1 /*
2 * Copyright (c) 2018 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 <float.h>
22
23 #include "libavutil/ffmath.h"
24 #include "libavutil/opt.h"
25 #include "audio.h"
26 #include "avfilter.h"
27 #include "internal.h"
28
29 typedef struct ChannelStats {
30 uint64_t nb_samples;
31 uint64_t blknum;
32 float peak;
33 float sum;
34 uint32_t peaks[10001];
35 uint32_t rms[10001];
36 } ChannelStats;
37
38 typedef struct DRMeterContext {
39 const AVClass *class;
40 ChannelStats *chstats;
41 int nb_channels;
42 uint64_t tc_samples;
43 double time_constant;
44 } DRMeterContext;
45
46 #define OFFSET(x) offsetof(DRMeterContext, x)
47 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
48
49 static const AVOption drmeter_options[] = {
50 { "length", "set the window length", OFFSET(time_constant), AV_OPT_TYPE_DOUBLE, {.dbl=3}, .01, 10, FLAGS },
51 { NULL }
52 };
53
54 AVFILTER_DEFINE_CLASS(drmeter);
55
query_formats(AVFilterContext * ctx)56 static int query_formats(AVFilterContext *ctx)
57 {
58 AVFilterFormats *formats;
59 AVFilterChannelLayouts *layouts;
60 static const enum AVSampleFormat sample_fmts[] = {
61 AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_FLT,
62 AV_SAMPLE_FMT_NONE
63 };
64 int ret;
65
66 layouts = ff_all_channel_counts();
67 if (!layouts)
68 return AVERROR(ENOMEM);
69 ret = ff_set_common_channel_layouts(ctx, layouts);
70 if (ret < 0)
71 return ret;
72
73 formats = ff_make_format_list(sample_fmts);
74 if (!formats)
75 return AVERROR(ENOMEM);
76 ret = ff_set_common_formats(ctx, formats);
77 if (ret < 0)
78 return ret;
79
80 formats = ff_all_samplerates();
81 if (!formats)
82 return AVERROR(ENOMEM);
83 return ff_set_common_samplerates(ctx, formats);
84 }
85
config_output(AVFilterLink * outlink)86 static int config_output(AVFilterLink *outlink)
87 {
88 DRMeterContext *s = outlink->src->priv;
89
90 s->chstats = av_calloc(sizeof(*s->chstats), outlink->channels);
91 if (!s->chstats)
92 return AVERROR(ENOMEM);
93 s->nb_channels = outlink->channels;
94 s->tc_samples = s->time_constant * outlink->sample_rate + .5;
95
96 return 0;
97 }
98
finish_block(ChannelStats * p)99 static void finish_block(ChannelStats *p)
100 {
101 int peak_bin, rms_bin;
102 float peak, rms;
103
104 rms = sqrt(2 * p->sum / p->nb_samples);
105 peak = p->peak;
106 rms_bin = av_clip(rms * 10000, 0, 10000);
107 peak_bin = av_clip(peak * 10000, 0, 10000);
108 p->rms[rms_bin]++;
109 p->peaks[peak_bin]++;
110
111 p->peak = 0;
112 p->sum = 0;
113 p->nb_samples = 0;
114 p->blknum++;
115 }
116
update_stat(DRMeterContext * s,ChannelStats * p,float sample)117 static void update_stat(DRMeterContext *s, ChannelStats *p, float sample)
118 {
119 if (p->nb_samples >= s->tc_samples) {
120 finish_block(p);
121 }
122
123 p->peak = FFMAX(FFABS(sample), p->peak);
124 p->sum += sample * sample;
125 p->nb_samples++;
126 }
127
filter_frame(AVFilterLink * inlink,AVFrame * buf)128 static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
129 {
130 DRMeterContext *s = inlink->dst->priv;
131 const int channels = s->nb_channels;
132 int i, c;
133
134 switch (inlink->format) {
135 case AV_SAMPLE_FMT_FLTP:
136 for (c = 0; c < channels; c++) {
137 ChannelStats *p = &s->chstats[c];
138 const float *src = (const float *)buf->extended_data[c];
139
140 for (i = 0; i < buf->nb_samples; i++, src++)
141 update_stat(s, p, *src);
142 }
143 break;
144 case AV_SAMPLE_FMT_FLT: {
145 const float *src = (const float *)buf->extended_data[0];
146
147 for (i = 0; i < buf->nb_samples; i++) {
148 for (c = 0; c < channels; c++, src++)
149 update_stat(s, &s->chstats[c], *src);
150 }}
151 break;
152 }
153
154 return ff_filter_frame(inlink->dst->outputs[0], buf);
155 }
156
157 #define SQR(a) ((a)*(a))
158
print_stats(AVFilterContext * ctx)159 static void print_stats(AVFilterContext *ctx)
160 {
161 DRMeterContext *s = ctx->priv;
162 float dr = 0;
163 int ch;
164
165 for (ch = 0; ch < s->nb_channels; ch++) {
166 ChannelStats *p = &s->chstats[ch];
167 float chdr, secondpeak, rmssum = 0;
168 int i, j, first = 0;
169
170 if (!p->nb_samples) {
171 av_log(ctx, AV_LOG_INFO, "No data, dynamic range not meassurable\n");
172 return;
173 }
174
175 finish_block(p);
176
177 for (i = 0; i <= 10000; i++) {
178 if (p->peaks[10000 - i]) {
179 if (first)
180 break;
181 first = 1;
182 }
183 }
184
185 secondpeak = (10000 - i) / 10000.;
186
187 for (i = 10000, j = 0; i >= 0 && j < 0.2 * p->blknum; i--) {
188 if (p->rms[i]) {
189 rmssum += SQR(i / 10000.) * p->rms[i];
190 j += p->rms[i];
191 }
192 }
193
194 chdr = 20 * log10(secondpeak / sqrt(rmssum / (0.2 * p->blknum)));
195 dr += chdr;
196 av_log(ctx, AV_LOG_INFO, "Channel %d: DR: %.1f\n", ch + 1, chdr);
197 }
198
199 av_log(ctx, AV_LOG_INFO, "Overall DR: %.1f\n", dr / s->nb_channels);
200 }
201
uninit(AVFilterContext * ctx)202 static av_cold void uninit(AVFilterContext *ctx)
203 {
204 DRMeterContext *s = ctx->priv;
205
206 if (s->nb_channels)
207 print_stats(ctx);
208 av_freep(&s->chstats);
209 }
210
211 static const AVFilterPad drmeter_inputs[] = {
212 {
213 .name = "default",
214 .type = AVMEDIA_TYPE_AUDIO,
215 .filter_frame = filter_frame,
216 },
217 { NULL }
218 };
219
220 static const AVFilterPad drmeter_outputs[] = {
221 {
222 .name = "default",
223 .type = AVMEDIA_TYPE_AUDIO,
224 .config_props = config_output,
225 },
226 { NULL }
227 };
228
229 AVFilter ff_af_drmeter = {
230 .name = "drmeter",
231 .description = NULL_IF_CONFIG_SMALL("Measure audio dynamic range."),
232 .query_formats = query_formats,
233 .priv_size = sizeof(DRMeterContext),
234 .priv_class = &drmeter_class,
235 .uninit = uninit,
236 .inputs = drmeter_inputs,
237 .outputs = drmeter_outputs,
238 };
239