Merge commit '1173320249745eab01c901a39054fc0fced33c87'
[ffmpeg.git] / libavresample / utils.c
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 "libavutil/common.h"
22 #include "libavutil/dict.h"
23 // #include "libavutil/error.h"
24 #include "libavutil/log.h"
25 #include "libavutil/mem.h"
26 #include "libavutil/opt.h"
27
28 #include "avresample.h"
29 #include "internal.h"
30 #include "audio_data.h"
31 #include "audio_convert.h"
32 #include "audio_mix.h"
33 #include "resample.h"
34
35 int avresample_open(AVAudioResampleContext *avr)
36 {
37     int ret;
38
39     if (avresample_is_open(avr)) {
40         av_log(avr, AV_LOG_ERROR, "The resampling context is already open.\n");
41         return AVERROR(EINVAL);
42     }
43
44     /* set channel mixing parameters */
45     avr->in_channels = av_get_channel_layout_nb_channels(avr->in_channel_layout);
46     if (avr->in_channels <= 0 || avr->in_channels > AVRESAMPLE_MAX_CHANNELS) {
47         av_log(avr, AV_LOG_ERROR, "Invalid input channel layout: %"PRIu64"\n",
48                avr->in_channel_layout);
49         return AVERROR(EINVAL);
50     }
51     avr->out_channels = av_get_channel_layout_nb_channels(avr->out_channel_layout);
52     if (avr->out_channels <= 0 || avr->out_channels > AVRESAMPLE_MAX_CHANNELS) {
53         av_log(avr, AV_LOG_ERROR, "Invalid output channel layout: %"PRIu64"\n",
54                avr->out_channel_layout);
55         return AVERROR(EINVAL);
56     }
57     avr->resample_channels = FFMIN(avr->in_channels, avr->out_channels);
58     avr->downmix_needed    = avr->in_channels  > avr->out_channels;
59     avr->upmix_needed      = avr->out_channels > avr->in_channels ||
60                              (!avr->downmix_needed && (avr->mix_matrix ||
61                               avr->in_channel_layout != avr->out_channel_layout));
62     avr->mixing_needed     = avr->downmix_needed || avr->upmix_needed;
63
64     /* set resampling parameters */
65     avr->resample_needed   = avr->in_sample_rate != avr->out_sample_rate ||
66                              avr->force_resampling;
67
68     /* select internal sample format if not specified by the user */
69     if (avr->internal_sample_fmt == AV_SAMPLE_FMT_NONE &&
70         (avr->mixing_needed || avr->resample_needed)) {
71         enum AVSampleFormat  in_fmt = av_get_planar_sample_fmt(avr->in_sample_fmt);
72         enum AVSampleFormat out_fmt = av_get_planar_sample_fmt(avr->out_sample_fmt);
73         int max_bps = FFMAX(av_get_bytes_per_sample(in_fmt),
74                             av_get_bytes_per_sample(out_fmt));
75         if (max_bps <= 2) {
76             avr->internal_sample_fmt = AV_SAMPLE_FMT_S16P;
77         } else if (avr->mixing_needed) {
78             avr->internal_sample_fmt = AV_SAMPLE_FMT_FLTP;
79         } else {
80             if (max_bps <= 4) {
81                 if (in_fmt  == AV_SAMPLE_FMT_S32P ||
82                     out_fmt == AV_SAMPLE_FMT_S32P) {
83                     if (in_fmt  == AV_SAMPLE_FMT_FLTP ||
84                         out_fmt == AV_SAMPLE_FMT_FLTP) {
85                         /* if one is s32 and the other is flt, use dbl */
86                         avr->internal_sample_fmt = AV_SAMPLE_FMT_DBLP;
87                     } else {
88                         /* if one is s32 and the other is s32, s16, or u8, use s32 */
89                         avr->internal_sample_fmt = AV_SAMPLE_FMT_S32P;
90                     }
91                 } else {
92                     /* if one is flt and the other is flt, s16 or u8, use flt */
93                     avr->internal_sample_fmt = AV_SAMPLE_FMT_FLTP;
94                 }
95             } else {
96                 /* if either is dbl, use dbl */
97                 avr->internal_sample_fmt = AV_SAMPLE_FMT_DBLP;
98             }
99         }
100         av_log(avr, AV_LOG_DEBUG, "Using %s as internal sample format\n",
101                av_get_sample_fmt_name(avr->internal_sample_fmt));
102     }
103
104     /* treat all mono as planar for easier comparison */
