Browse code

avfilter: add multiband compand filter

Signed-off-by: Paul B Mahol <onemda@gmail.com>

Paul B Mahol authored on 2017/05/13 18:57:42
Showing 6 changed files
... ...
@@ -15,6 +15,7 @@ version <next>:
15 15
 - Raw aptX muxer and demuxer
16 16
 - NVIDIA NVDEC-accelerated H.264, HEVC, VC1 and VP9 hwaccel decoding
17 17
 - Intel QSV-accelerated overlay filter
18
+- mcompand audio filter
18 19
 
19 20
 
20 21
 version 3.4:
... ...
@@ -3270,6 +3270,22 @@ lowpass=c=LFE
3270 3270
 @end example
3271 3271
 @end itemize
3272 3272
 
3273
+@section mcompand
3274
+Multiband Compress or expand the audio's dynamic range.
3275
+
3276
+The input audio is divided into bands using 4th order Linkwitz-Riley IIRs.
3277
+This is akin to the crossover of a loudspeaker, and results in flat frequency
3278
+response when absent compander action.
3279
+
3280
+It accepts the following parameters:
3281
+
3282
+@table @option
3283
+@item args
3284
+This option syntax is:
3285
+attack,decay,[attack,decay..] soft-knee points crossover_frequency [delay [initial_volume [gain]]] | attack,decay ...
3286
+For explanation of each item refer to compand filter documentation.
3287
+@end table
3288
+
3273 3289
 @anchor{pan}
3274 3290
 @section pan
3275 3291
 
... ...
@@ -101,6 +101,7 @@ OBJS-$(CONFIG_JOIN_FILTER)                   += af_join.o
101 101
 OBJS-$(CONFIG_LADSPA_FILTER)                 += af_ladspa.o
102 102
 OBJS-$(CONFIG_LOUDNORM_FILTER)               += af_loudnorm.o ebur128.o
103 103
 OBJS-$(CONFIG_LOWPASS_FILTER)                += af_biquads.o
104
+OBJS-$(CONFIG_MCOMPAND_FILTER)               += af_mcompand.o
104 105
 OBJS-$(CONFIG_PAN_FILTER)                    += af_pan.o
105 106
 OBJS-$(CONFIG_REPLAYGAIN_FILTER)             += af_replaygain.o
106 107
 OBJS-$(CONFIG_RESAMPLE_FILTER)               += af_resample.o
107 108
new file mode 100644
... ...
@@ -0,0 +1,689 @@
0
+/*
1
+ * COpyright (c) 2002 Daniel Pouzzner
2
+ * Copyright (c) 1999 Chris Bagwell
3
+ * Copyright (c) 1999 Nick Bailey
4
+ * Copyright (c) 2007 Rob Sykes <robs@users.sourceforge.net>
5
+ * Copyright (c) 2013 Paul B Mahol
6
+ * Copyright (c) 2014 Andrew Kelley
7
+ *
8
+ * This file is part of FFmpeg.
9
+ *
10
+ * FFmpeg is free software; you can redistribute it and/or
11
+ * modify it under the terms of the GNU Lesser General Public
12
+ * License as published by the Free Software Foundation; either
13
+ * version 2.1 of the License, or (at your option) any later version.
14
+ *
15
+ * FFmpeg is distributed in the hope that it will be useful,
16
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
17
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18
+ * Lesser General Public License for more details.
