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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  int used_out_ch[MAX_CHANNELS] = {0};
108  double gain;
109 
110  if (!pan->args) {
111  av_log(ctx, AV_LOG_ERROR,
112  "pan filter needs a channel layout and a set "
113  "of channel definitions as parameter\n");
114  return AVERROR(EINVAL);
115  }
116  if (!args)
117  return AVERROR(ENOMEM);
118  arg = av_strtok(args, "|", &tokenizer);
119  if (!arg) {
120  av_log(ctx, AV_LOG_ERROR, "Channel layout not specified\n");
121  ret = AVERROR(EINVAL);
122  goto fail;
123  }
125  &pan->nb_output_channels, arg, ctx);
126  if (ret < 0)
127  goto fail;
128 
129  /* parse channel specifications */
130  while ((arg = arg0 = av_strtok(NULL, "|", &tokenizer))) {
131  int used_in_ch[MAX_CHANNELS] = {0};
132  /* channel name */
133  if (parse_channel_name(&arg, &out_ch_id, &named)) {
134  av_log(ctx, AV_LOG_ERROR,
135  "Expected out channel name, got \"%.8s\"\n", arg);
136  ret = AVERROR(EINVAL);
137  goto fail;
138  }
139  if (named) {
140  if (!((pan->out_channel_layout >> out_ch_id) & 1)) {
141  av_log(ctx, AV_LOG_ERROR,
142  "Channel \"%.8s\" does not exist in the chosen layout\n", arg0);
143  ret = AVERROR(EINVAL);
144  goto fail;
145  }
146  /* get the channel number in the output channel layout:
147  * out_channel_layout & ((1 << out_ch_id) - 1) are all the
148  * channels that come before out_ch_id,
149  * so their count is the index of out_ch_id */
150  out_ch_id = av_get_channel_layout_nb_channels(pan->out_channel_layout & (((int64_t)1 << out_ch_id) - 1));
151  }
152  if (out_ch_id < 0 || out_ch_id >= pan->nb_output_channels) {
153  av_log(ctx, AV_LOG_ERROR,
154  "Invalid out channel name \"%.8s\"\n", arg0);
155  ret = AVERROR(EINVAL);
156  goto fail;
157  }
158  if (used_out_ch[out_ch_id]) {
159  av_log(ctx, AV_LOG_ERROR,
160  "Can not reference out channel %d twice\n", out_ch_id);
161  ret = AVERROR(EINVAL);
162  goto fail;
163  }
164  used_out_ch[out_ch_id] = 1;
165  skip_spaces(&arg);
166  if (*arg == '=') {
167  arg++;
168  } else if (*arg == '<') {
169  pan->need_renorm |= (int64_t)1 << out_ch_id;
170  arg++;
171  } else {
172  av_log(ctx, AV_LOG_ERROR,
173  "Syntax error after channel name in \"%.8s\"\n", arg0);
174  ret = AVERROR(EINVAL);
175  goto fail;
176  }
177  /* gains */
178  sign = 1;
179  while (1) {
180  gain = 1;
181  if (sscanf(arg, "%lf%n *%n", &gain, &len, &len))
182  arg += len;
183  if (parse_channel_name(&arg, &in_ch_id, &named)){
184  av_log(ctx, AV_LOG_ERROR,
185  "Expected in channel name, got \"%.8s\"\n", arg);
186  ret = AVERROR(EINVAL);
187  goto fail;
188  }
189  nb_in_channels[named]++;
190  if (nb_in_channels[!named]) {
191  av_log(ctx, AV_LOG_ERROR,
192  "Can not mix named and numbered channels\n");
193  ret = AVERROR(EINVAL);
194  goto fail;
195  }
196  if (used_in_ch[in_ch_id]) {
197  av_log(ctx, AV_LOG_ERROR,
198  "Can not reference in channel %d twice\n", in_ch_id);
199  ret = AVERROR(EINVAL);
200  goto fail;
201  }
202  used_in_ch[in_ch_id] = 1;
203  pan->gain[out_ch_id][in_ch_id] = sign * gain;
204  skip_spaces(&arg);
205  if (!*arg)
206  break;
207  if (*arg == '-') {
208  sign = -1;
209  } else if (*arg != '+') {
210  av_log(ctx, AV_LOG_ERROR, "Syntax error near \"%.8s\"\n", arg);
211  ret = AVERROR(EINVAL);
212  goto fail;
213  } else {
214  sign = 1;
215  }
216  arg++;
217  }
218  }
219  pan->need_renumber = !!nb_in_channels[1];
220 
221  ret = 0;
222 fail:
223  av_free(args);
224  return ret;
225 }
226 
227 static int are_gains_pure(const PanContext *pan)
228 {
229  int i, j;
230 
231  for (i = 0; i < MAX_CHANNELS; i++) {
232  int nb_gain = 0;
233 
234  for (j = 0; j < MAX_CHANNELS; j++) {
235  double gain = pan->gain[i][j];
236 
237  /* channel mapping is effective only if 0% or 100% of a channel is
238  * selected... */
239  if (gain != 0. && gain != 1.)