105     if (avr->in_channels == 1)
106         avr->in_sample_fmt = av_get_planar_sample_fmt(avr->in_sample_fmt);
107     if (avr->out_channels == 1)
108         avr->out_sample_fmt = av_get_planar_sample_fmt(avr->out_sample_fmt);
109
110     /* we may need to add an extra conversion in order to remap channels if
111        the output format is not planar */
112     if (avr->use_channel_map && !avr->mixing_needed && !avr->resample_needed &&
113         !av_sample_fmt_is_planar(avr->out_sample_fmt)) {
114         avr->internal_sample_fmt = av_get_planar_sample_fmt(avr->out_sample_fmt);
115     }
116
117     /* set sample format conversion parameters */
118     if (avr->resample_needed || avr->mixing_needed)
119         avr->in_convert_needed = avr->in_sample_fmt != avr->internal_sample_fmt;
120     else
121         avr->in_convert_needed = avr->use_channel_map &&
122                                  !av_sample_fmt_is_planar(avr->out_sample_fmt);
123
124     if (avr->resample_needed || avr->mixing_needed || avr->in_convert_needed)
125         avr->out_convert_needed = avr->internal_sample_fmt != avr->out_sample_fmt;
126     else
127         avr->out_convert_needed = avr->in_sample_fmt != avr->out_sample_fmt;
128
129     avr->in_copy_needed = !avr->in_convert_needed && (avr->mixing_needed ||
130                           (avr->use_channel_map && avr->resample_needed));
131
132     if (avr->use_channel_map) {
133         if (avr->in_copy_needed) {
134             avr->remap_point = REMAP_IN_COPY;
135             av_dlog(avr, "remap channels during in_copy\n");
136         } else if (avr->in_convert_needed) {
137             avr->remap_point = REMAP_IN_CONVERT;
138             av_dlog(avr, "remap channels during in_convert\n");
139         } else if (avr->out_convert_needed) {
140             avr->remap_point = REMAP_OUT_CONVERT;
141             av_dlog(avr, "remap channels during out_convert\n");
142         } else {
143             avr->remap_point = REMAP_OUT_COPY;
144             av_dlog(avr, "remap channels during out_copy\n");
145         }
146
147 #ifdef DEBUG
148         {
149             int ch;
150             av_dlog(avr, "output map: ");
151             if (avr->ch_map_info.do_remap)
152                 for (ch = 0; ch < avr->in_channels; ch++)
153                     av_dlog(avr, " % 2d", avr->ch_map_info.channel_map[ch]);
154             else
155                 av_dlog(avr, "n/a");
156             av_dlog(avr, "\n");
157             av_dlog(avr, "copy map:   ");
158             if (avr->ch_map_info.do_copy)
159                 for (ch = 0; ch < avr->in_channels; ch++)
160                     av_dlog(avr, " % 2d", avr->ch_map_info.channel_copy[ch]);
161             else
162                 av_dlog(avr, "n/a");
163             av_dlog(avr, "\n");
164             av_dlog(avr, "zero map:   ");
165             if (avr->ch_map_info.do_zero)
166                 for (ch = 0; ch < avr->in_channels; ch++)
167                     av_dlog(avr, " % 2d", avr->ch_map_info.channel_zero[ch]);
168             else
169                 av_dlog(avr, "n/a");
170             av_dlog(avr, "\n");
171             av_dlog(avr, "input map:  ");
172             for (ch = 0; ch < avr->in_channels; ch++)
173                 av_dlog(avr, " % 2d", avr->ch_map_info.input_map[ch]);
174             av_dlog(avr, "\n");
175         }
176 #endif
177     } else
178         avr->remap_point = REMAP_NONE;
179
180     /* allocate buffers */
181     if (avr->in_copy_needed || avr->in_convert_needed) {
182         avr->in_buffer = ff_audio_data_alloc(FFMAX(avr->in_channels, avr->out_channels),
183                                              0, avr->internal_sample_fmt,
184                                              "in_buffer");
185         if (!avr->in_buffer) {
186             ret = AVERROR(EINVAL);
187             goto error;
188         }
189     }
190     if (avr->resample_needed) {
191         avr->resample_out_buffer = ff_audio_data_alloc(avr->out_channels,
