GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavfilter/af_aemphasis.c Lines: 162 218 74.3 %
Date: 2021-04-14 23:45:22 Branches: 27 53 50.9 %

Line Branch Exec Source
1
/*
2
 * Copyright (c) 2001-2010 Krzysztof Foltman, Markus Schmidt, Thor Harald Johansen, Damien Zammit and others
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/opt.h"
22
#include "avfilter.h"
23
#include "internal.h"
24
#include "audio.h"
25
26
typedef struct BiquadCoeffs {
27
    double a0, a1, a2, b1, b2;
28
} BiquadCoeffs;
29
30
typedef struct RIAACurve {
31
    BiquadCoeffs r1;
32
    BiquadCoeffs brickw;
33
    int use_brickw;
34
} RIAACurve;
35
36
typedef struct AudioEmphasisContext {
37
    const AVClass *class;
38
    int mode, type;
39
    double level_in, level_out;
40
41
    RIAACurve rc;
42
43
    AVFrame *w;
44
} AudioEmphasisContext;
45
46
#define OFFSET(x) offsetof(AudioEmphasisContext, x)
47
#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
48
49
static const AVOption aemphasis_options[] = {
50
    { "level_in",      "set input gain", OFFSET(level_in),  AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 64, FLAGS },
51
    { "level_out",    "set output gain", OFFSET(level_out), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 64, FLAGS },
52
    { "mode",         "set filter mode", OFFSET(mode), AV_OPT_TYPE_INT,   {.i64=0}, 0, 1, FLAGS, "mode" },
53
    { "reproduction",              NULL,            0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "mode" },
54
    { "production",                NULL,            0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "mode" },
55
    { "type",         "set filter type", OFFSET(type), AV_OPT_TYPE_INT,   {.i64=4}, 0, 8, FLAGS, "type" },
56
    { "col",                 "Columbia",            0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "type" },
57
    { "emi",                      "EMI",            0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "type" },
58
    { "bsi",              "BSI (78RPM)",            0, AV_OPT_TYPE_CONST, {.i64=2}, 0, 0, FLAGS, "type" },
59
    { "riaa",                    "RIAA",            0, AV_OPT_TYPE_CONST, {.i64=3}, 0, 0, FLAGS, "type" },
60
    { "cd",         "Compact Disc (CD)",            0, AV_OPT_TYPE_CONST, {.i64=4}, 0, 0, FLAGS, "type" },
61
    { "50fm",               "50µs (FM)",            0, AV_OPT_TYPE_CONST, {.i64=5}, 0, 0, FLAGS, "type" },
62
    { "75fm",               "75µs (FM)",            0, AV_OPT_TYPE_CONST, {.i64=6}, 0, 0, FLAGS, "type" },
63
    { "50kf",            "50µs (FM-KF)",            0, AV_OPT_TYPE_CONST, {.i64=7}, 0, 0, FLAGS, "type" },
64
    { "75kf",            "75µs (FM-KF)",            0, AV_OPT_TYPE_CONST, {.i64=8}, 0, 0, FLAGS, "type" },
65
    { NULL }
66
};
67
68
AVFILTER_DEFINE_CLASS(aemphasis);
69
70
1554
static inline void biquad_process(BiquadCoeffs *bq, double *dst, const double *src, int nb_samples,
71
                                  double *w, double level_in, double level_out)
72
{
73
1554
    const double a0 = bq->a0;
74
1554
    const double a1 = bq->a1;
75
1554
    const double a2 = bq->a2;
76
1554
    const double b1 = bq->b1;
77
1554
    const double b2 = bq->b2;
78
1554
    double w1 = w[0];
79
1554
    double w2 = w[1];
80
81
1589154
    for (int i = 0; i < nb_samples; i++) {
82
1587600
        double n = src[i] * level_in;
83
1587600
        double tmp = n - w1 * b1 - w2 * b2;
84
1587600
        double out = tmp * a0 + w1 * a1 + w2 * a2;
85
86
1587600
        w2 = w1;
87
1587600
        w1 = tmp;
88
89
1587600
        dst[i] = out * level_out;
90
    }
91
92
1554
    w[0] = w1;
93
1554