240  return 0;
241  /* ...and if the output channel is only composed of one input */
242  if (gain && nb_gain++)
243  return 0;
244  }
245  }
246  return 1;
247 }
248 
250 {
251  PanContext *pan = ctx->priv;
252  AVFilterLink *inlink = ctx->inputs[0];
253  AVFilterLink *outlink = ctx->outputs[0];
256  int ret;
257 
258  pan->pure_gains = are_gains_pure(pan);
259  /* libswr supports any sample and packing formats */
261  return ret;
262 
263  formats = ff_all_samplerates();
264  if ((ret = ff_set_common_samplerates(ctx, formats)) < 0)
265  return ret;
266 
267  // inlink supports any channel layout
268  layouts = ff_all_channel_counts();
269  if ((ret = ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts)) < 0)
270  return ret;
271 
272  // outlink supports only requested output channel layout
273  layouts = NULL;
274  if ((ret = ff_add_channel_layout(&layouts,
277  return ret;
278  return ff_channel_layouts_ref(layouts, &outlink->in_channel_layouts);
279 }
280 
281 static int config_props(AVFilterLink *link)
282 {
283  AVFilterContext *ctx = link->dst;
284  PanContext *pan = ctx->priv;
285  char buf[1024], *cur;
286  int i, j, k, r;
287  double t;
288 
289  if (pan->need_renumber) {
290  // input channels were given by their name: renumber them
291  for (i = j = 0; i < MAX_CHANNELS; i++) {
292  if ((link->channel_layout >> i) & 1) {
293  for (k = 0; k < pan->nb_output_channels; k++)
294  pan->gain[k][j] = pan->gain[k][i];
295  j++;
296  }
297  }
298  }
299 
300  // sanity check; can't be done in query_formats since the inlink
301  // channel layout is unknown at that time
302  if (link->channels > MAX_CHANNELS ||
304  av_log(ctx, AV_LOG_ERROR,
305  "af_pan supports a maximum of %d channels. "
306  "Feel free to ask for a higher limit.\n", MAX_CHANNELS);
307  return AVERROR_PATCHWELCOME;
308  }
309 
310  // init libswresample context
311  pan->swr = swr_alloc_set_opts(pan->swr,
312  pan->out_channel_layout, link->format, link->sample_rate,
313  link->channel_layout, link->format, link->sample_rate,
314  0, ctx);
315  if (!pan->swr)
316  return AVERROR(ENOMEM);
317  if (!link->channel_layout) {
318  if (av_opt_set_int(pan->swr, "ich", link->channels, 0) < 0)
319  return AVERROR(EINVAL);
320  }
321  if (!pan->out_channel_layout) {
322  if (av_opt_set_int(pan->swr, "och", pan->nb_output_channels, 0) < 0)
323  return AVERROR(EINVAL);
324  }
325 
326  // gains are pure, init the channel mapping
327  if (pan->pure_gains) {
328 
329  // get channel map from the pure gains
330  for (i = 0; i < pan->nb_output_channels; i++) {
331  int ch_id = -1;
332  for (j = 0; j < link->channels; j++) {
333  if (pan->gain[i][j]) {
334  ch_id = j;
335  break;
336  }
337  }
338  pan->channel_map[i] = ch_id;
339  }
340 
341  av_opt_set_int(pan->swr, "icl", pan->out_channel_layout, 0);
342  av_opt_set_int(pan->swr, "uch", pan->nb_output_channels, 0);
344  } else {
345  // renormalize
346  for (i = 0; i < pan->nb_output_channels; i++) {
347  if (!((pan->need_renorm >> i) & 1))
348  continue;
349  t = 0;
350  for (j = 0; j < link->channels; j++)
351  t += fabs(pan->gain[i][j]);
352  if (t > -1E-5 && t < 1E-5) {
353  // t is almost 0 but not exactly, this is probably a mistake
354  if (t)
355  av_log(ctx, AV_LOG_WARNING,
356  "Degenerate coefficients while renormalizing\n");
357  continue;
358  }
359  for (j = 0; j < link->channels; j++)
360  pan->gain[i][j] /= t;
361  }
362  av_opt_set_int(pan->swr, "icl", link->channel_layout, 0);
363  av_opt_set_int(pan->swr, "ocl", pan->out_channel_layout, 0);
364  swr_set_matrix(pan->swr, pan->gain[0], pan->gain[1] - pan->gain[0]);
365  }
366 
367  r = swr_init(pan->swr);
368  if (r < 0)
369  return r;
370 
371  // summary
372  for (i = 0; i < pan->nb_output_channels; i++) {
373  cur = buf;