192                                                        1024, avr->internal_sample_fmt,
193                                                        "resample_out_buffer");
194         if (!avr->resample_out_buffer) {
195             ret = AVERROR(EINVAL);
196             goto error;
197         }
198     }
199     if (avr->out_convert_needed) {
200         avr->out_buffer = ff_audio_data_alloc(avr->out_channels, 0,
201                                               avr->out_sample_fmt, "out_buffer");
202         if (!avr->out_buffer) {
203             ret = AVERROR(EINVAL);
204             goto error;
205         }
206     }
207     avr->out_fifo = av_audio_fifo_alloc(avr->out_sample_fmt, avr->out_channels,
208                                         1024);
209     if (!avr->out_fifo) {
210         ret = AVERROR(ENOMEM);
211         goto error;
212     }
213
214     /* setup contexts */
215     if (avr->in_convert_needed) {
216         avr->ac_in = ff_audio_convert_alloc(avr, avr->internal_sample_fmt,
217                                             avr->in_sample_fmt, avr->in_channels,
218                                             avr->in_sample_rate,
219                                             avr->remap_point == REMAP_IN_CONVERT);
220         if (!avr->ac_in) {
221             ret = AVERROR(ENOMEM);
222             goto error;
223         }
224     }
225     if (avr->out_convert_needed) {
226         enum AVSampleFormat src_fmt;
227         if (avr->in_convert_needed)
228             src_fmt = avr->internal_sample_fmt;
229         else
230             src_fmt = avr->in_sample_fmt;
231         avr->ac_out = ff_audio_convert_alloc(avr, avr->out_sample_fmt, src_fmt,
232                                              avr->out_channels,
233                                              avr->out_sample_rate,
234                                              avr->remap_point == REMAP_OUT_CONVERT);
235         if (!avr->ac_out) {
236             ret = AVERROR(ENOMEM);
237             goto error;
238         }
239     }
240     if (avr->resample_needed) {
241         avr->resample = ff_audio_resample_init(avr);
242         if (!avr->resample) {
243             ret = AVERROR(ENOMEM);
244             goto error;
245         }
246     }
247     if (avr->mixing_needed) {
248         avr->am = ff_audio_mix_alloc(avr);
249         if (!avr->am) {
250             ret = AVERROR(ENOMEM);
251             goto error;
252         }
253     }
254
255     return 0;
256
257 error:
258     avresample_close(avr);
259     return ret;
260 }
261
262 int avresample_is_open(AVAudioResampleContext *avr)
263 {
264     return !!avr->out_fifo;
265 }
266
267 void avresample_close(AVAudioResampleContext *avr)
268 {
269     ff_audio_data_free(&avr->in_buffer);
270     ff_audio_data_free(&avr->resample_out_buffer);
271     ff_audio_data_free(&avr->out_buffer);
272     av_audio_fifo_free(avr->out_fifo);
273     avr->out_fifo = NULL;
274     ff_audio_convert_free(&avr->ac_in);
275     ff_audio_convert_free(&avr->ac_out);
276     ff_audio_resample_free(&avr->resample);
277     ff_audio_mix_free(&avr->am);
278     av_freep(&avr->mix_matrix);
279
280     avr->use_channel_map = 0;
281 }
282
283 void avresample_free(AVAudioResampleContext **avr)
284 {
285     if (!*avr)
286         return;
287     avresample_close(*avr);
288     av_opt_free(*avr);
289     av_freep(avr);
290 }
291
292 static int handle_buffered_output(AVAudioResampleContext *avr,
293                                   AudioData *output, AudioData *converted)
294 {
295     int ret;
296
297     if (!output || av_audio_fifo_size(avr->out_fifo) > 0 ||
298         (converted && output->allocated_samples < converted->nb_samples)) {
299         if (converted) {
300             /* if there are any samples in the output FIFO or if the
301                user-supplied output buffer is not large enough for all samples,
302                we add to the output FIFO */
303             av_dlog(avr, "[FIFO] add %s to out_fifo\n", converted->name);