19
+ *
20
+ * You should have received a copy of the GNU Lesser General Public
21
+ * License along with FFmpeg; if not, write to the Free Software
22
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23
+ */
24
+
25
+/**
26
+ * @file
27
+ * audio multiband compand filter
28
+ */
29
+
30
+#include "libavutil/avassert.h"
31
+#include "libavutil/avstring.h"
32
+#include "libavutil/ffmath.h"
33
+#include "libavutil/opt.h"
34
+#include "libavutil/samplefmt.h"
35
+#include "audio.h"
36
+#include "avfilter.h"
37
+#include "internal.h"
38
+
39
+typedef struct CompandSegment {
40
+    double x, y;
41
+    double a, b;
42
+} CompandSegment;
43
+
44
+typedef struct CompandT {
45
+    CompandSegment *segments;
46
+    int nb_segments;
47
+    double in_min_lin;
48
+    double out_min_lin;
49
+    double curve_dB;
50
+    double gain_dB;
51
+} CompandT;
52
+
53
+#define N 4
54
+
55
+typedef struct PrevCrossover {
56
+    double in;
57
+    double out_low;
58
+    double out_high;
59
+} PrevCrossover[N * 2];
60
+
61
+typedef struct Crossover {
62
+  PrevCrossover *previous;
63
+  size_t         pos;
64
+  double         coefs[3 *(N+1)];
65
+} Crossover;
66
+
67
+typedef struct CompBand {
68
+    CompandT transfer_fn;
69
+    double *attack_rate;
70
+    double *decay_rate;
71
+    double *volume;
72
+    double delay;
73
+    double topfreq;
74
+    Crossover filter;
75
+    AVFrame *delay_buf;
76
+    size_t delay_size;
77
+    ptrdiff_t delay_buf_ptr;
78
+    size_t delay_buf_cnt;
79
+} CompBand;
80
+
81
+typedef struct MCompandContext {
82
+    const AVClass *class;
83
+
84
+    char *args;
85
+
86
+    int nb_bands;
87
+    CompBand *bands;
88
+    AVFrame *band_buf1, *band_buf2, *band_buf3;
89
+    int band_samples;
90
+    size_t delay_buf_size;
91
+} MCompandContext;
92
+
93
+#define OFFSET(x) offsetof(MCompandContext, x)
94
+#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
95
+
96
+static const AVOption mcompand_options[] = {
97
+    { "args", "set parameters for each band", OFFSET(args), AV_OPT_TYPE_STRING, { .str = "0.005,0.1 6 -47/-40,-34/-34,-17/-33 100 | 0.003,0.05 6 -47/-40,-34/-34,-17/-33 400 | 0.000625,0.0125 6 -47/-40,-34/-34,-15/-33 1600 | 0.0001,0.025 6 -47/-40,-34/-34,-31/-31,-0/-30 6400 | 0,0.025 6 -38/-31,-28/-28,-0/-25 22000" }, 0, 0, A },
98
+    { NULL }
99
+};
100
+
101
+AVFILTER_DEFINE_CLASS(mcompand);
102
+
103
+static av_cold void uninit(AVFilterContext *ctx)
104
+{
105
+    MCompandContext *s = ctx->priv;
106
+    int i;
107
+
108
+    av_frame_free(&s->band_buf1);
109
+    av_frame_free(&s->band_buf2);
110
+    av_frame_free(&s->band_buf3);
111
+
112
+    if (s->bands) {
113
+        for (i = 0; i < s->nb_bands; i++) {
114
+            av_freep(&s->bands[i].attack_rate);
115
+            av_freep(&s->bands[i].decay_rate);
116
+            av_freep(&s->bands[i].volume);
117
+            av_freep(&s->bands[i].transfer_fn.segments);
118
+            av_freep(&s->bands[i].filter.previous);
119
+            av_frame_free(&s->bands[i].delay_buf);
120
+        }
121
+    }
122
+    av_freep(&s->bands);
123
+}
124
+
125
+static int query_formats(AVFilterContext *ctx)
126
+{
127
+    AVFilterChannelLayouts *layouts;
128
+    AVFilterFormats *formats;
129
+    static const enum AVSampleFormat sample_fmts[] = {
130
+        AV_SAMPLE_FMT_DBLP,
131
+        AV_SAMPLE_FMT_NONE
132
+    };
133
+    int ret;
134
+
135
+    layouts = ff_all_channel_counts();
136
+    if (!layouts)
137
+        return AVERROR(ENOMEM);
138
