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audio_mix.c
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1 /*
2  * Copyright (c) 2012 Justin Ruggles <justin.ruggles@gmail.com>
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 <stdint.h>
22 
23 #include "libavutil/common.h"
24 #include "libavutil/libm.h"
25 #include "libavutil/samplefmt.h"
26 #include "avresample.h"
27 #include "internal.h"
28 #include "audio_data.h"
29 #include "audio_mix.h"
30 
31 static const char * const coeff_type_names[] = { "q8", "q15", "flt" };
32 
33 struct AudioMix {
37  uint64_t in_layout;
38  uint64_t out_layout;
41 
42  int ptr_align;
45  const char *func_descr;
46  const char *func_descr_generic;
49 
58  void **matrix;
59 };
60 
62  enum AVMixCoeffType coeff_type, int in_channels,
63  int out_channels, int ptr_align, int samples_align,
64  const char *descr, void *mix_func)
65 {
66  if (fmt == am->fmt && coeff_type == am->coeff_type &&
67  ( in_channels == am->in_matrix_channels || in_channels == 0) &&
68  (out_channels == am->out_matrix_channels || out_channels == 0)) {
69  char chan_str[16];
70  am->mix = mix_func;
71  am->func_descr = descr;
72  am->ptr_align = ptr_align;
73  am->samples_align = samples_align;
74  if (ptr_align == 1 && samples_align == 1) {
75  am->mix_generic = mix_func;
76  am->func_descr_generic = descr;
77  } else {
78  am->has_optimized_func = 1;
79  }
80  if (in_channels) {
81  if (out_channels)
82  snprintf(chan_str, sizeof(chan_str), "[%d to %d] ",
83  in_channels, out_channels);
84  else
85  snprintf(chan_str, sizeof(chan_str), "[%d to any] ",
86  in_channels);
87  } else if (out_channels) {
88  snprintf(chan_str, sizeof(chan_str), "[any to %d] ",
89  out_channels);
90  } else {
91  snprintf(chan_str, sizeof(chan_str), "[any to any] ");
92  }
93  av_log(am->avr, AV_LOG_DEBUG, "audio_mix: found function: [fmt=%s] "
94  "[c=%s] %s(%s)\n", av_get_sample_fmt_name(fmt),
95  coeff_type_names[coeff_type], chan_str, descr);
96  }
97 }
98 
99 #define MIX_FUNC_NAME(fmt, cfmt) mix_any_ ## fmt ##_## cfmt ##_c
100 
101 #define MIX_FUNC_GENERIC(fmt, cfmt, stype, ctype, sumtype, expr) \
102 static void MIX_FUNC_NAME(fmt, cfmt)(stype **samples, ctype **matrix, \
103  int len, int out_ch, int in_ch) \
104 { \
105  int i, in, out; \
106  stype temp[AVRESAMPLE_MAX_CHANNELS]; \
107  for (i = 0; i < len; i++) { \
108  for (out = 0; out < out_ch; out++) { \
109  sumtype sum = 0; \
110  for (in = 0; in < in_ch; in++) \
111  sum += samples[in][i] * matrix[out][in]; \
112  temp[out] = expr; \
113  } \
114  for (out = 0; out < out_ch; out++) \
115  samples[out][i] = temp[out]; \
116  } \
117 }
118 
119 MIX_FUNC_GENERIC(FLTP, FLT, float, float, float, sum)
120 MIX_FUNC_GENERIC(S16P, FLT, int16_t, float, float, av_clip_int16(lrintf(sum)))
121 MIX_FUNC_GENERIC(S16P, Q15, int16_t, int32_t, int64_t, av_clip_int16(sum >> 15))
122 MIX_FUNC_GENERIC(S16P, Q8, int16_t, int16_t, int32_t, av_clip_int16(sum >> 8))
123 
124 /* TODO: templatize the channel-specific C functions */
125 
126 static void mix_2_to_1_fltp_flt_c(float **samples, float **matrix, int len,
127  int out_ch, int in_ch)
128 {
129  float *src0 = samples[0];