304             ret = ff_audio_data_add_to_fifo(avr->out_fifo, converted, 0,
305                                             converted->nb_samples);
306             if (ret < 0)
307                 return ret;
308         }
309
310         /* if the user specified an output buffer, read samples from the output
311            FIFO to the user output */
312         if (output && output->allocated_samples > 0) {
313             av_dlog(avr, "[FIFO] read from out_fifo to output\n");
314             av_dlog(avr, "[end conversion]\n");
315             return ff_audio_data_read_from_fifo(avr->out_fifo, output,
316                                                 output->allocated_samples);
317         }
318     } else if (converted) {
319         /* copy directly to output if it is large enough or there is not any
320            data in the output FIFO */
321         av_dlog(avr, "[copy] %s to output\n", converted->name);
322         output->nb_samples = 0;
323         ret = ff_audio_data_copy(output, converted,
324                                  avr->remap_point == REMAP_OUT_COPY ?
325                                  &avr->ch_map_info : NULL);
326         if (ret < 0)
327             return ret;
328         av_dlog(avr, "[end conversion]\n");
329         return output->nb_samples;
330     }
331     av_dlog(avr, "[end conversion]\n");
332     return 0;
333 }
334
335 int attribute_align_arg avresample_convert(AVAudioResampleContext *avr,
336                                            uint8_t **output, int out_plane_size,
337                                            int out_samples, uint8_t **input,
338                                            int in_plane_size, int in_samples)
339 {
340     AudioData input_buffer;
341     AudioData output_buffer;
342     AudioData *current_buffer;
343     int ret, direct_output;
344
345     /* reset internal buffers */
346     if (avr->in_buffer) {
347         avr->in_buffer->nb_samples = 0;
348         ff_audio_data_set_channels(avr->in_buffer,
349                                    avr->in_buffer->allocated_channels);
350     }
351     if (avr->resample_out_buffer) {
352         avr->resample_out_buffer->nb_samples = 0;
353         ff_audio_data_set_channels(avr->resample_out_buffer,
354                                    avr->resample_out_buffer->allocated_channels);
355     }
356     if (avr->out_buffer) {
357         avr->out_buffer->nb_samples = 0;
358         ff_audio_data_set_channels(avr->out_buffer,
359                                    avr->out_buffer->allocated_channels);
360     }
361
362     av_dlog(avr, "[start conversion]\n");
363
364     /* initialize output_buffer with output data */
365     direct_output = output && av_audio_fifo_size(avr->out_fifo) == 0;
366     if (output) {
367         ret = ff_audio_data_init(&output_buffer, output, out_plane_size,
368                                  avr->out_channels, out_samples,
369                                  avr->out_sample_fmt, 0, "output");
370         if (ret < 0)
371             return ret;
372         output_buffer.nb_samples = 0;
373     }
374
375     if (input) {
376         /* initialize input_buffer with input data */
377         ret = ff_audio_data_init(&input_buffer, input, in_plane_size,
378                                  avr->in_channels, in_samples,
379                                  avr->in_sample_fmt, 1, "input");
380         if (ret < 0)
381             return ret;
382         current_buffer = &input_buffer;
383
384         if (avr->upmix_needed && !avr->in_convert_needed && !avr->resample_needed &&
385             !avr->out_convert_needed && direct_output && out_samples >= in_samples) {
386             /* in some rare cases we can copy input to output and upmix
387                directly in the output buffer */
388             av_dlog(avr, "[copy] %s to output\n", current_buffer->name);
389             ret = ff_audio_data_copy(&output_buffer, current_buffer,
390                                      avr->remap_point == REMAP_OUT_COPY ?