+    ret = ff_set_common_channel_layouts(ctx, layouts);
139
+    if (ret < 0)
140
+        return ret;
141
+
142
+    formats = ff_make_format_list(sample_fmts);
143
+    if (!formats)
144
+        return AVERROR(ENOMEM);
145
+    ret = ff_set_common_formats(ctx, formats);
146
+    if (ret < 0)
147
+        return ret;
148
+
149
+    formats = ff_all_samplerates();
150
+    if (!formats)
151
+        return AVERROR(ENOMEM);
152
+    return ff_set_common_samplerates(ctx, formats);
153
+}
154
+
155
+static void count_items(char *item_str, int *nb_items, char delimiter)
156
+{
157
+    char *p;
158
+
159
+    *nb_items = 1;
160
+    for (p = item_str; *p; p++) {
161
+        if (*p == delimiter)
162
+            (*nb_items)++;
163
+    }
164
+}
165
+
166
+static void update_volume(CompBand *cb, double in, int ch)
167
+{
168
+    double delta = in - cb->volume[ch];
169
+
170
+    if (delta > 0.0)
171
+        cb->volume[ch] += delta * cb->attack_rate[ch];
172
+    else
173
+        cb->volume[ch] += delta * cb->decay_rate[ch];
174
+}
175
+
176
+static double get_volume(CompandT *s, double in_lin)
177
+{
178
+    CompandSegment *cs;
179
+    double in_log, out_log;
180
+    int i;
181
+
182
+    if (in_lin <= s->in_min_lin)
183
+        return s->out_min_lin;
184
+
185
+    in_log = log(in_lin);
186
+
187
+    for (i = 1; i < s->nb_segments; i++)
188
+        if (in_log <= s->segments[i].x)
189
+            break;
190
+    cs = &s->segments[i - 1];
191
+    in_log -= cs->x;
192
+    out_log = cs->y + in_log * (cs->a * in_log + cs->b);
193
+
194
+    return exp(out_log);
195
+}
196
+
197
+static int parse_points(char *points, int nb_points, double radius,
198
+                        CompandT *s, AVFilterContext *ctx)
199
+{
200
+    int new_nb_items, num;
201
+    char *saveptr = NULL;
202
+    char *p = points;
203
+    int i;
204
+
205
+#define S(x) s->segments[2 * ((x) + 1)]
206
+    for (i = 0, new_nb_items = 0; i < nb_points; i++) {
207
+        char *tstr = av_strtok(p, ",", &saveptr);
208
+        p = NULL;
209
+        if (!tstr || sscanf(tstr, "%lf/%lf", &S(i).x, &S(i).y) != 2) {
210
+            av_log(ctx, AV_LOG_ERROR,
211
+                    "Invalid and/or missing input/output value.\n");
212
+            return AVERROR(EINVAL);
213
+        }
214
+        if (i && S(i - 1).x > S(i).x) {
215
+            av_log(ctx, AV_LOG_ERROR,
216
+                    "Transfer function input values must be increasing.\n");
217
+            return AVERROR(EINVAL);
218
+        }
219
+        S(i).y -= S(i).x;
220
+        av_log(ctx, AV_LOG_DEBUG, "%d: x=%f y=%f\n", i, S(i).x, S(i).y);
221
+        new_nb_items++;
222
+    }
223
+    num = new_nb_items;
224
+
225
+    /* Add 0,0 if necessary */
226
+    if (num == 0 || S(num - 1).x)
227
+        num++;
228
+
229
+#undef S
230
+#define S(x) s->segments[2 * (x)]
231
+    /* Add a tail off segment at the start */
232
+    S(0).x = S(1).x - 2 * s->curve_dB;
233
+    S(0).y = S(1).y;
234
+    num++;
235
+
236
+    /* Join adjacent colinear segments */
237
+    for (i = 2; i < num; i++) {
238
+        double g1 = (S(i - 1).y - S(i - 2).y) * (S(i - 0).x - S(i - 1).x);
239
+        double g2 = (S(i - 0).y - S(i - 1).y) * (S(i - 1).x - S(i - 2).x);
240
+        int j;
241
+
242
+        if (fabs(g1 - g2))
243
+            continue;
244
+        num--;
245
+        for (j = --i; j < num; j++)
246
+            S(j) = S(j + 1);
247
+    }
248
+
249
+    for (i = 0; i < s->nb_segments; i += 2) {
250
+        s->segments[i].y += s->gain_dB;
251