130  float *src1 = samples[1];
131  float *dst = src0;
132  float m0 = matrix[0][0];
133  float m1 = matrix[0][1];
134 
135  while (len > 4) {
136  *dst++ = *src0++ * m0 + *src1++ * m1;
137  *dst++ = *src0++ * m0 + *src1++ * m1;
138  *dst++ = *src0++ * m0 + *src1++ * m1;
139  *dst++ = *src0++ * m0 + *src1++ * m1;
140  len -= 4;
141  }
142  while (len > 0) {
143  *dst++ = *src0++ * m0 + *src1++ * m1;
144  len--;
145  }
146 }
147 
148 static void mix_2_to_1_s16p_flt_c(int16_t **samples, float **matrix, int len,
149  int out_ch, int in_ch)
150 {
151  int16_t *src0 = samples[0];
152  int16_t *src1 = samples[1];
153  int16_t *dst = src0;
154  float m0 = matrix[0][0];
155  float m1 = matrix[0][1];
156 
157  while (len > 4) {
158  *dst++ = av_clip_int16(lrintf(*src0++ * m0 + *src1++ * m1));
159  *dst++ = av_clip_int16(lrintf(*src0++ * m0 + *src1++ * m1));
160  *dst++ = av_clip_int16(lrintf(*src0++ * m0 + *src1++ * m1));
161  *dst++ = av_clip_int16(lrintf(*src0++ * m0 + *src1++ * m1));
162  len -= 4;
163  }
164  while (len > 0) {
165  *dst++ = av_clip_int16(lrintf(*src0++ * m0 + *src1++ * m1));
166  len--;
167  }
168 }
169 
170 static void mix_2_to_1_s16p_q8_c(int16_t **samples, int16_t **matrix, int len,
171  int out_ch, int in_ch)
172 {
173  int16_t *src0 = samples[0];
174  int16_t *src1 = samples[1];
175  int16_t *dst = src0;
176  int16_t m0 = matrix[0][0];
177  int16_t m1 = matrix[0][1];
178 
179  while (len > 4) {
180  *dst++ = (*src0++ * m0 + *src1++ * m1) >> 8;
181  *dst++ = (*src0++ * m0 + *src1++ * m1) >> 8;
182  *dst++ = (*src0++ * m0 + *src1++ * m1) >> 8;
183  *dst++ = (*src0++ * m0 + *src1++ * m1) >> 8;
184  len -= 4;
185  }
186  while (len > 0) {
187  *dst++ = (*src0++ * m0 + *src1++ * m1) >> 8;
188  len--;
189  }
190 }
191 
192 static void mix_1_to_2_fltp_flt_c(float **samples, float **matrix, int len,
193  int out_ch, int in_ch)
194 {
195  float v;
196  float *dst0 = samples[0];
197  float *dst1 = samples[1];
198  float *src = dst0;
199  float m0 = matrix[0][0];
200  float m1 = matrix[1][0];
201 
202  while (len > 4) {
203  v = *src++;
204  *dst0++ = v * m0;
205  *dst1++ = v * m1;
206  v = *src++;
207  *dst0++ = v * m0;
208  *dst1++ = v * m1;
209  v = *src++;
210  *dst0++ = v * m0;
211  *dst1++ = v * m1;
212  v = *src++;
213  *dst0++ = v * m0;
214  *dst1++ = v * m1;
215  len -= 4;
216  }
217  while (len > 0) {
218  v = *src++;
219  *dst0++ = v * m0;
220  *dst1++ = v * m1;
221  len--;
222  }
223 }
224 
225 static void mix_6_to_2_fltp_flt_c(float **samples, float **matrix, int len,
226  int out_ch, int in_ch)
227 {
228  float v0, v1;
229  float *src0 = samples[0];
230  float *src1 = samples[1];
231  float *src2 = samples[2];
232  float *src3 = samples[3];
233  float *src4 = samples[4];
234  float *src5 = samples[5];
235  float *dst0 = src0;
236  float *dst1 = src1;
237  float *m0 = matrix[0];
238  float *m1 = matrix[1];
239 
240  while (len > 0) {
241  v0 = *src0++;
242  v1 = *src1++;
243  *dst0++ = v0 * m0[0] +
244  v1 * m0[1] +
245  *src2 * m0[2] +
246  *src3 * m0[3] +
247  *src4 * m0[4] +
248  *src5 * m0[5];
249  *dst1++ = v0 * m1[0] +
250  v1 * m1[1] +
251  *src2++ * m1[2] +
252  *src3++ * m1[3] +
