FFmpeg
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, channel_id = 0;
69 
71  /* try to parse a channel name, e.g. "FL" */
72  if (sscanf(*arg, "%7[A-Z]%n", buf, &len)) {
73  channel_id = av_channel_from_string(buf);
74  if (channel_id < 0)
75  return channel_id;
76 
77  *rchannel = channel_id;
78  *rnamed = 1;
79  *arg += len;
80  return 0;
81  }
82  /* try to parse a channel number, e.g. "c2" */
83  if (sscanf(*arg, "c%d%n", &channel_id, &len) &&
84  channel_id >= 0 && channel_id < MAX_CHANNELS) {
85  *rchannel = channel_id;
86  *rnamed = 0;
87  *arg += len;
88  return 0;
89  }
90  return AVERROR(EINVAL);
91 }
92 
94 {
95  PanContext *const pan = ctx->priv;
96  char *arg, *arg0, *tokenizer, *args = av_strdup(pan->args);
97  int out_ch_id, in_ch_id, len, named, ret, sign = 1;
98  int nb_in_channels[2] = { 0, 0 }; // number of unnamed and named input channels
99  int used_out_ch[MAX_CHANNELS] = {0};
100  double gain;
101 
102  if (!pan->args) {
104  "pan filter needs a channel layout and a set "
105  "of channel definitions as parameter\n");
106  return AVERROR(EINVAL);
107  }
108  if (!args)
109  return AVERROR(ENOMEM);
110  arg = av_strtok(args, "|", &tokenizer);
111  if (!arg) {
112  av_log(ctx, AV_LOG_ERROR, "Channel layout not specified\n");
113  ret = AVERROR(EINVAL);
114  goto fail;
115  }
117  &pan->nb_output_channels, arg, ctx);
118  if (ret < 0)
119  goto fail;
120 
121  /* parse channel specifications */
122  while ((arg = arg0 = av_strtok(NULL, "|", &tokenizer))) {
123  int used_in_ch[MAX_CHANNELS] = {0};
124  /* channel name */
125  if (parse_channel_name(&arg, &out_ch_id, &named)) {
127  "Expected out channel name, got \"%.8s\"\n", arg);
128  ret = AVERROR(EINVAL);
129  goto fail;
130  }
131  if (named) {
132  if ((out_ch_id = av_channel_layout_index_from_channel(&pan->out_channel_layout, out_ch_id)) < 0) {
134  "Channel \"%.8s\" does not exist in the chosen layout\n", arg0);
135  ret = AVERROR(EINVAL);
136  goto fail;
137  }
138  }
139  if (out_ch_id < 0 || out_ch_id >= pan->nb_output_channels) {
141  "Invalid out channel name \"%.8s\"\n", arg0);
142  ret = AVERROR(EINVAL);
143  goto fail;
144  }
145  if (used_out_ch[out_ch_id]) {
147  "Can not reference out channel %d twice\n", out_ch_id);
148  ret = AVERROR(EINVAL);
149  goto fail;
150  }
151  used_out_ch[out_ch_id] = 1;
152  skip_spaces(&arg);
153  if (*arg == '=') {
154  arg++;
155  } else if (*arg == '<') {
156  pan->need_renorm |= (int64_t)1 << out_ch_id;
157  arg++;
158  } else {
160  "Syntax error after channel name in \"%.8s\"\n", arg0);
161  ret = AVERROR(EINVAL);
162  goto fail;
163  }
164  /* gains */
165  sign = 1;
166  while (1) {
167  gain = 1;
168  if (sscanf(arg, "%lf%n *%n", &gain, &len, &len))
169  arg += len;
170  if (parse_channel_name(&arg, &in_ch_id, &named)){
172  "Expected in channel name, got \"%.8s\"\n", arg);
173  ret = AVERROR(EINVAL);
174  goto fail;
175  }
176  nb_in_channels[named]++;
177  if (nb_in_channels[!named]) {
179  "Can not mix named and numbered channels\n");
180  ret = AVERROR(EINVAL);
181  goto fail;
182  }
183  if (used_in_ch[in_ch_id]) {