+        s->segments[i].x *= M_LN10 / 20;
252
+        s->segments[i].y *= M_LN10 / 20;
253
+    }
254
+
255
+#define L(x) s->segments[i - (x)]
256
+    for (i = 4; i < s->nb_segments; i += 2) {
257
+        double x, y, cx, cy, in1, in2, out1, out2, theta, len, r;
258
+
259
+        L(4).a = 0;
260
+        L(4).b = (L(2).y - L(4).y) / (L(2).x - L(4).x);
261
+
262
+        L(2).a = 0;
263
+        L(2).b = (L(0).y - L(2).y) / (L(0).x - L(2).x);
264
+
265
+        theta = atan2(L(2).y - L(4).y, L(2).x - L(4).x);
266
+        len = hypot(L(2).x - L(4).x, L(2).y - L(4).y);
267
+        r = FFMIN(radius, len);
268
+        L(3).x = L(2).x - r * cos(theta);
269
+        L(3).y = L(2).y - r * sin(theta);
270
+
271
+        theta = atan2(L(0).y - L(2).y, L(0).x - L(2).x);
272
+        len = hypot(L(0).x - L(2).x, L(0).y - L(2).y);
273
+        r = FFMIN(radius, len / 2);
274
+        x = L(2).x + r * cos(theta);
275
+        y = L(2).y + r * sin(theta);
276
+
277
+        cx = (L(3).x + L(2).x + x) / 3;
278
+        cy = (L(3).y + L(2).y + y) / 3;
279
+
280
+        L(2).x = x;
281
+        L(2).y = y;
282
+
283
+        in1  = cx - L(3).x;
284
+        out1 = cy - L(3).y;
285
+        in2  = L(2).x - L(3).x;
286
+        out2 = L(2).y - L(3).y;
287
+        L(3).a = (out2 / in2 - out1 / in1) / (in2 - in1);
288
+        L(3).b = out1 / in1 - L(3).a * in1;
289
+    }
290
+    L(3).x = 0;
291
+    L(3).y = L(2).y;
292
+
293
+    s->in_min_lin  = exp(s->segments[1].x);
294
+    s->out_min_lin = exp(s->segments[1].y);
295
+
296
+    return 0;
297
+}
298
+
299
+static void square_quadratic(double const *x, double *y)
300
+{
301
+    y[0] = x[0] * x[0];
302
+    y[1] = 2 * x[0] * x[1];
303
+    y[2] = 2 * x[0] * x[2] + x[1] * x[1];
304
+    y[3] = 2 * x[1] * x[2];
305
+    y[4] = x[2] * x[2];
306
+}
307
+
308
+static int crossover_setup(AVFilterLink *outlink, Crossover *p, double frequency)
309
+{
310
+    double w0 = 2 * M_PI * frequency / outlink->sample_rate;
311
+    double Q = sqrt(.5), alpha = sin(w0) / (2*Q);
312
+    double x[9], norm;
313
+    int i;
314
+
315
+    if (w0 > M_PI)
316
+        return AVERROR(EINVAL);
317
+
318
+    x[0] =  (1 - cos(w0))/2;           /* Cf. filter_LPF in biquads.c */
319
+    x[1] =   1 - cos(w0);
320
+    x[2] =  (1 - cos(w0))/2;
321
+    x[3] =  (1 + cos(w0))/2;           /* Cf. filter_HPF in biquads.c */
322
+    x[4] = -(1 + cos(w0));
323
+    x[5] =  (1 + cos(w0))/2;
324
+    x[6] =   1 + alpha;
325
+    x[7] =  -2*cos(w0);
326
+    x[8] =   1 - alpha;
327
+
328
+    for (norm = x[6], i = 0; i < 9; ++i)
329
+        x[i] /= norm;
330
+
331
+    square_quadratic(x    , p->coefs);
332
+    square_quadratic(x + 3, p->coefs + 5);
333
+    square_quadratic(x + 6, p->coefs + 10);
334
+
335
+    p->previous = av_calloc(outlink->channels, sizeof(*p->previous));
336
+    if (!p->previous)
337
+        return AVERROR(ENOMEM);
338
+
339
+    return 0;
340
+}
341
+
342
+static int config_output(AVFilterLink *outlink)
343
+{
344
+    AVFilterContext *ctx  = outlink->src;
345
+    MCompandContext *s    = ctx->priv;
346
+    int ret, ch, i, k, new_nb_items, nb_bands;
347
+    char *p = s->args, *saveptr = NULL;
348
+    int max_delay_size = 0;
349
+
350
+    count_items(s->args, &nb_bands, '|');
351
+    s->nb_bands = FFMAX(1, nb_bands);
352
+
353
+    s->bands = av_calloc(nb_bands, sizeof(*s->bands));
354
+    if (!s->bands)
355
+        return AVERROR(ENOMEM);
356
+
357
+    for (i = 0, new_nb_items = 0; i < nb_bands; i++) {
358