253  *src4++ * m1[4] +
254  *src5++ * m1[5];
255  len--;
256  }
257 }
258 
259 static void mix_2_to_6_fltp_flt_c(float **samples, float **matrix, int len,
260  int out_ch, int in_ch)
261 {
262  float v0, v1;
263  float *dst0 = samples[0];
264  float *dst1 = samples[1];
265  float *dst2 = samples[2];
266  float *dst3 = samples[3];
267  float *dst4 = samples[4];
268  float *dst5 = samples[5];
269  float *src0 = dst0;
270  float *src1 = dst1;
271 
272  while (len > 0) {
273  v0 = *src0++;
274  v1 = *src1++;
275  *dst0++ = v0 * matrix[0][0] + v1 * matrix[0][1];
276  *dst1++ = v0 * matrix[1][0] + v1 * matrix[1][1];
277  *dst2++ = v0 * matrix[2][0] + v1 * matrix[2][1];
278  *dst3++ = v0 * matrix[3][0] + v1 * matrix[3][1];
279  *dst4++ = v0 * matrix[4][0] + v1 * matrix[4][1];
280  *dst5++ = v0 * matrix[5][0] + v1 * matrix[5][1];
281  len--;
282  }
283 }
284 
286 {
287  am->func_descr = am->func_descr_generic = "n/a";
288  am->mix = am->mix_generic = NULL;
289 
290  /* no need to set a mix function when we're skipping mixing */
291  if (!am->in_matrix_channels || !am->out_matrix_channels)
292  return 0;
293 
294  /* any-to-any C versions */
295 
297  0, 0, 1, 1, "C", MIX_FUNC_NAME(FLTP, FLT));
298 
300  0, 0, 1, 1, "C", MIX_FUNC_NAME(S16P, FLT));
301 
303  0, 0, 1, 1, "C", MIX_FUNC_NAME(S16P, Q15));
304 
306  0, 0, 1, 1, "C", MIX_FUNC_NAME(S16P, Q8));
307 
308  /* channel-specific C versions */
309 
311  2, 1, 1, 1, "C", mix_2_to_1_fltp_flt_c);
312 
314  2, 1, 1, 1, "C", mix_2_to_1_s16p_flt_c);
315 
317  2, 1, 1, 1, "C", mix_2_to_1_s16p_q8_c);
318 
320  1, 2, 1, 1, "C", mix_1_to_2_fltp_flt_c);
321 
323  6, 2, 1, 1, "C", mix_6_to_2_fltp_flt_c);
324 
326  2, 6, 1, 1, "C", mix_2_to_6_fltp_flt_c);
327 
328  if (ARCH_X86)
330 
331  if (!am->mix) {
332  av_log(am->avr, AV_LOG_ERROR, "audio_mix: NO FUNCTION FOUND: [fmt=%s] "
333  "[c=%s] [%d to %d]\n", av_get_sample_fmt_name(am->fmt),
335  am->out_channels);
336  return AVERROR_PATCHWELCOME;
337  }
338  return 0;
339 }
340 
342 {
343  AudioMix *am;
344  int ret;
345 
346  am = av_mallocz(sizeof(*am));
347  if (!am)
348  return NULL;
349  am->avr = avr;
350 
353  av_log(avr, AV_LOG_ERROR, "Unsupported internal format for "
354  "mixing: %s\n",
356  goto error;
357  }
358 
359  am->fmt = avr->internal_sample_fmt;
360  am->coeff_type = avr->mix_coeff_type;
361  am->in_layout = avr->in_channel_layout;
362  am->out_layout = avr->out_channel_layout;
363  am->in_channels = avr->in_channels;
364  am->out_channels = avr->out_channels;
365 
366  /* build matrix if the user did not already set one */
367  if (avr->mix_matrix) {
368  ret = ff_audio_mix_set_matrix(am, avr->mix_matrix, avr->in_channels);
369  if (ret < 0)
370  goto error;
371  av_freep(&avr->mix_matrix);
372  } else {
373  double *matrix_dbl = av_mallocz(avr->out_channels * avr->in_channels *
374  sizeof(*matrix_dbl));
375  if (!matrix_dbl)
376  goto error;
377 
379  avr->out_channel_layout,
380  avr->center_mix_level,
381  avr->surround_mix_level,
382  avr->lfe_mix_level,
383  avr->normalize_mix_level,
384  matrix_dbl,
385  avr->in_channels,
386  avr->matrix_encoding);
387  if (ret < 0) {
388  av_free(matrix_dbl);
389  goto error;
