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af_pan.c
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1 /*
2  * Copyright (c) 2002 Anders Johansson <ajh@atri.curtin.edu.au>
3  * Copyright (c) 2011 Clément Bœsch <u pkh me>
4  * Copyright (c) 2011 Nicolas George <nicolas.george@normalesup.org>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 /**
24  * @file
25  * Audio panning filter (channels mixing)
26  * Original code written by Anders Johansson for MPlayer,
27  * reimplemented for FFmpeg.
28  */
29 
30 #include <stdio.h>
31 #include "libavutil/avstring.h"
33 #include "libavutil/opt.h"
35 #include "audio.h"
36 #include "avfilter.h"
37 #include "formats.h"
38 #include "internal.h"
39 
40 #define MAX_CHANNELS 64
41 
42 typedef struct PanContext {
43  const AVClass *class;
44  char *args;
47  int64_t need_renorm;
50 
52  /* channel mapping specific */
54  struct SwrContext *swr;
55 } PanContext;
56 
57 static void skip_spaces(char **arg)
58 {
59  int len = 0;
60 
61  sscanf(*arg, " %n", &len);
62  *arg += len;
63 }
64 
65 static int parse_channel_name(char **arg, int *rchannel, int *rnamed)
66 {
67  char buf[8];
68  int len, i, channel_id = 0;
69  int64_t layout, layout0;
70 
71  skip_spaces(arg);
72  /* try to parse a channel name, e.g. "FL" */
73  if (sscanf(*arg, "%7[A-Z]%n", buf, &len)) {
74  layout0 = layout = av_get_channel_layout(buf);
75  /* channel_id <- first set bit in layout */
76  for (i = 32; i > 0; i >>= 1) {
77  if (layout >= (int64_t)1 << i) {
78  channel_id += i;
79  layout >>= i;
80  }
81  }
82  /* reject layouts that are not a single channel */
83  if (channel_id >= MAX_CHANNELS || layout0 != (int64_t)1 << channel_id)
84  return AVERROR(EINVAL);
85  *rchannel = channel_id;
86  *rnamed = 1;
87  *arg += len;
88  return 0;
89  }
90  /* try to parse a channel number, e.g. "c2" */
91  if (sscanf(*arg, "c%d%n", &channel_id, &len) &&
92  channel_id >= 0 && channel_id < MAX_CHANNELS) {
93  *rchannel = channel_id;
94  *rnamed = 0;
95  *arg += len;
96  return 0;
97  }
98  return AVERROR(EINVAL);
99 }
100 
102 {
103  PanContext *const pan = ctx->priv;
104  char *arg, *arg0, *tokenizer, *args = av_strdup(pan->args);
105  int out_ch_id, in_ch_id, len, named, ret, sign = 1;
106  int nb_in_channels[2] = { 0, 0 }; // number of unnamed and named input channels
107  double gain;
108 
109  if (!pan->args) {
110  av_log(ctx, AV_LOG_ERROR,
111  "pan filter needs a channel layout and a set "
112  "of channel definitions as parameter\n");
113  return AVERROR(EINVAL);
114  }
115  if (!args)
116  return AVERROR(ENOMEM);
117  arg = av_strtok(args, "|", &tokenizer);
118  if (!arg) {
119  av_log(ctx, AV_LOG_ERROR, "Channel layout not specified\n");
120  ret = AVERROR(EINVAL);
121  goto fail;
122  }
124  &pan->nb_output_channels, arg, ctx);
125  if (ret < 0)
126  goto fail;
127 
128  /* parse channel specifications */
129  while ((arg = arg0 = av_strtok(NULL, "|", &tokenizer))) {
130  /* channel name */
131  if (parse_channel_name(&arg, &out_ch_id, &named)) {
132  av_log(ctx, AV_LOG_ERROR,
133  "Expected out channel name, got \"%.8s\"\n", arg);
134  ret = AVERROR(EINVAL);
135  goto fail;
136  }
137  if (named) {
138  if (!((pan->out_channel_layout >> out_ch_id) & 1)) {
139  av_log(ctx, AV_LOG_ERROR,
140  "Channel \"%.8s\" does not exist in the chosen layout\n", arg0);
141  ret = AVERROR(EINVAL);
142  goto fail;
143  }
144  /* get the channel number in the output channel layout:
145  * out_channel_layout & ((1 << out_ch_id) - 1) are all the
146  * channels that come before out_ch_id,
147  * so their count is the index of out_ch_id */
148  out_ch_id = av_get_channel_layout_nb_channels(pan->out_channel_layout & (((int64_t)1 << out_ch_id) - 1));
149  }
150  if (out_ch_id < 0 || out_ch_id >= pan->nb_output_channels) {
