.priv_size = sizeof(EntropyContext),
.uninit = uninit,
FILTER_INPUTS(inputs),
FILTER_OUTPUTS(ff_video_default_filterpad),
FILTER_PIXFMTS_ARRAY(pixfmts),
.priv_class = &entropy_class,
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_METADATA_ONLY,
};
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