390  }
391 
392  ret = ff_audio_mix_set_matrix(am, matrix_dbl, avr->in_channels);
393  if (ret < 0) {
394  av_log(avr, AV_LOG_ERROR, "error setting mix matrix\n");
395  av_free(matrix_dbl);
396  goto error;
397  }
398 
399  av_free(matrix_dbl);
400  }
401 
402  return am;
403 
404 error:
405  av_free(am);
406  return NULL;
407 }
408 
410 {
411  AudioMix *am;
412 
413  if (!*am_p)
414  return;
415  am = *am_p;
416 
417  if (am->matrix) {
418  av_free(am->matrix[0]);
419  am->matrix = NULL;
420  }
421  memset(am->matrix_q8, 0, sizeof(am->matrix_q8 ));
422  memset(am->matrix_q15, 0, sizeof(am->matrix_q15));
423  memset(am->matrix_flt, 0, sizeof(am->matrix_flt));
424 
425  av_freep(am_p);
426 }
427 
429 {
430  int use_generic = 1;
431  int len = src->nb_samples;
432  int i, j;
433 
434  /* determine whether to use the optimized function based on pointer and
435  samples alignment in both the input and output */
436  if (am->has_optimized_func) {
437  int aligned_len = FFALIGN(len, am->samples_align);
438  if (!(src->ptr_align % am->ptr_align) &&
439  src->samples_align >= aligned_len) {
440  len = aligned_len;
441  use_generic = 0;
442  }
443  }
444  av_log(am->avr, AV_LOG_TRACE, "audio_mix: %d samples - %d to %d channels (%s)\n",
445  src->nb_samples, am->in_channels, am->out_channels,
446  use_generic ? am->func_descr_generic : am->func_descr);
447 
448  if (am->in_matrix_channels && am->out_matrix_channels) {
449  uint8_t **data;
450  uint8_t *data0[AVRESAMPLE_MAX_CHANNELS] = { NULL };
451 
452  if (am->out_matrix_channels < am->out_channels ||
453  am->in_matrix_channels < am->in_channels) {
454  for (i = 0, j = 0; i < FFMAX(am->in_channels, am->out_channels); i++) {
455  if (am->input_skip[i] || am->output_skip[i] || am->output_zero[i])
456  continue;
457  data0[j++] = src->data[i];
458  }
459  data = data0;
460  } else {
461  data = src->data;
462  }
463 
464  if (use_generic)
465  am->mix_generic(data, am->matrix, len, am->out_matrix_channels,
466  am->in_matrix_channels);
467  else
468  am->mix(data, am->matrix, len, am->out_matrix_channels,
469  am->in_matrix_channels);
470  }
471 
472  if (am->out_matrix_channels < am->out_channels) {
473  for (i = 0; i < am->out_channels; i++)
474  if (am->output_zero[i])
475  av_samples_set_silence(&src->data[i], 0, len, 1, am->fmt);
476  }
477 
479 
480  return 0;
481 }
482 
483 int ff_audio_mix_get_matrix(AudioMix *am, double *matrix, int stride)
484 {
485  int i, o, i0, o0;
486 
487  if ( am->in_channels <= 0 || am->in_channels > AVRESAMPLE_MAX_CHANNELS ||
489  av_log(am->avr, AV_LOG_ERROR, "Invalid channel counts\n");
490  return AVERROR(EINVAL);
491  }
492 
493 #define GET_MATRIX_CONVERT(suffix, scale) \
494  if (!am->matrix_ ## suffix[0]) { \
495  av_log(am->avr, AV_LOG_ERROR, "matrix is not set\n"); \
496  return AVERROR(EINVAL); \
497  } \
498  for (o = 0, o0 = 0; o < am->out_channels; o++) { \
499  for (i = 0, i0 = 0; i < am->in_channels; i++) { \
500  if (am->input_skip[i] || am->output_zero[o]) \
501  matrix[o * stride + i] = 0.0; \
502  else \
503  matrix[o * stride + i] = am->matrix_ ## suffix[o0][i0] * \
504  (scale); \
505  if (!am->input_skip[i]) \