151  av_log(ctx, AV_LOG_ERROR,
152  "Invalid out channel name \"%.8s\"\n", arg0);
153  ret = AVERROR(EINVAL);
154  goto fail;
155  }
156  skip_spaces(&arg);
157  if (*arg == '=') {
158  arg++;
159  } else if (*arg == '<') {
160  pan->need_renorm |= (int64_t)1 << out_ch_id;
161  arg++;
162  } else {
163  av_log(ctx, AV_LOG_ERROR,
164  "Syntax error after channel name in \"%.8s\"\n", arg0);
165  ret = AVERROR(EINVAL);
166  goto fail;
167  }
168  /* gains */
169  sign = 1;
170  while (1) {
171  gain = 1;
172  if (sscanf(arg, "%lf%n *%n", &gain, &len, &len))
173  arg += len;
174  if (parse_channel_name(&arg, &in_ch_id, &named)){
175  av_log(ctx, AV_LOG_ERROR,
176  "Expected in channel name, got \"%.8s\"\n", arg);
177  ret = AVERROR(EINVAL);
178  goto fail;
179  }
180  nb_in_channels[named]++;
181  if (nb_in_channels[!named]) {
182  av_log(ctx, AV_LOG_ERROR,
183  "Can not mix named and numbered channels\n");
184  ret = AVERROR(EINVAL);
185  goto fail;
186  }
187  pan->gain[out_ch_id][in_ch_id] = sign * gain;
188  skip_spaces(&arg);
189  if (!*arg)
190  break;
191  if (*arg == '-') {
192  sign = -1;
193  } else if (*arg != '+') {
194  av_log(ctx, AV_LOG_ERROR, "Syntax error near \"%.8s\"\n", arg);
195  ret = AVERROR(EINVAL);
196  goto fail;
197  } else {
198  sign = 1;
199  }
200  arg++;
201  }
202  }
203  pan->need_renumber = !!nb_in_channels[1];
204 
205  ret = 0;
206 fail:
207  av_free(args);
208  return ret;
209 }
210 
211 static int are_gains_pure(const PanContext *pan)
212 {
213  int i, j;
214 
215  for (i = 0; i < MAX_CHANNELS; i++) {
216  int nb_gain = 0;
217 
218  for (j = 0; j < MAX_CHANNELS; j++) {
219  double gain = pan->gain[i][j];
220 
221  /* channel mapping is effective only if 0% or 100% of a channel is
222  * selected... */
223  if (gain != 0. && gain != 1.)
224  return 0;
225  /* ...and if the output channel is only composed of one input */
226  if (gain && nb_gain++)
227  return 0;
228  }
229  }
230  return 1;
231 }
232 
234 {
235  PanContext *pan = ctx->priv;
236  AVFilterLink *inlink = ctx->inputs[0];
237  AVFilterLink *outlink = ctx->outputs[0];
240  int ret;
241 
242  pan->pure_gains = are_gains_pure(pan);
243  /* libswr supports any sample and packing formats */
245  return ret;
246 
247  formats = ff_all_samplerates();
248  if ((ret = ff_set_common_samplerates(ctx, formats)) < 0)
249  return ret;
250 
251  // inlink supports any channel layout
252  layouts = ff_all_channel_counts();
253  if ((ret = ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts)) < 0)
254  return ret;
255 
256  // outlink supports only requested output channel layout
257  layouts = NULL;
258  if ((ret = ff_add_channel_layout(&layouts,
261  return ret;
262  return ff_channel_layouts_ref(layouts, &outlink->in_channel_layouts);
263 }
264 
265 static int config_props(AVFilterLink *link)
266 {
267  AVFilterContext *ctx = link->dst;
268  PanContext *pan = ctx->priv;
269  char buf[1024], *cur;
270  int i, j, k, r;
271  double t;
272 
273  if (pan->need_renumber) {
274  // input channels were given by their name: renumber them
275  for (i = j = 0; i < MAX_CHANNELS; i++) {
276  if ((link->channel_layout >> i) & 1) {
277  for (k = 0; k < pan->nb_output_channels; k++)
278  pan->gain[k][j] = pan->gain[k][i];
279  j++;
280  }
281  }
282  }
283 
284  // sanity check; can't be done in query_formats since the inlink
285  // channel layout is unknown at that time
286  if (link->channels > MAX_CHANNELS ||
288  av_log(ctx, AV_LOG_ERROR,
289  "af_pan supports a maximum of %d channels. "
290  "Feel free to ask for a higher limit.\n", MAX_CHANNELS);
291  return AVERROR_PATCHWELCOME;
292  }
293 
294  // init libswresample context
295  pan->swr = swr_alloc_set_opts(pan->swr,