391                                      &avr->ch_map_info : NULL);
392             if (ret < 0)
393                 return ret;
394             current_buffer = &output_buffer;
395         } else if (avr->remap_point == REMAP_OUT_COPY &&
396                    (!direct_output || out_samples < in_samples)) {
397             /* if remapping channels during output copy, we may need to
398              * use an intermediate buffer in order to remap before adding
399              * samples to the output fifo */
400             av_dlog(avr, "[copy] %s to out_buffer\n", current_buffer->name);
401             ret = ff_audio_data_copy(avr->out_buffer, current_buffer,
402                                      &avr->ch_map_info);
403             if (ret < 0)
404                 return ret;
405             current_buffer = avr->out_buffer;
406         } else if (avr->in_copy_needed || avr->in_convert_needed) {
407             /* if needed, copy or convert input to in_buffer, and downmix if
408                applicable */
409             if (avr->in_convert_needed) {
410                 ret = ff_audio_data_realloc(avr->in_buffer,
411                                             current_buffer->nb_samples);
412                 if (ret < 0)
413                     return ret;
414                 av_dlog(avr, "[convert] %s to in_buffer\n", current_buffer->name);
415                 ret = ff_audio_convert(avr->ac_in, avr->in_buffer,
416                                        current_buffer);
417                 if (ret < 0)
418                     return ret;
419             } else {
420                 av_dlog(avr, "[copy] %s to in_buffer\n", current_buffer->name);
421                 ret = ff_audio_data_copy(avr->in_buffer, current_buffer,
422                                          avr->remap_point == REMAP_IN_COPY ?
423                                          &avr->ch_map_info : NULL);
424                 if (ret < 0)
425                     return ret;
426             }
427             ff_audio_data_set_channels(avr->in_buffer, avr->in_channels);
428             if (avr->downmix_needed) {
429                 av_dlog(avr, "[downmix] in_buffer\n");
430                 ret = ff_audio_mix(avr->am, avr->in_buffer);
431                 if (ret < 0)
432                     return ret;
433             }
434             current_buffer = avr->in_buffer;
435         }
436     } else {
437         /* flush resampling buffer and/or output FIFO if input is NULL */
438         if (!avr->resample_needed)
439             return handle_buffered_output(avr, output ? &output_buffer : NULL,
440                                           NULL);
441         current_buffer = NULL;
442     }
443
444     if (avr->resample_needed) {
445         AudioData *resample_out;
446
447         if (!avr->out_convert_needed && direct_output && out_samples > 0)
448             resample_out = &output_buffer;
449         else
450             resample_out = avr->resample_out_buffer;
451         av_dlog(avr, "[resample] %s to %s\n",
452                 current_buffer ? current_buffer->name : "null",
453                 resample_out->name);
454         ret = ff_audio_resample(avr->resample, resample_out,
455                                 current_buffer);
456         if (ret < 0)
457             return ret;
458
459         /* if resampling did not produce any samples, just return 0 */
460         if (resample_out->nb_samples == 0) {
461             av_dlog(avr, "[end conversion]\n");
462             return 0;
463         }
464
465         current_buffer = resample_out;
466     }
467
468     if (avr->upmix_needed) {