185  "Can not reference in channel %d twice\n", in_ch_id);
186  ret = AVERROR(EINVAL);
187  goto fail;
188  }
189  used_in_ch[in_ch_id] = 1;
190  pan->gain[out_ch_id][in_ch_id] = sign * gain;
191  skip_spaces(&arg);
192  if (!*arg)
193  break;
194  if (*arg == '-') {
195  sign = -1;
196  } else if (*arg != '+') {
197  av_log(ctx, AV_LOG_ERROR, "Syntax error near \"%.8s\"\n", arg);
198  ret = AVERROR(EINVAL);
199  goto fail;
200  } else {
201  sign = 1;
202  }
203  arg++;
204  }
205  }
206  pan->need_renumber = !!nb_in_channels[1];
207 
208  ret = 0;
209 fail:
210  av_free(args);
211  return ret;
212 }
213 
214 static int are_gains_pure(const PanContext *pan)
215 {
216  int i, j;
217 
218  for (i = 0; i < MAX_CHANNELS; i++) {
219  int nb_gain = 0;
220 
221  for (j = 0; j < MAX_CHANNELS; j++) {
222  double gain = pan->gain[i][j];
223 
224  /* channel mapping is effective only if 0% or 100% of a channel is
225  * selected... */
226  if (gain != 0. && gain != 1.)
227  return 0;
228  /* ...and if the output channel is only composed of one input */
229  if (gain && nb_gain++)
230  return 0;
231  }
232  }
233  return 1;
234 }
235 
237 {
238  PanContext *pan = ctx->priv;
239  AVFilterLink *inlink = ctx->inputs[0];
240  AVFilterLink *outlink = ctx->outputs[0];
242  int ret;
243 
244  pan->pure_gains = are_gains_pure(pan);
245  /* libswr supports any sample and packing formats */
247  return ret;
248 
250  return ret;
251 
252  // inlink supports any channel layout
254  if ((ret = ff_channel_layouts_ref(layouts, &inlink->outcfg.channel_layouts)) < 0)
255  return ret;
256 
257  // outlink supports only requested output channel layout
258  layouts = NULL;
260  return ret;
262 }
263 
265 {
266  AVFilterContext *ctx = link->dst;
267  PanContext *pan = ctx->priv;
268  char buf[1024], *cur;
269  int i, j, k, r, ret;
270  double t;
271 
272  if (pan->need_renumber) {
273  // input channels were given by their name: renumber them
274  for (i = j = 0; i < MAX_CHANNELS; i++) {
276  for (k = 0; k < pan->nb_output_channels; k++)
277  pan->gain[k][j] = pan->gain[k][i];
278  j++;
279  }
280  }
281  }
282 
283  // sanity check; can't be done in query_formats since the inlink
284  // channel layout is unknown at that time
288  "af_pan supports a maximum of %d channels. "
289  "Feel free to ask for a higher limit.\n", MAX_CHANNELS);
290  return AVERROR_PATCHWELCOME;
291  }
292 
293  // init libswresample context
294  ret = swr_alloc_set_opts2(&pan->swr,
297  0, ctx);
298  if (ret < 0)
299  return AVERROR(ENOMEM);
300 
301  // gains are pure, init the channel mapping
302  if (pan->pure_gains) {
303 
304  // get channel map from the pure gains
305  for (i = 0; i < pan->nb_output_channels; i++) {
306  int ch_id = -1;
307  for (j = 0; j < link->ch_layout.nb_channels; j++) {
308  if (pan->gain[i][j]) {
309  ch_id = j;
310  break;
311  }
312  }
313  pan->channel_map[i] = ch_id;
314  }
315 
316  av_opt_set_int(pan->swr, "uch", pan->nb_output_channels, 0);
318  } else {
319  // renormalize
320  for (i = 0; i < pan->nb_output_channels; i++) {
321  if (!((pan->need_renorm >> i) & 1))
322  continue;
323  t = 0;