296  pan->out_channel_layout, link->format, link->sample_rate,
297  link->channel_layout, link->format, link->sample_rate,
298  0, ctx);
299  if (!pan->swr)
300  return AVERROR(ENOMEM);
301  if (!link->channel_layout) {
302  if (av_opt_set_int(pan->swr, "ich", link->channels, 0) < 0)
303  return AVERROR(EINVAL);
304  }
305  if (!pan->out_channel_layout) {
306  if (av_opt_set_int(pan->swr, "och", pan->nb_output_channels, 0) < 0)
307  return AVERROR(EINVAL);
308  }
309 
310  // gains are pure, init the channel mapping
311  if (pan->pure_gains) {
312 
313  // get channel map from the pure gains
314  for (i = 0; i < pan->nb_output_channels; i++) {
315  int ch_id = -1;
316  for (j = 0; j < link->channels; j++) {
317  if (pan->gain[i][j]) {
318  ch_id = j;
319  break;
320  }
321  }
322  pan->channel_map[i] = ch_id;
323  }
324 
325  av_opt_set_int(pan->swr, "icl", pan->out_channel_layout, 0);
326  av_opt_set_int(pan->swr, "uch", pan->nb_output_channels, 0);
328  } else {
329  // renormalize
330  for (i = 0; i < pan->nb_output_channels; i++) {
331  if (!((pan->need_renorm >> i) & 1))
332  continue;
333  t = 0;
334  for (j = 0; j < link->channels; j++)
335  t += fabs(pan->gain[i][j]);
336  if (t > -1E-5 && t < 1E-5) {
337  // t is almost 0 but not exactly, this is probably a mistake
338  if (t)
339  av_log(ctx, AV_LOG_WARNING,
340  "Degenerate coefficients while renormalizing\n");
341  continue;
342  }
343  for (j = 0; j < link->channels; j++)
344  pan->gain[i][j] /= t;
345  }
346  av_opt_set_int(pan->swr, "icl", link->channel_layout, 0);
347  av_opt_set_int(pan->swr, "ocl", pan->out_channel_layout, 0);
348  swr_set_matrix(pan->swr, pan->gain[0], pan->gain[1] - pan->gain[0]);
349  }
350 
351  r = swr_init(pan->swr);
352  if (r < 0)
353  return r;
354 
355  // summary
356  for (i = 0; i < pan->nb_output_channels; i++) {
357  cur = buf;
358  for (j = 0; j < link->channels; j++) {
359  r = snprintf(cur, buf + sizeof(buf) - cur, "%s%.3g i%d",
360  j ? " + " : "", pan->gain[i][j], j);
361  cur += FFMIN(buf + sizeof(buf) - cur, r);
362  }
363  av_log(ctx, AV_LOG_VERBOSE, "o%d = %s\n", i, buf);
364  }
365  // add channel mapping summary if possible
366  if (pan->pure_gains) {
367  av_log(ctx, AV_LOG_INFO, "Pure channel mapping detected:");
368  for (i = 0; i < pan->nb_output_channels; i++)
369  if (pan->channel_map[i] < 0)
370  av_log(ctx, AV_LOG_INFO, " M");
371  else
372  av_log(ctx, AV_LOG_INFO, " %d", pan->channel_map[i]);
373  av_log(ctx, AV_LOG_INFO, "\n");
374  return 0;
375  }
376  return 0;
377 }
378 
379 static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
380 {
381  int ret;
382  int n = insamples->nb_samples;
383  AVFilterLink *const outlink = inlink->dst->outputs[0];
384  AVFrame *outsamples = ff_get_audio_buffer(outlink, n);
385  PanContext *pan = inlink->dst->priv;
386 
387  if (!outsamples) {
388  av_frame_free(&insamples);
389  return AVERROR(ENOMEM);
390  }
391  swr_convert(pan->swr, outsamples->extended_data, n,
392  (void *)insamples->extended_data, n);
393  av_frame_copy_props(outsamples, insamples);
394  outsamples->channel_layout = outlink->channel_layout;
395  outsamples->channels = outlink->channels;
396 
397  ret = ff_filter_frame(outlink, outsamples);
398  av_frame_free(&insamples);
399  return ret;
400 }
401 
403 {
404  PanContext *pan = ctx->priv;
405  swr_free(&pan->swr);
406 }
407 
408 #define OFFSET(x) offsetof(PanContext, x)
409 
410 static const AVOption pan_options[] = {
411  { "args", NULL, OFFSET(args), AV_OPT_TYPE_STRING, { .str = NULL }, CHAR_MIN, CHAR_MAX, AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM },
412  { NULL }
413 };
414 
416 
417 static const AVFilterPad pan_inputs[] = {
418  {
419  .name = "default",
420  .type = AVMEDIA_TYPE_AUDIO,
421  .config_props = config_props,