+        int nb_points, nb_attacks, nb_items = 0;
359
+        char *tstr2, *tstr = av_strtok(p, "|", &saveptr);
360
+        char *p2, *p3, *saveptr2 = NULL, *saveptr3 = NULL;
361
+        double radius;
362
+
363
+        if (!tstr) {
364
+            uninit(ctx);
365
+            return AVERROR(EINVAL);
366
+        }
367
+        p = NULL;
368
+
369
+        p2 = tstr;
370
+        count_items(tstr, &nb_items, ' ');
371
+        tstr2 = av_strtok(p2, " ", &saveptr2);
372
+        if (!tstr2) {
373
+            av_log(ctx, AV_LOG_ERROR, "at least one attacks/decays rate is mandatory\n");
374
+            uninit(ctx);
375
+            return AVERROR(EINVAL);
376
+        }
377
+        p2 = NULL;
378
+        p3 = tstr2;
379
+
380
+        count_items(tstr2, &nb_attacks, ',');
381
+        if (!nb_attacks || nb_attacks & 1) {
382
+            av_log(ctx, AV_LOG_ERROR, "number of attacks rate plus decays rate must be even\n");
383
+            uninit(ctx);
384
+            return AVERROR(EINVAL);
385
+        }
386
+
387
+        s->bands[i].attack_rate = av_calloc(outlink->channels, sizeof(double));
388
+        s->bands[i].decay_rate = av_calloc(outlink->channels, sizeof(double));
389
+        s->bands[i].volume = av_calloc(outlink->channels, sizeof(double));
390
+        for (k = 0; k < FFMIN(nb_attacks / 2, outlink->channels); k++) {
391
+            char *tstr3 = av_strtok(p3, ",", &saveptr3);
392
+
393
+            p3 = NULL;
394
+            sscanf(tstr3, "%lf", &s->bands[i].attack_rate[k]);
395
+            tstr3 = av_strtok(p3, ",", &saveptr3);
396
+            sscanf(tstr3, "%lf", &s->bands[i].decay_rate[k]);
397
+
398
+            if (s->bands[i].attack_rate[k] > 1.0 / outlink->sample_rate) {
399
+                s->bands[i].attack_rate[k] = 1.0 - exp(-1.0 / (outlink->sample_rate * s->bands[i].attack_rate[k]));
400
+            } else {
401
+                s->bands[i].attack_rate[k] = 1.0;
402
+            }
403
+
404
+            if (s->bands[i].decay_rate[k] > 1.0 / outlink->sample_rate) {
405
+                s->bands[i].decay_rate[k] = 1.0 - exp(-1.0 / (outlink->sample_rate * s->bands[i].decay_rate[k]));
406
+            } else {
407
+                s->bands[i].decay_rate[k] = 1.0;
408
+            }
409
+        }
410
+
411
+        for (ch = k; ch < outlink->channels; ch++) {
412
+            s->bands[i].attack_rate[ch] = s->bands[i].attack_rate[k - 1];
413
+            s->bands[i].decay_rate[ch]  = s->bands[i].decay_rate[k - 1];
414
+        }
415
+
416
+        tstr2 = av_strtok(p2, " ", &saveptr2);
417
+        if (!tstr2) {
418
+            av_log(ctx, AV_LOG_ERROR, "transfer function curve in dB must be set\n");
419
+            uninit(ctx);
420
+            return AVERROR(EINVAL);
421
+        }
422
+        sscanf(tstr2, "%lf", &s->bands[i].transfer_fn.curve_dB);
423
+
424
+        radius = s->bands[i].transfer_fn.curve_dB * M_LN10 / 20.0;
425
+
426
+        tstr2 = av_strtok(p2, " ", &saveptr2);
427
+        if (!tstr2) {
428
+            av_log(ctx, AV_LOG_ERROR, "transfer points missing\n");
429
+            uninit(ctx);
430
+            return AVERROR(EINVAL);
431
+        }
432
+
433
+        count_items(tstr2, &nb_points, ',');
434
+        s->bands[i].transfer_fn.nb_segments = (nb_points + 4) * 2;
435
+        s->bands[i].transfer_fn.segments = av_calloc(s->bands[i].transfer_fn.nb_segments,
436
+                                                     sizeof(CompandSegment));
437
+        if (!s->bands[i].transfer_fn.segments) {