    w[1] = w2;
94
1554
}
95
96
typedef struct ThreadData {
97
    AVFrame *in, *out;
98
} ThreadData;
99
100
1036
static int filter_channels(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
101
{
102
1036
    AudioEmphasisContext *s = ctx->priv;
103
1036
    const double level_out = s->level_out;
104
1036
    const double level_in = s->level_in;
105
1036
    ThreadData *td = arg;
106
1036
    AVFrame *out = td->out;
107
1036
    AVFrame *in = td->in;
108
1036
    const int start = (in->channels * jobnr) / nb_jobs;
109
1036
    const int end = (in->channels * (jobnr+1)) / nb_jobs;
110
111
2072
    for (int ch = start; ch < end; ch++) {
112
1036
        const double *src = (const double *)in->extended_data[ch];
113
1036
        double *w = (double *)s->w->extended_data[ch];
114
1036
        double *dst = (double *)out->extended_data[ch];
115
116
1036
        if (s->rc.use_brickw) {
117
518
            biquad_process(&s->rc.brickw, dst, src, in->nb_samples, w + 2, level_in, 1.);
118
518
            biquad_process(&s->rc.r1, dst, dst, in->nb_samples, w, 1., level_out);
119
        } else {
120
518
            biquad_process(&s->rc.r1, dst, src, in->nb_samples, w, level_in, level_out);
121
        }
122
    }
123
124
1036
    return 0;
125
}
126
127
518
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
128
{
129
518
    AVFilterContext *ctx = inlink->dst;
130
518
    AVFilterLink *outlink = ctx->outputs[0];
131
    ThreadData td;
132
    AVFrame *out;
133
134
518
    if (av_frame_is_writable(in)) {
135
518
        out = in;
136
    } else {
137
        out = ff_get_audio_buffer(outlink, in->nb_samples);
138
        if (!out) {
139
            av_frame_free(&in);
140
            return AVERROR(ENOMEM);
141
        }
142
        av_frame_copy_props(out, in);
143
    }
144
145
518
    td.in = in; td.out = out;
146
518
    ctx->internal->execute(ctx, filter_channels, &td, NULL, FFMIN(inlink->channels,
147
                                                            ff_filter_get_nb_threads(ctx)));
148
149
518
    if (in != out)
150
        av_frame_free(&in);
151
518
    return ff_filter_frame(outlink, out);
152
}
153
154
2
static int query_formats(AVFilterContext *ctx)
155
{
156
    AVFilterChannelLayouts *layouts;
157
    AVFilterFormats *formats;
158
    static const enum AVSampleFormat sample_fmts[] = {
159
        AV_SAMPLE_FMT_DBLP,
160
        AV_SAMPLE_FMT_NONE
161
    };
162
    int ret;
163
164
2
    layouts = ff_all_channel_counts();
165
2
    if (!layouts)
166
        return AVERROR(ENOMEM);
167
2
    ret = ff_set_common_channel_layouts(ctx, layouts);
168
2
    if (ret < 0)
169
        return ret;
170
171
2
    formats = ff_make_format_list(sample_fmts);
172
2
    if (!formats)
173
        return AVERROR(ENOMEM);
174
2
    ret = ff_set_common_formats(ctx, formats);
175
2
    if (ret < 0)
176
        return ret;
177
178
2
    formats = ff_all_samplerates();
179
2
    if (!formats)
180
        return AVERROR(ENOMEM);
181
2
    return ff_set_common_samplerates(ctx, formats);
182
}
183
184
1
static inline void set_highshelf_rbj(BiquadCoeffs *bq, double freq, double q, double peak, double sr)
185
{
186
1
    double A = sqrt(peak);
187
1
    double w0 = freq * 2 * M_PI / sr;
188
1
    double alpha = sin(w0) / (2 * q);
189
1
    double cw0 = cos(w0);
190
1
    double tmp = 2 * sqrt(A) * alpha;
191
1
    double b0 = 0, ib0 = 0;
192
193
1
    bq->a0 =    A*( (A+1) + (A-1)*cw0 + tmp);
194
1
    bq->a1 = -2*A*( (A-1) + (A+1)*cw0);
195
1
    bq->a2 =    A*( (A+1) + (A-1)*cw0 - tmp);
196
1
        b0 =        (A+1) - (A-1)*cw0 + tmp;
197
1