506  i0++; \
507  } \
508  if (!am->output_zero[o]) \
509  o0++; \
510  }
511 
512  switch (am->coeff_type) {
514  GET_MATRIX_CONVERT(q8, 1.0 / 256.0);
515  break;
517  GET_MATRIX_CONVERT(q15, 1.0 / 32768.0);
518  break;
520  GET_MATRIX_CONVERT(flt, 1.0);
521  break;
522  default:
523  av_log(am->avr, AV_LOG_ERROR, "Invalid mix coeff type\n");
524  return AVERROR(EINVAL);
525  }
526 
527  return 0;
528 }
529 
530 static void reduce_matrix(AudioMix *am, const double *matrix, int stride)
531 {
532  int i, o;
533 
534  memset(am->output_zero, 0, sizeof(am->output_zero));
535  memset(am->input_skip, 0, sizeof(am->input_skip));
536  memset(am->output_skip, 0, sizeof(am->output_skip));
537 
538  /* exclude output channels if they can be zeroed instead of mixed */
539  for (o = 0; o < am->out_channels; o++) {
540  int zero = 1;
541 
542  /* check if the output is always silent */
543  for (i = 0; i < am->in_channels; i++) {
544  if (matrix[o * stride + i] != 0.0) {
545  zero = 0;
546  break;
547  }
548  }
549  /* check if the corresponding input channel makes a contribution to
550  any output channel */
551  if (o < am->in_channels) {
552  for (i = 0; i < am->out_channels; i++) {
553  if (matrix[i * stride + o] != 0.0) {
554  zero = 0;
555  break;
556  }
557  }
558  }
559  if (zero) {
560  am->output_zero[o] = 1;
561  am->out_matrix_channels--;
562  if (o < am->in_channels)
563  am->in_matrix_channels--;
564  }
565  }
566  if (am->out_matrix_channels == 0 || am->in_matrix_channels == 0) {
567  am->out_matrix_channels = 0;
568  am->in_matrix_channels = 0;
569  return;
570  }
571 
572  /* skip input channels that contribute fully only to the corresponding
573  output channel */
574  for (i = 0; i < FFMIN(am->in_channels, am->out_channels); i++) {
575  int skip = 1;
576 
577  for (o = 0; o < am->out_channels; o++) {
578  int i0;
579  if ((o != i && matrix[o * stride + i] != 0.0) ||
580  (o == i && matrix[o * stride + i] != 1.0)) {
581  skip = 0;
582  break;
583  }
584  /* if the input contributes fully to the output, also check that no
585  other inputs contribute to this output */
586  if (o == i) {
587  for (i0 = 0; i0 < am->in_channels; i0++) {
588  if (i0 != i && matrix[o * stride + i0] != 0.0) {
589  skip = 0;
590  break;
591  }
592  }
593  }
594  }
595  if (skip) {
596  am->input_skip[i] = 1;
597  am->in_matrix_channels--;
598  }
599  }
600  /* skip input channels that do not contribute to any output channel */
601  for (; i < am->in_channels; i++) {
602  int contrib = 0;
603 
604  for (o = 0; o < am->out_channels; o++) {
605  if (matrix[o * stride + i] != 0.0) {
606  contrib = 1;
607  break;
608  }
609  }
610  if (!contrib) {
611  am->input_skip[i] = 1;
612  am->in_matrix_channels--;
613  }
614  }
615  if (am->in_matrix_channels == 0) {
616  am->out_matrix_channels = 0;
617  return;
618  }
619 
620  /* skip output channels that only get full contribution from the
621  corresponding input channel */
622  for (o = 0; o < FFMIN(am->in_channels, am->out_channels); o++) {
623  int skip = 1;
624  int o0;
625 
626  for (i = 0; i < am->in_channels; i++) {
627  if ((o != i && matrix[o * stride + i] != 0.0) ||