438
+            uninit(ctx);
439
+            return AVERROR(ENOMEM);
440
+        }
441
+
442
+        ret = parse_points(tstr2, nb_points, radius, &s->bands[i].transfer_fn, ctx);
443
+        if (ret < 0) {
444
+            av_log(ctx, AV_LOG_ERROR, "transfer points parsing failed\n");
445
+            uninit(ctx);
446
+            return ret;
447
+        }
448
+
449
+        tstr2 = av_strtok(p2, " ", &saveptr2);
450
+        if (!tstr2) {
451
+            av_log(ctx, AV_LOG_ERROR, "crossover_frequency is missing\n");
452
+            uninit(ctx);
453
+            return AVERROR(EINVAL);
454
+        }
455
+
456
+        new_nb_items += sscanf(tstr2, "%lf", &s->bands[i].topfreq) == 1;
457
+        if (s->bands[i].topfreq < 0 || s->bands[i].topfreq >= outlink->sample_rate / 2) {
458
+            av_log(ctx, AV_LOG_ERROR, "crossover_frequency should be >=0 and lower than half of sample rate\n");
459
+            uninit(ctx);
460
+            return AVERROR(EINVAL);
461
+        }
462
+
463
+        if (s->bands[i].topfreq != 0) {
464
+            ret = crossover_setup(outlink, &s->bands[i].filter, s->bands[i].topfreq);
465
+            if (ret < 0) {
466
+                uninit(ctx);
467
+                return ret;
468
+            }
469
+        }
470
+
471
+        tstr2 = av_strtok(p2, " ", &saveptr2);
472
+        if (tstr2) {
473
+            sscanf(tstr2, "%lf", &s->bands[i].delay);
474
+            max_delay_size = FFMAX(max_delay_size, s->bands[i].delay * outlink->sample_rate);
475
+
476
+            tstr2 = av_strtok(p2, " ", &saveptr2);
477
+            if (tstr2) {
478
+                double initial_volume;
479
+
480
+                sscanf(tstr2, "%lf", &initial_volume);
481
+                initial_volume = pow(10.0, initial_volume / 20);
482
+
483
+                for (k = 0; k < outlink->channels; k++) {
484
+                    s->bands[i].volume[k] = initial_volume;
485
+                }
486
+
487
+                tstr2 = av_strtok(p2, " ", &saveptr2);
488
+                if (tstr2) {
489
+                    sscanf(tstr2, "%lf", &s->bands[i].transfer_fn.gain_dB);
490
+                }
491
+            }
492
+        }
493
+    }
494
+    s->nb_bands = new_nb_items;
495
+
496
+    for (i = 0; max_delay_size > 0 && i < s->nb_bands; i++) {
497
+        s->bands[i].delay_buf = ff_get_audio_buffer(outlink, max_delay_size);
498
+        if (!s->bands[i].delay_buf)
499
+            return AVERROR(ENOMEM);
500
+    }
501
+    s->delay_buf_size = max_delay_size;
502
+
503
+    return 0;
504
+}
505
+
506
+#define CONVOLVE _ _ _ _
507
+
508
+static void crossover(int ch, Crossover *p,
509
+                      double *ibuf, double *obuf_low,
510
+                      double *obuf_high, size_t len)
511
+{
512
+    double out_low, out_high;
513
+
514
+    while (len--) {
515
+        p->pos = p->pos ? p->pos - 1 : N - 1;
516
+#define _ out_low += p->coefs[j] * p->previous[ch][p->pos + j].in \
517
+            - p->coefs[2*N+2 + j] * p->previous[ch][p->pos + j].out_low, j++;
518
+        {
519
+            int j = 1;
520
+            out_low = p->coefs[0] * *ibuf;
521
+            CONVOLVE
522
+            *obuf_low++ = out_low;
523
+        }
524
+#undef _
525
+#define _ out_high += p->coefs[j+N+1] * p->previous[ch][p->pos + j].in \
526
+            - p->coefs[2*N+2 + j] * p->previous[ch][p->pos + j].out_high, j++;
527
+        {
528
+            int j = 1;
529
+            out_high = p->coefs[N+1] * *ibuf;
530
+            CONVOLVE
531