    bq->b1 =    2*( (A-1) - (A+1)*cw0);
198
1
    bq->b2 =        (A+1) - (A-1)*cw0 - tmp;
199
200
1
    ib0     = 1 / b0;
201
1
    bq->b1 *= ib0;
202
1
    bq->b2 *= ib0;
203
1
    bq->a0 *= ib0;
204
1
    bq->a1 *= ib0;
205
1
    bq->a2 *= ib0;
206
1
}
207
208
2
static inline void set_lp_rbj(BiquadCoeffs *bq, double fc, double q, double sr, double gain)
209
{
210
2
    double omega = 2.0 * M_PI * fc / sr;
211
2
    double sn = sin(omega);
212
2
    double cs = cos(omega);
213
2
    double alpha = sn/(2 * q);
214
2
    double inv = 1.0/(1.0 + alpha);
215
216
2
    bq->a2 = bq->a0 = gain * inv * (1.0 - cs) * 0.5;
217
2
    bq->a1 = bq->a0 + bq->a0;
218
2
    bq->b1 = (-2.0 * cs * inv);
219
2
    bq->b2 = ((1.0 - alpha) * inv);
220
2
}
221
222
1
static double freq_gain(BiquadCoeffs *c, double freq, double sr)
223
{
224
    double zr, zi;
225
226
1
    freq *= 2.0 * M_PI / sr;
227
1
    zr = cos(freq);
228
1
    zi = -sin(freq);
229
230
    /* |(a0 + a1*z + a2*z^2)/(1 + b1*z + b2*z^2)| */
231
2
    return hypot(c->a0 + c->a1*zr + c->a2*(zr*zr-zi*zi), c->a1*zi + 2*c->a2*zr*zi) /
232
1
           hypot(1 + c->b1*zr + c->b2*(zr*zr-zi*zi), c->b1*zi + 2*c->b2*zr*zi);
233
}
234
235
2
static int config_input(AVFilterLink *inlink)
236
{
237
    double i, j, k, g, t, a0, a1, a2, b1, b2, tau1, tau2, tau3;
238
2
    double cutfreq, gain1kHz, gc, sr = inlink->sample_rate;
239
2
    AVFilterContext *ctx = inlink->dst;
240
2
    AudioEmphasisContext *s = ctx->priv;
241
    BiquadCoeffs coeffs;
242
243
2
    if (!s->w)
244
2
        s->w = ff_get_audio_buffer(inlink, 4);
245
2
    if (!s->w)
246
        return AVERROR(ENOMEM);
247
248

2
    switch (s->type) {
249
    case 0: //"Columbia"
250
        i = 100.;
251
        j = 500.;
252
        k = 1590.;
253
        break;
254
    case 1: //"EMI"
255
        i = 70.;
256
        j = 500.;
257
        k = 2500.;
258
        break;
259
    case 2: //"BSI(78rpm)"
260
        i = 50.;
261
        j = 353.;
262
        k = 3180.;
263
        break;
264
1
    case 3: //"RIAA"
265
    default:
266
1
        tau1 = 0.003180;
267
1
        tau2 = 0.000318;
268
1
        tau3 = 0.000075;
269
1
        i = 1. / (2. * M_PI * tau1);
270
1
        j = 1. / (2. * M_PI * tau2);
271
1
        k = 1. / (2. * M_PI * tau3);
272
1
        break;
273
    case 4: //"CD Mastering"
274
        tau1 = 0.000050;
275
        tau2 = 0.000015;
276
        tau3 = 0.0000001;// 1.6MHz out of audible range for null impact
277
        i = 1. / (2. * M_PI * tau1);
278
        j = 1. / (2. * M_PI * tau2);
279
        k = 1. / (2. * M_PI * tau3);
280
        break;
281
1
    case 5: //"50µs FM (Europe)"
282
1
        tau1 = 0.000050;
283
1
        tau2 = tau1 / 20;// not used
284
1
        tau3 = tau1 / 50;//
285
1
        i = 1. / (2. * M_PI * tau1);
286
1
        j = 1. / (2. * M_PI * tau2);
287
1
        k = 1. / (2. * M_PI * tau3);
288
1
        break;
289
    case 6: //"75µs FM (US)"
290
        tau1 = 0.000075;
291
        tau2 = tau1 / 20;// not used
292
        tau3 = tau1 / 50;//
293
        i = 1. / (2. * M_PI * tau1);
294
        j = 1. / (2. * M_PI * tau2);
295
        k = 1. / (2. * M_PI * tau3);
296
        break;
297
    }
298
299
2
    i *= 2 * M_PI;
300
2
    j *= 2 * M_PI;
301
2
    k *= 2 * M_PI;
302
303
2
    t = 1. / sr;
304
305
    //swap a1 b1, a2 b2
306

2
    if (s->type == 7 || s->type == 8) {
307
1
        double tau = (s->type == 7 ? 0.000050 : 0.000075);
308
1
        double f = 1.0 / (2 * M_PI * tau);
309
1
        double nyq = sr * 0.5;
310
1
        double gain = sqrt(1.0 + nyq * nyq / (f * f)); // gain at Nyquist
311
1