628  (o == i && matrix[o * stride + i] != 1.0)) {
629  skip = 0;
630  break;
631  }
632  }
633  /* check if the corresponding input channel makes a contribution to
634  any other output channel */
635  i = o;
636  for (o0 = 0; o0 < am->out_channels; o0++) {
637  if (o0 != i && matrix[o0 * stride + i] != 0.0) {
638  skip = 0;
639  break;
640  }
641  }
642  if (skip) {
643  am->output_skip[o] = 1;
644  am->out_matrix_channels--;
645  }
646  }
647  if (am->out_matrix_channels == 0) {
648  am->in_matrix_channels = 0;
649  return;
650  }
651 }
652 
653 int ff_audio_mix_set_matrix(AudioMix *am, const double *matrix, int stride)
654 {
655  int i, o, i0, o0, ret;
656  char in_layout_name[128];
657  char out_layout_name[128];
658 
659  if ( am->in_channels <= 0 || am->in_channels > AVRESAMPLE_MAX_CHANNELS ||
661  av_log(am->avr, AV_LOG_ERROR, "Invalid channel counts\n");
662  return AVERROR(EINVAL);
663  }
664 
665  if (am->matrix) {
666  av_free(am->matrix[0]);
667  am->matrix = NULL;
668  }
669 
672 
673  reduce_matrix(am, matrix, stride);
674 
675 #define CONVERT_MATRIX(type, expr) \
676  am->matrix_## type[0] = av_mallocz(am->out_matrix_channels * \
677  am->in_matrix_channels * \
678  sizeof(*am->matrix_## type[0])); \
679  if (!am->matrix_## type[0]) \
680  return AVERROR(ENOMEM); \
681  for (o = 0, o0 = 0; o < am->out_channels; o++) { \
682  if (am->output_zero[o] || am->output_skip[o]) \
683  continue; \
684  if (o0 > 0) \
685  am->matrix_## type[o0] = am->matrix_## type[o0 - 1] + \
686  am->in_matrix_channels; \
687  for (i = 0, i0 = 0; i < am->in_channels; i++) { \
688  double v; \
689  if (am->input_skip[i] || am->output_zero[i]) \
690  continue; \
691  v = matrix[o * stride + i]; \
692  am->matrix_## type[o0][i0] = expr; \
693  i0++; \
694  } \
695  o0++; \
696  } \
697  am->matrix = (void **)am->matrix_## type;
698 
699  if (am->in_matrix_channels && am->out_matrix_channels) {
700  switch (am->coeff_type) {
702  CONVERT_MATRIX(q8, av_clip_int16(lrint(256.0 * v)))
703  break;
705  CONVERT_MATRIX(q15, av_clipl_int32(llrint(32768.0 * v)))
706  break;
708  CONVERT_MATRIX(flt, v)
709  break;
710  default:
711  av_log(am->avr, AV_LOG_ERROR, "Invalid mix coeff type\n");
712  return AVERROR(EINVAL);
713  }
714  }
715 
716  ret = mix_function_init(am);
717  if (ret < 0)
718  return ret;
719 
720  av_get_channel_layout_string(in_layout_name, sizeof(in_layout_name),
721  am->in_channels, am->in_layout);
722  av_get_channel_layout_string(out_layout_name, sizeof(out_layout_name),
723  am->out_channels, am->out_layout);
724  av_log(am->avr, AV_LOG_DEBUG, "audio_mix: %s to %s\n",
725  in_layout_name, out_layout_name);
726  av_log(am->avr, AV_LOG_DEBUG, "matrix size: %d x %d\n",
728  for (o = 0; o < am->out_channels; o++) {
729  for (i = 0; i < am->in_channels; i++) {
730  if (am->output_zero[o])
731  av_log(am->avr, AV_LOG_DEBUG, " (ZERO)");
732  else if (am->input_skip[i] || am->output_zero[i] || am->output_skip[o])
733  av_log(am->avr, AV_LOG_DEBUG, " (SKIP)");
734  else
735  av_log(am->avr, AV_LOG_DEBUG, " %0.3f ",
736  matrix[o * am->in_channels + i]);
737  }
738  av_log(am->avr, AV_LOG_DEBUG, "\n");
739  }
740 
741  return 0;
742 }