+            *obuf_high++ = out_high;
532
+        }
533
+        p->previous[ch][p->pos + N].in = p->previous[ch][p->pos].in = *ibuf++;
534
+        p->previous[ch][p->pos + N].out_low = p->previous[ch][p->pos].out_low = out_low;
535
+        p->previous[ch][p->pos + N].out_high = p->previous[ch][p->pos].out_high = out_high;
536
+    }
537
+}
538
+
539
+static int mcompand_channel(MCompandContext *c, CompBand *l, double *ibuf, double *obuf, int len, int ch)
540
+{
541
+    int i;
542
+
543
+    for (i = 0; i < len; i++) {
544
+        double level_in_lin, level_out_lin, checkbuf;
545
+        /* Maintain the volume fields by simulating a leaky pump circuit */
546
+        update_volume(l, fabs(ibuf[i]), ch);
547
+
548
+        /* Volume memory is updated: perform compand */
549
+        level_in_lin = l->volume[ch];
550
+        level_out_lin = get_volume(&l->transfer_fn, level_in_lin);
551
+
552
+        if (c->delay_buf_size <= 0) {
553
+            checkbuf = ibuf[i] * level_out_lin;
554
+            obuf[i] = checkbuf;
555
+        } else {
556
+            double *delay_buf = (double *)l->delay_buf->extended_data[ch];
557
+
558
+            /* FIXME: note that this lookahead algorithm is really lame:
559
+               the response to a peak is released before the peak
560
+               arrives. */
561
+
562
+            /* because volume application delays differ band to band, but
563
+               total delay doesn't, the volume is applied in an iteration
564
+               preceding that in which the sample goes to obuf, except in
565
+               the band(s) with the longest vol app delay.
566
+
567
+               the offset between delay_buf_ptr and the sample to apply
568
+               vol to, is a constant equal to the difference between this
569
+               band's delay and the longest delay of all the bands. */
570
+
571
+            if (l->delay_buf_cnt >= l->delay_size) {
572
+                checkbuf =
573
+                    delay_buf[(l->delay_buf_ptr +
574
+                               c->delay_buf_size -
575
+                               l->delay_size) % c->delay_buf_size] * level_out_lin;
576
+                delay_buf[(l->delay_buf_ptr + c->delay_buf_size -
577
+                           l->delay_size) % c->delay_buf_size] = checkbuf;
578
+            }
579
+            if (l->delay_buf_cnt >= c->delay_buf_size) {
580
+                obuf[i] = delay_buf[l->delay_buf_ptr];
581
+            } else {
582
+                l->delay_buf_cnt++;
583
+            }
584
+            delay_buf[l->delay_buf_ptr++] = ibuf[i];
585
+            l->delay_buf_ptr %= c->delay_buf_size;
586
+        }
587
+    }
588
+
589
+    return 0;
590
+}
591
+
592
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
593
+{
594
+    AVFilterContext  *ctx = inlink->dst;
595
+    AVFilterLink *outlink = ctx->outputs[0];
596
+    MCompandContext *s    = ctx->priv;
597
+    AVFrame *out, *abuf, *bbuf, *cbuf;
598
+    int ch, band, i;
599
+
600
+    out = ff_get_audio_buffer(outlink, in->nb_samples);
601
+    if (!out) {
602
+        av_frame_free(&in);
603
+        return AVERROR(ENOMEM);
604
+    }
605
+
606
+    if (s->band_samples < in->nb_samples) {
607
+        av_frame_free(&s->band_buf1);
608
+        av_frame_free(&s->band_buf2);
609
+        av_frame_free(&s->band_buf3);
610
+
611
+        s->band_buf1 = ff_get_audio_buffer(outlink, in->nb_samples);
612
+        s->band_buf2 = ff_get_audio_buffer(outlink, in->nb_samples);
613