422  .filter_frame = filter_frame,
423  },
424  { NULL }
425 };
426 
427 static const AVFilterPad pan_outputs[] = {
428  {
429  .name = "default",
430  .type = AVMEDIA_TYPE_AUDIO,
431  },
432  { NULL }
433 };
434 
436  .name = "pan",
437  .description = NULL_IF_CONFIG_SMALL("Remix channels with coefficients (panning)."),
438  .priv_size = sizeof(PanContext),
439  .priv_class = &pan_class,
440  .init = init,
441  .uninit = uninit,
443  .inputs = pan_inputs,
444  .outputs = pan_outputs,
445 };
#define NULL
Definition: coverity.c:32
char * args
Definition: af_pan.c:44
#define MAX_CHANNELS
Definition: af_pan.c:40
double gain[MAX_CHANNELS][MAX_CHANNELS]
Definition: af_pan.c:46
This structure describes decoded (raw) audio or video data.
Definition: frame.h:201
AVOption.
Definition: opt.h:246
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
Main libavfilter public API header.
#define AV_OPT_FLAG_AUDIO_PARAM
Definition: opt.h:278
static int config_props(AVFilterLink *link)
Definition: af_pan.c:265
int av_get_channel_layout_nb_channels(uint64_t channel_layout)
Return the number of channels in the channel layout.
static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
Definition: af_pan.c:379
const char * name
Pad name.
Definition: internal.h:60
uint64_t av_get_channel_layout(const char *name)
Return a channel layout id that matches name, or 0 if no match is found.
AVFilterLink ** inputs
array of pointers to input links
Definition: avfilter.h:346
int ff_channel_layouts_ref(AVFilterChannelLayouts *f, AVFilterChannelLayouts **ref)
Add *ref as a new reference to f.
Definition: formats.c:435
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1113
#define av_cold
Definition: attributes.h:82
AVOptions.
int need_renumber
Definition: af_pan.c:48
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:192
#define av_log(a,...)
AVFilterFormats * ff_all_formats(enum AVMediaType type)
Return a list of all formats supported by FFmpeg for the given media type.
Definition: formats.c:350
static const AVFilterPad pan_inputs[]
Definition: af_pan.c:417
static const AVOption pan_options[]
Definition: af_pan.c:410
A filter pad used for either input or output.
Definition: internal.h:54
libswresample public header
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
int ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)
A helper for query_formats() which sets all links to the same list of formats.
Definition: formats.c:568
int ff_add_channel_layout(AVFilterChannelLayouts **l, uint64_t channel_layout)
Definition: formats.c:343
AVFrame * ff_get_audio_buffer(AVFilterLink *link, int nb_samples)
Request an audio samples buffer with a specific set of permissions.
Definition: audio.c:86
#define AV_OPT_FLAG_FILTERING_PARAM
a generic parameter which can be set by the user for filtering
Definition: opt.h:290
#define AVERROR(e)
Definition: error.h:43
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:163
The libswresample context.
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
const char * r
Definition: vf_curves.c:111
void * priv
private data for use by the filter
Definition: avfilter.h:353
int ff_parse_channel_layout(int64_t *ret, int *nret, const char *arg, void *log_ctx)
Parse a channel layout or a corresponding integer representation.
Definition: formats.c:662
static int query_formats(AVFilterContext *ctx)
Definition: af_pan.c:233
const char * arg
Definition: jacosubdec.c:66
int av_opt_set_int(void *obj, const char *name, int64_t val, int search_flags)
Definition: opt.c:558
struct SwrContext * swr
Definition: af_pan.c:54
#define fail()
Definition: checkasm.h:113
static int are_gains_pure(const PanContext *pan)
Definition: af_pan.c:211
uint64_t channel_layout
Channel layout of the audio data.