        double cfreq = sqrt((gain - 1.0) * f * f); // frequency
312
1
        double q = 1.0;
313
314
1
        if (s->type == 8)
315
1
            q = pow((sr / 3269.0) + 19.5, -0.25); // somewhat poor curve-fit
316
1
        if (s->type == 7)
317
            q = pow((sr / 4750.0) + 19.5, -0.25);
318
1
        if (s->mode == 0)
319
1
            set_highshelf_rbj(&s->rc.r1, cfreq, q, 1. / gain, sr);
320
        else
321
            set_highshelf_rbj(&s->rc.r1, cfreq, q, gain, sr);
322
1
        s->rc.use_brickw = 0;
323
    } else {
324
1
        s->rc.use_brickw = 1;
325
1
        if (s->mode == 0) { // Reproduction
326
1
            g  = 1. / (4.+2.*i*t+2.*k*t+i*k*t*t);
327
1
            a0 = (2.*t+j*t*t)*g;
328
1
            a1 = (2.*j*t*t)*g;
329
1
            a2 = (-2.*t+j*t*t)*g;
330
1
            b1 = (-8.+2.*i*k*t*t)*g;
331
1
            b2 = (4.-2.*i*t-2.*k*t+i*k*t*t)*g;
332
        } else {  // Production
333
            g  = 1. / (2.*t+j*t*t);
334
            a0 = (4.+2.*i*t+2.*k*t+i*k*t*t)*g;
335
            a1 = (-8.+2.*i*k*t*t)*g;
336
            a2 = (4.-2.*i*t-2.*k*t+i*k*t*t)*g;
337
            b1 = (2.*j*t*t)*g;
338
            b2 = (-2.*t+j*t*t)*g;
339
        }
340
341
1
        coeffs.a0 = a0;
342
1
        coeffs.a1 = a1;
343
1
        coeffs.a2 = a2;
344
1
        coeffs.b1 = b1;
345
1
        coeffs.b2 = b2;
346
347
        // the coeffs above give non-normalized value, so it should be normalized to produce 0dB at 1 kHz
348
        // find actual gain
349
        // Note: for FM emphasis, use 100 Hz for normalization instead
350
1
        gain1kHz = freq_gain(&coeffs, 1000.0, sr);
351
        // divide one filter's x[n-m] coefficients by that value
352
1
        gc = 1.0 / gain1kHz;
353
1
        s->rc.r1.a0 = coeffs.a0 * gc;
354
1
        s->rc.r1.a1 = coeffs.a1 * gc;
355
1
        s->rc.r1.a2 = coeffs.a2 * gc;
356
1
        s->rc.r1.b1 = coeffs.b1;
357
1
        s->rc.r1.b2 = coeffs.b2;
358
    }
359
360
2
    cutfreq = FFMIN(0.45 * sr, 21000.);
361
2
    set_lp_rbj(&s->rc.brickw, cutfreq, 0.707, sr, 1.);
362
363
2
    return 0;
364
}
365
366
static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
367
                           char *res, int res_len, int flags)
368
{
369
    int ret;
370
371
    ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);
372
    if (ret < 0)
373
        return ret;
374
375
    return config_input(ctx->inputs[0]);
376
}
377
378
2
static av_cold void uninit(AVFilterContext *ctx)
379
{
380
2
    AudioEmphasisContext *s = ctx->priv;
381
382
2
    av_frame_free(&s->w);
383
2
}
384
385
static const AVFilterPad avfilter_af_aemphasis_inputs[] = {
386
    {
387
        .name         = "default",
388
        .type         = AVMEDIA_TYPE_AUDIO,
389
        .config_props = config_input,
390
        .filter_frame = filter_frame,
391
    },
392
    { NULL }
393
};
394
395
static const AVFilterPad avfilter_af_aemphasis_outputs[] = {
396
    {
397
        .name = "default",
398
        .type = AVMEDIA_TYPE_AUDIO,
399
    },
400
    { NULL }
401
};
402
403
AVFilter ff_af_aemphasis = {
404
    .name          = "aemphasis",
405
    .description   = NULL_IF_CONFIG_SMALL("Audio emphasis."),
406
    .priv_size     = sizeof(AudioEmphasisContext),
407
    .priv_class    = &aemphasis_class,
408
    .uninit        = uninit,
409
    .query_formats = query_formats,
410
    .inputs        = avfilter_af_aemphasis_inputs,
411
    .outputs       = avfilter_af_aemphasis_outputs,
412
    .process_command = process_command,
413
    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC |
414
                     AVFILTER_FLAG_SLICE_THREADS,
415
};