+        s->band_buf3 = ff_get_audio_buffer(outlink, in->nb_samples);
614
+        s->band_samples = in->nb_samples;
615
+    }
616
+
617
+    for (ch = 0; ch < outlink->channels; ch++) {
618
+        double *a, *dst = (double *)out->extended_data[ch];
619
+
620
+        for (band = 0, abuf = in, bbuf = s->band_buf2, cbuf = s->band_buf1; band < s->nb_bands; band++) {
621
+            CompBand *b = &s->bands[band];
622
+
623
+            if (b->topfreq) {
624
+                crossover(ch, &b->filter, (double *)abuf->extended_data[ch],
625
+                          (double *)bbuf->extended_data[ch], (double *)cbuf->extended_data[ch], in->nb_samples);
626
+            } else {
627
+                bbuf = abuf;
628
+                abuf = cbuf;
629
+            }
630
+
631
+            if (abuf == in)
632
+                abuf = s->band_buf3;
633
+            mcompand_channel(s, b, (double *)bbuf->extended_data[ch], (double *)abuf->extended_data[ch], out->nb_samples, ch);
634
+            a = (double *)abuf->extended_data[ch];
635
+            for (i = 0; i < out->nb_samples; i++) {
636
+                dst[i] += a[i];
637
+            }
638
+
639
+            FFSWAP(AVFrame *, abuf, cbuf);
640
+        }
641
+    }
642
+
643
+    out->pts = in->pts;
644
+    av_frame_free(&in);
645
+    return ff_filter_frame(outlink, out);
646
+}
647
+
648
+static int request_frame(AVFilterLink *outlink)
649
+{
650
+    AVFilterContext *ctx = outlink->src;
651
+    int ret;
652
+
653
+    ret = ff_request_frame(ctx->inputs[0]);
654
+
655
+    return ret;
656
+}
657
+
658
+static const AVFilterPad mcompand_inputs[] = {
659
+    {
660
+        .name           = "default",
661
+        .type           = AVMEDIA_TYPE_AUDIO,
662
+        .filter_frame   = filter_frame,
663
+    },
664
+    { NULL }
665
+};
666
+
667
+static const AVFilterPad mcompand_outputs[] = {
668
+    {
669
+        .name          = "default",
670
+        .type          = AVMEDIA_TYPE_AUDIO,
671
+        .request_frame = request_frame,
672
+        .config_props  = config_output,
673
+    },
674
+    { NULL }
675
+};
676
+
677
+
678
+AVFilter ff_af_mcompand = {
679
+    .name           = "mcompand",
680
+    .description    = NULL_IF_CONFIG_SMALL(
681
+            "Multiband Compress or expand audio dynamic range."),
682
+    .query_formats  = query_formats,
683
+    .priv_size      = sizeof(MCompandContext),
684
+    .priv_class     = &mcompand_class,
685
+    .uninit         = uninit,
686
+    .inputs         = mcompand_inputs,
687
+    .outputs        = mcompand_outputs,
688
+};
... ...
@@ -112,6 +112,7 @@ static void register_all(void)
112 112
     REGISTER_FILTER(LADSPA,         ladspa,         af);
113 113
     REGISTER_FILTER(LOUDNORM,       loudnorm,       af);
114 114
     REGISTER_FILTER(LOWPASS,        lowpass,        af);
115
+    REGISTER_FILTER(MCOMPAND,       mcompand,       af);
115 116
     REGISTER_FILTER(PAN,            pan,            af);
116 117
     REGISTER_FILTER(REPLAYGAIN,     replaygain,     af);
117 118
     REGISTER_FILTER(RESAMPLE,       resample,       af);
... ...
@@ -30,8 +30,8 @@
30 30
 #include "libavutil/version.h"
31 31
 
32 32
 #define LIBAVFILTER_VERSION_MAJOR   7
33
-#define LIBAVFILTER_VERSION_MINOR   0
34
-#define LIBAVFILTER_VERSION_MICRO 101
33
+#define LIBAVFILTER_VERSION_MINOR   1
34
+#define LIBAVFILTER_VERSION_MICRO 100
35 35
 
36 36
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
37 37
                                                LIBAVFILTER_VERSION_MINOR, \