Definition: frame.h:379
int channels
number of audio channels, only used for audio.
Definition: frame.h:506
audio channel layout utility functions
#define E
Definition: avdct.c:32
#define FFMIN(a, b)
Definition: common.h:96
int swr_set_matrix(struct SwrContext *s, const double *matrix, int stride)
Set a customized remix matrix.
Definition: rematrix.c:64
int pure_gains
Definition: af_pan.c:51
static void skip_spaces(char **arg)
Definition: af_pan.c:57
AVFormatContext * ctx
Definition: movenc.c:48
struct SwrContext * swr_alloc_set_opts(struct SwrContext *s, int64_t out_ch_layout, enum AVSampleFormat out_sample_fmt, int out_sample_rate, int64_t in_ch_layout, enum AVSampleFormat in_sample_fmt, int in_sample_rate, int log_offset, void *log_ctx)
Allocate SwrContext if needed and set/reset common parameters.
Definition: swresample.c:59
AVFilter ff_af_pan
Definition: af_pan.c:435
int n
Definition: avisynth_c.h:684
static const AVFilterPad inputs[]
Definition: af_acontrast.c:193
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
A list of supported channel layouts.
Definition: formats.h:85
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
int64_t out_channel_layout
Definition: af_pan.c:45
#define AV_LOG_INFO
Standard information.
Definition: log.h:187
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:251
av_cold void swr_free(SwrContext **ss)
Free the given SwrContext and set the pointer to NULL.
Definition: swresample.c:137
void * buf
Definition: avisynth_c.h:690
int swr_set_channel_mapping(struct SwrContext *s, const int *channel_map)
Set a customized input channel mapping.
Definition: swresample.c:52
Describe the class of an AVClass context structure.
Definition: log.h:67
Filter definition.
Definition: avfilter.h:144
#define OFFSET(x)
Definition: af_pan.c:408
int64_t need_renorm
Definition: af_pan.c:47
int channel_map[MAX_CHANNELS]
Definition: af_pan.c:53
const char * name
Filter name.
Definition: avfilter.h:148
#define snprintf
Definition: snprintf.h:34
int attribute_align_arg swr_convert(struct SwrContext *s, uint8_t *out_arg[SWR_CH_MAX], int out_count, const uint8_t *in_arg[SWR_CH_MAX], int in_count)
Definition: swresample.c:706
AVFilterLink ** outputs
array of pointers to output links
Definition: avfilter.h:350
enum MovChannelLayoutTag * layouts
Definition: mov_chan.c:434
AVFilterFormats * ff_all_samplerates(void)
Definition: formats.c:395
AVFILTER_DEFINE_CLASS(pan)
char * av_strtok(char *s, const char *delim, char **saveptr)
Split the string into several tokens which can be accessed by successive calls to av_strtok()...
Definition: avstring.c:184
static int parse_channel_name(char **arg, int *rchannel, int *rnamed)
Definition: af_pan.c:65
#define av_free(p)
int len
static av_cold int init(AVFilterContext *ctx)
Definition: af_pan.c:101
A list of supported formats for one end of a filter link.
Definition: formats.h:64
uint64_t layout
An instance of a filter.
Definition: avfilter.h:338
#define FF_COUNT2LAYOUT(c)
Encode a channel count as a channel layout.
Definition: formats.h:102
formats
Definition: signature.h:48
internal API functions
AVFilterChannelLayouts * ff_all_channel_counts(void)
Construct an AVFilterChannelLayouts coding for any channel layout, with known or unknown disposition...
Definition: formats.c:410
uint8_t ** extended_data
pointers to the data planes/channels.
Definition: frame.h:248
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:267
static av_cold void uninit(AVFilterContext *ctx)
Definition: af_pan.c:402
int ff_set_common_samplerates(AVFilterContext *ctx, AVFilterFormats *samplerates)
Definition: formats.c:556
int av_frame_copy_props(AVFrame *dst, const AVFrame *src)
Copy only "metadata" fields from src to dst.
Definition: frame.c:609
av_cold int swr_init(struct SwrContext *s)
Initialize context after user parameters have been set.
Definition: swresample.c:152
static const AVFilterPad pan_outputs[]
Definition: af_pan.c:427
int nb_output_channels
Definition: af_pan.c:49