324  for (j = 0; j < link->ch_layout.nb_channels; j++)
325  t += fabs(pan->gain[i][j]);
326  if (t > -1E-5 && t < 1E-5) {
327  // t is almost 0 but not exactly, this is probably a mistake
328  if (t)
330  "Degenerate coefficients while renormalizing\n");
331  continue;
332  }
333  for (j = 0; j < link->ch_layout.nb_channels; j++)
334  pan->gain[i][j] /= t;
335  }
336  swr_set_matrix(pan->swr, pan->gain[0], pan->gain[1] - pan->gain[0]);
337  }
338 
339  r = swr_init(pan->swr);
340  if (r < 0)
341  return r;
342 
343  // summary
344  for (i = 0; i < pan->nb_output_channels; i++) {
345  cur = buf;
346  for (j = 0; j < link->ch_layout.nb_channels; j++) {
347  r = snprintf(cur, buf + sizeof(buf) - cur, "%s%.3g i%d",
348  j ? " + " : "", pan->gain[i][j], j);
349  cur += FFMIN(buf + sizeof(buf) - cur, r);
350  }
351  av_log(ctx, AV_LOG_VERBOSE, "o%d = %s\n", i, buf);
352  }
353  // add channel mapping summary if possible
354  if (pan->pure_gains) {
355  av_log(ctx, AV_LOG_INFO, "Pure channel mapping detected:");
356  for (i = 0; i < pan->nb_output_channels; i++)
357  if (pan->channel_map[i] < 0)
358  av_log(ctx, AV_LOG_INFO, " M");
359  else
360  av_log(ctx, AV_LOG_INFO, " %d", pan->channel_map[i]);
361  av_log(ctx, AV_LOG_INFO, "\n");
362  return 0;
363  }
364  return 0;
365 }
366 
367 static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
368 {
369  int ret;
370  int n = insamples->nb_samples;
371  AVFilterLink *const outlink = inlink->dst->outputs[0];
372  AVFrame *outsamples = ff_get_audio_buffer(outlink, n);
373  PanContext *pan = inlink->dst->priv;
374 
375  if (!outsamples) {
376  av_frame_free(&insamples);
377  return AVERROR(ENOMEM);
378  }
379  swr_convert(pan->swr, outsamples->extended_data, n,
380  (void *)insamples->extended_data, n);
381  av_frame_copy_props(outsamples, insamples);
382 #if FF_API_OLD_CHANNEL_LAYOUT
384  outsamples->channel_layout = outlink->channel_layout;
385  outsamples->channels = outlink->ch_layout.nb_channels;
387 #endif
388  if ((ret = av_channel_layout_copy(&outsamples->ch_layout, &outlink->ch_layout)) < 0)
389  return ret;
390 
391  ret = ff_filter_frame(outlink, outsamples);
392  av_frame_free(&insamples);
393  return ret;
394 }
395 
397 {
398  PanContext *pan = ctx->priv;
399  swr_free(&pan->swr);
400 }
401 
402 #define OFFSET(x) offsetof(PanContext, x)
403 
404 static const AVOption pan_options[] = {
406  { NULL }
407 };
408 
410 
411 static const AVFilterPad pan_inputs[] = {
412  {
413  .name = "default",
414  .type = AVMEDIA_TYPE_AUDIO,
415  .config_props = config_props,
416  .filter_frame = filter_frame,
417  },
418 };
419 
420 static const AVFilterPad pan_outputs[] = {
421  {
422  .name = "default",
423  .type = AVMEDIA_TYPE_AUDIO,
424  },
425 };
426 
428  .name = "pan",
429  .description = NULL_IF_CONFIG_SMALL("Remix channels with coefficients (panning)."),
430  .priv_size = sizeof(PanContext),
431  .priv_class = &pan_class,
432  .init = init,
433  .uninit = uninit,
437 };
ff_get_audio_buffer
AVFrame * ff_get_audio_buffer(AVFilterLink *link, int nb_samples)
Request an audio samples buffer with a specific set of permissions.
