1 /*
2 * Copyright (c) 2017 Paul B Mahol
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #include "libavutil/imgutils.h"
22 #include "libavutil/opt.h"
23 #include "libavutil/pixdesc.h"
24 #include "avfilter.h"
25 #include "drawutils.h"
26 #include "formats.h"
27 #include "internal.h"
28 #include "video.h"
29
30 typedef struct EntropyContext {
31 const AVClass *class;
32
33 int mode;
34
35 int nb_planes;
36 int planeheight[4];
37 int planewidth[4];
38 int depth;
39 int is_rgb;
40 uint8_t rgba_map[4];
41 char planenames[4];
42 int64_t *histogram;
43 } EntropyContext;
44
45 #define OFFSET(x) offsetof(EntropyContext, x)
46 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
47 static const AVOption entropy_options[] = {
48 { "mode", "set kind of histogram entropy measurement", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "mode" },
49 { "normal", NULL, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "mode" },
50 { "diff", NULL, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "mode" },
51 { NULL }
52 };
53
54 AVFILTER_DEFINE_CLASS(entropy);
55
56 static const enum AVPixelFormat pixfmts[] = {
57 AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV411P,
58 AV_PIX_FMT_YUV440P,
59 AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ411P,
60 AV_PIX_FMT_YUVJ440P,
61 AV_PIX_FMT_YUV444P9, AV_PIX_FMT_YUV422P9, AV_PIX_FMT_YUV420P9,
62 AV_PIX_FMT_YUV444P10, AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV420P10,
63 AV_PIX_FMT_YUV440P10,
64 AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV420P12,
65 AV_PIX_FMT_YUV440P12,
66 AV_PIX_FMT_YUV444P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV420P14,
67 AV_PIX_FMT_YUV444P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV420P16,
68 AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRP9, AV_PIX_FMT_GBRP10,
69 AV_PIX_FMT_GBRP12, AV_PIX_FMT_GBRP14, AV_PIX_FMT_GBRP16,
70 AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY9, AV_PIX_FMT_GRAY10, AV_PIX_FMT_GRAY12, AV_PIX_FMT_GRAY14, AV_PIX_FMT_GRAY16,
71 AV_PIX_FMT_NONE
72 };
73
config_input(AVFilterLink * inlink)74 static int config_input(AVFilterLink *inlink)
75 {
76 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
77 AVFilterContext *ctx = inlink->dst;
78 EntropyContext *s = ctx->priv;
79
80 s->nb_planes = desc->nb_components;
81
82 s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
83 s->planeheight[0] = s->planeheight[3] = inlink->h;
84 s->planewidth[1] = s->planewidth[2] = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
85 s->planewidth[0] = s->planewidth[3] = inlink->w;
86
87 s->depth = desc->comp[0].depth;
88 s->is_rgb = ff_fill_rgba_map(s->rgba_map, inlink->format) >= 0;
89
90 s->planenames[0] = s->is_rgb ? 'R' : 'Y';
91 s->planenames[1] = s->is_rgb ? 'G' : 'U';
92 s->planenames[2] = s->is_rgb ? 'B' : 'V';
93 s->planenames[3] = 'A';
94
95 s->histogram = av_malloc_array(1 << s->depth, sizeof(*s->histogram));
96 if (!s->histogram)
97 return AVERROR(ENOMEM);
98
99 return 0;
100 }
101
filter_frame(AVFilterLink * inlink,AVFrame * in)102 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
103 {
104 AVFilterContext *ctx = inlink->dst;
105 AVFilterLink *outlink = ctx->outputs[0];
106 EntropyContext *s = ctx->priv;
107 int plane, y, x;
108
109 for (plane = 0; plane < s->nb_planes; plane++) {
110 int cidx = s->is_rgb ? s->rgba_map[plane] : plane;
111 const uint8_t *src8 = in->data[plane];
112 const uint16_t *src16 = (const uint16_t *)in->data[plane];
113 float total = s->planewidth[plane] * s->planeheight[plane];
114 float entropy = 0;
115 char metabuf[128];
116 char key[128];
117
118 memset(s->histogram, 0, (1 << s->depth) * sizeof(*s->histogram));
119
120 if (s->depth <= 8) {
121 for (y = 0; y < s->planeheight[plane]; y++) {
122 for (x = 0; x < s->planewidth[plane]; x++) {
123 s->histogram[src8[x]]++;
124 }
125
126 src8 += in->linesize[plane];
127 }
128 } else {
129 for (y = 0; y < s->planeheight[plane]; y++) {
130 for (x = 0; x < s->planewidth[plane]; x++) {
131 s->histogram[src16[x]]++;
132 }
133
134 src16 += in->linesize[plane] / 2;
135 }
136 }
137
138 for (y = 0; y < 1 << s->depth; y++) {
139 if (s->mode == 0) {
140 if (s->histogram[y]) {
141 float p = s->histogram[y] / total;
142 entropy += -log2(p) * p;
143 }
144 } else if (s->mode == 1) {
145 if (y && (s->histogram[y] - s->histogram[y - 1]) != 0) {
146 float p = FFABS(s->histogram[y] - s->histogram[y - 1]) / total;
147 entropy += -log2(p) * p;
148 }
149 }
150 }
151
152 snprintf(key, sizeof(key), "lavfi.entropy.entropy.%s.%c", s->mode ? "diff" : "normal", s->planenames[cidx]);
153 snprintf(metabuf, sizeof(metabuf), "%f", entropy);
154 av_dict_set(&in->metadata, key, metabuf, 0);
155 snprintf(key, sizeof(key), "lavfi.entropy.normalized_entropy.%s.%c", s->mode ? "diff" : "normal", s->planenames[cidx]);
156 snprintf(metabuf, sizeof(metabuf), "%f", entropy / log2(1 << s->depth));
157 av_dict_set(&in->metadata, key, metabuf, 0);
158 }
159
160 return ff_filter_frame(outlink, in);
161 }
162
uninit(AVFilterContext * ctx)163 static av_cold void uninit(AVFilterContext *ctx)
164 {
165 EntropyContext *s = ctx->priv;
166
167 av_freep(&s->histogram);
168 }
169
170 static const AVFilterPad inputs[] = {
171 {
172 .name = "default",
173 .type = AVMEDIA_TYPE_VIDEO,
174 .filter_frame = filter_frame,
175 .config_props = config_input,
176 },
177 };
178
179 static const AVFilterPad outputs[] = {
180 {
181 .name = "default",
182 .type = AVMEDIA_TYPE_VIDEO,
183 },
184 };
185
186 const AVFilter ff_vf_entropy = {
187 .name = "entropy",
188 .description = NULL_IF_CONFIG_SMALL("Measure video frames entropy."),
189 .priv_size = sizeof(EntropyContext),
190 .uninit = uninit,
191 FILTER_INPUTS(inputs),
192 FILTER_OUTPUTS(outputs),
193 FILTER_PIXFMTS_ARRAY(pixfmts),
194 .priv_class = &entropy_class,
195 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_METADATA_ONLY,
196 };
197