374  for (j = 0; j < link->channels; j++) {
375  r = snprintf(cur, buf + sizeof(buf) - cur, "%s%.3g i%d",
376  j ? " + " : "", pan->gain[i][j], j);
377  cur += FFMIN(buf + sizeof(buf) - cur, r);
378  }
379  av_log(ctx, AV_LOG_VERBOSE, "o%d = %s\n", i, buf);
380  }
381  // add channel mapping summary if possible
382  if (pan->pure_gains) {
383  av_log(ctx, AV_LOG_INFO, "Pure channel mapping detected:");
384  for (i = 0; i < pan->nb_output_channels; i++)
385  if (pan->channel_map[i] < 0)
386  av_log(ctx, AV_LOG_INFO, " M");
387  else
388  av_log(ctx, AV_LOG_INFO, " %d", pan->channel_map[i]);
389  av_log(ctx, AV_LOG_INFO, "\n");
390  return 0;
391  }
392  return 0;
393 }
394 
395 static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
396 {
397  int ret;
398  int n = insamples->nb_samples;
399  AVFilterLink *const outlink = inlink->dst->outputs[0];
400  AVFrame *outsamples = ff_get_audio_buffer(outlink, n);
401  PanContext *pan = inlink->dst->priv;
402 
403  if (!outsamples) {
404  av_frame_free(&insamples);
405  return AVERROR(ENOMEM);
406  }
407  swr_convert(pan->swr, outsamples->extended_data, n,
408  (void *)insamples->extended_data, n);
409  av_frame_copy_props(outsamples, insamples);
410  outsamples->channel_layout = outlink->channel_layout;
411  outsamples->channels = outlink->channels;
412 
413  ret = ff_filter_frame(outlink, outsamples);
414  av_frame_free(&insamples);
415  return ret;
416 }
417 
419 {
420  PanContext *pan = ctx->priv;
421  swr_free(&pan->swr);
422 }
423 
424 #define OFFSET(x) offsetof(PanContext, x)
425 
426 static const AVOption pan_options[] = {
427  { "args", NULL, OFFSET(args), AV_OPT_TYPE_STRING, { .str = NULL }, CHAR_MIN, CHAR_MAX, AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM },
428  { NULL }
429 };
430 
432 
433 static const AVFilterPad pan_inputs[] = {
434  {
435  .name = "default",
436  .type = AVMEDIA_TYPE_AUDIO,
437  .config_props = config_props,
438  .filter_frame = filter_frame,
439  },
440  { NULL }
441 };
442 
443 static const AVFilterPad pan_outputs[] = {
444  {
445  .name = "default",
446  .type = AVMEDIA_TYPE_AUDIO,
447  },
448  { NULL }
449 };
450 
452  .name = "pan",
453  .description = NULL_IF_CONFIG_SMALL("Remix channels with coefficients (panning)."),
454  .priv_size = sizeof(PanContext),
455  .priv_class = &pan_class,
456  .init = init,
457  .uninit = uninit,
459  .inputs = pan_inputs,
460  .outputs = pan_outputs,
461 };
#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:218
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:281
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:395
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:1080
#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:433
static const AVOption pan_options[]
Definition: af_pan.c:426
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:291
#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:202
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:249
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:561
struct SwrContext * swr
Definition: af_pan.c:54
#define fail()
Definition: checkasm.h:117
static int are_gains_pure(const PanContext *pan)
Definition: af_pan.c:227
uint64_t channel_layout
Channel layout of the audio data.
Definition: frame.h:396
int channels
number of audio channels, only used for audio.
Definition: frame.h:523
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:451
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:424
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:265
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:284
static av_cold void uninit(AVFilterContext *ctx)
Definition: af_pan.c:418
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:652
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:443
int nb_output_channels
Definition: af_pan.c:49