469         av_dlog(avr, "[upmix] %s\n", current_buffer->name);
470         ret = ff_audio_mix(avr->am, current_buffer);
471         if (ret < 0)
472             return ret;
473     }
474
475     /* if we resampled or upmixed directly to output, return here */
476     if (current_buffer == &output_buffer) {
477         av_dlog(avr, "[end conversion]\n");
478         return current_buffer->nb_samples;
479     }
480
481     if (avr->out_convert_needed) {
482         if (direct_output && out_samples >= current_buffer->nb_samples) {
483             /* convert directly to output */
484             av_dlog(avr, "[convert] %s to output\n", current_buffer->name);
485             ret = ff_audio_convert(avr->ac_out, &output_buffer, current_buffer);
486             if (ret < 0)
487                 return ret;
488
489             av_dlog(avr, "[end conversion]\n");
490             return output_buffer.nb_samples;
491         } else {
492             ret = ff_audio_data_realloc(avr->out_buffer,
493                                         current_buffer->nb_samples);
494             if (ret < 0)
495                 return ret;
496             av_dlog(avr, "[convert] %s to out_buffer\n", current_buffer->name);
497             ret = ff_audio_convert(avr->ac_out, avr->out_buffer,
498                                    current_buffer);
499             if (ret < 0)
500                 return ret;
501             current_buffer = avr->out_buffer;
502         }
503     }
504
505     return handle_buffered_output(avr, output ? &output_buffer : NULL,
506                                   current_buffer);
507 }
508
509 int avresample_get_matrix(AVAudioResampleContext *avr, double *matrix,
510                           int stride)
511 {
512     int in_channels, out_channels, i, o;
513
514     if (avr->am)
515         return ff_audio_mix_get_matrix(avr->am, matrix, stride);
516
517     in_channels  = av_get_channel_layout_nb_channels(avr->in_channel_layout);
518     out_channels = av_get_channel_layout_nb_channels(avr->out_channel_layout);
519
520     if ( in_channels <= 0 ||  in_channels > AVRESAMPLE_MAX_CHANNELS ||
521         out_channels <= 0 || out_channels > AVRESAMPLE_MAX_CHANNELS) {
522         av_log(avr, AV_LOG_ERROR, "Invalid channel layouts\n");
523         return AVERROR(EINVAL);
524     }
525
526     if (!avr->mix_matrix) {
527         av_log(avr, AV_LOG_ERROR, "matrix is not set\n");
528         return AVERROR(EINVAL);
529     }
530
531     for (o = 0; o < out_channels; o++)
532         for (i = 0; i < in_channels; i++)
533             matrix[o * stride + i] = avr->mix_matrix[o * in_channels + i];
534
535     return 0;
536 }
537
538 int avresample_set_matrix(AVAudioResampleContext *avr, const double *matrix,
539                           int stride)
540 {
541     int in_channels, out_channels, i, o;
542
543     if (avr->am)
544         return ff_audio_mix_set_matrix(avr->am, matrix, stride);
545
546     in_channels  = av_get_channel_layout_nb_channels(avr->in_channel_layout);
547     out_channels = av_get_channel_layout_nb_channels(avr->out_channel_layout);
548
549     if ( in_channels <= 0 ||  in_channels > AVRESAMPLE_MAX_CHANNELS ||
550         out_channels <= 0 || out_channels > AVRESAMPLE_MAX_CHANNELS) {
551         av_log(avr, AV_LOG_ERROR, "Invalid channel layouts\n");
552         return AVERROR(EINVAL);
553     }
554
555     if (avr->mix_matrix)
556         av_freep(&avr->mix_matrix);
557     avr->mix_matrix = av_malloc(in_channels * out_channels *
558                                 sizeof(*avr->mix_matrix));
559     if (!avr->mix_matrix)
560         return AVERROR(ENOMEM);
561
562     for (o = 0; o < out_channels; o++)
563         for (i = 0; i < in_channels; i++)
564             avr->mix_matrix[o * in_channels + i] = matrix[o * stride + i];
565
566     return 0;
567 }
568
569 int avresample_set_channel_mapping(AVAudioResampleContext *avr,
570                                    const int *channel_map)
571 {
572     ChannelMapInfo *info = &avr->ch_map_info;
573     int in_channels, ch, i;
574
575     in_channels = av_get_channel_layout_nb_channels(avr->in_channel_layout);
576     if (in_channels <= 0 ||  in_channels > AVRESAMPLE_MAX_CHANNELS) {
577         av_log(avr, AV_LOG_ERROR, "Invalid input channel layout\n");
578         return AVERROR(EINVAL);
579     }
580
581     memset(info, 0, sizeof(*info));
582     memset(info->input_map, -1, sizeof(info->input_map));
583
584     for (ch = 0; ch < in_channels; ch++) {
585         if (channel_map[ch] >= in_channels) {
586             av_log(avr, AV_LOG_ERROR, "Invalid channel map\n");
587             return AVERROR(EINVAL);
588         }
589         if (channel_map[ch] < 0) {
590             info->channel_zero[ch] =  1;
591             info->channel_map[ch]  = -1;
592             info->do_zero          =  1;
593         } else if (info->input_map[channel_map[ch]] >= 0) {
594             info->channel_copy[ch] = info->input_map[channel_map[ch]];
595             info->channel_map[ch]  = -1;
596             info->do_copy          =  1;
597         } else {
598             info->channel_map[ch]            = channel_map[ch];
599             info->input_map[channel_map[ch]] = ch;
600             info->do_remap                   =  1;
601         }
602     }
603     /* Fill-in unmapped input channels with unmapped output channels.
604        This is used when remapping during conversion from interleaved to
605        planar format. */
606     for (ch = 0, i = 0; ch < in_channels && i < in_channels; ch++, i++) {
607         while (ch < in_channels && info->input_map[ch] >= 0)
608             ch++;
609         while (i < in_channels && info->channel_map[i] >= 0)
610             i++;
611         if (ch >= in_channels || i >= in_channels)
612             break;
613         info->input_map[ch] = i;
614     }
615
616     avr->use_channel_map = 1;
617     return 0;
618 }
619
620 int avresample_available(AVAudioResampleContext *avr)
621 {
622     return av_audio_fifo_size(avr->out_fifo);
623 }
624
625 int avresample_get_out_samples(AVAudioResampleContext *avr, int in_nb_samples)
626 {
627     int64_t samples = avresample_get_delay(avr) + (int64_t)in_nb_samples;
628
629     if (avr->resample_needed) {
630         samples = av_rescale_rnd(samples,
631                                  avr->out_sample_rate,
632                                  avr->in_sample_rate,
633                                  AV_ROUND_UP);
634     }
635
636     samples += avresample_available(avr);
637
638     if (samples > INT_MAX)
639         return AVERROR(EINVAL);
640
641     return samples;
642 }
643
644 int avresample_read(AVAudioResampleContext *avr, uint8_t **output, int nb_samples)
645 {
646     if (!output)
647         return av_audio_fifo_drain(avr->out_fifo, nb_samples);
648     return av_audio_fifo_read(avr->out_fifo, (void**)output, nb_samples);
649 }
650
651 unsigned avresample_version(void)
652 {
653     return LIBAVRESAMPLE_VERSION_INT;
654 }
655
656 const char *avresample_license(void)
657 {
658 #define LICENSE_PREFIX "libavresample license: "
659     return LICENSE_PREFIX FFMPEG_LICENSE + sizeof(LICENSE_PREFIX) - 1;
660 }
661
662 const char *avresample_configuration(void)
663 {
664     return FFMPEG_CONFIGURATION;
665 }