Definition: audio.c:100
FF_ENABLE_DEPRECATION_WARNINGS
#define FF_ENABLE_DEPRECATION_WARNINGS
Definition: internal.h:82
AVFilterChannelLayouts
A list of supported channel layouts.
Definition: formats.h:85
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:186
PanContext::out_channel_layout
AVChannelLayout out_channel_layout
Definition: af_pan.c:45
r
const char * r
Definition: vf_curves.c:126
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
opt.h
AVFilterFormatsConfig::channel_layouts
AVFilterChannelLayouts * channel_layouts
Lists of supported channel layouts, only for audio.
Definition: avfilter.h:529
ff_filter_frame
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1009
ff_channel_layouts_ref
int ff_channel_layouts_ref(AVFilterChannelLayouts *f, AVFilterChannelLayouts **ref)
Add *ref as a new reference to f.
Definition: formats.c:591
layouts
enum MovChannelLayoutTag * layouts
Definition: mov_chan.c:326
inlink
The exact code depends on how similar the blocks are and how related they are to the and needs to apply these operations to the correct inlink or outlink if there are several Macros are available to factor that when no extra processing is inlink
Definition: filter_design.txt:212
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:116
ff_all_channel_counts
AVFilterChannelLayouts * ff_all_channel_counts(void)
Construct an AVFilterChannelLayouts coding for any channel layout, with known or unknown disposition.
Definition: formats.c:566
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:325
AVOption
AVOption.
Definition: opt.h:251
config_props
static int config_props(AVFilterLink *link)
Definition: af_pan.c:264
FILTER_QUERY_FUNC
#define FILTER_QUERY_FUNC(func)
Definition: internal.h:167
pan_outputs
static const AVFilterPad pan_outputs[]
Definition: af_pan.c:420
AV_LOG_VERBOSE
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:196
ff_set_common_all_samplerates
int ff_set_common_all_samplerates(AVFilterContext *ctx)
Equivalent to ff_set_common_samplerates(ctx, ff_all_samplerates())
Definition: formats.c:739
swr_set_channel_mapping
int swr_set_channel_mapping(struct SwrContext *s, const int *channel_map)
Set a customized input channel mapping.
Definition: swresample.c:32
AVFilter::name
const char * name
Filter name.
Definition: avfilter.h:175
AVChannelLayout::nb_channels
int nb_channels
Number of channels in this layout.
Definition: channel_layout.h:311
AV_OPT_FLAG_FILTERING_PARAM
#define AV_OPT_FLAG_FILTERING_PARAM
a generic parameter which can be set by the user for filtering
Definition: opt.h:297
swr_set_matrix
int swr_set_matrix(struct SwrContext *s, const double *matrix, int stride)
Set a customized remix matrix.
Definition: rematrix.c:64
ff_af_pan
const AVFilter ff_af_pan
Definition: af_pan.c:427
formats.h
fail
#define fail()
Definition: checkasm.h:134
AVFrame::ch_layout
AVChannelLayout ch_layout
Channel layout of the audio data.
Definition: frame.h:709
AVFrame::channels
attribute_deprecated int channels
number of audio channels, only used for audio.
Definition: frame.h:648
ff_all_formats
AVFilterFormats * ff_all_formats(enum AVMediaType type)
Return a list of all formats supported by FFmpeg for the given media type.
Definition: formats.c:480
AVFilterPad
A filter pad used for either input or output.
Definition: internal.h:49
PanContext::pure_gains
int pure_gains
Definition: af_pan.c:51
PanContext::swr
struct SwrContext * swr
Definition: af_pan.c:54
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
av_cold
#define av_cold
Definition: attributes.h:90
AVFrame::channel_layout
attribute_deprecated uint64_t channel_layout
Channel layout of the audio data.
Definition: frame.h:510
ff_set_common_formats
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:749
swr_init
av_cold int swr_init(struct SwrContext *s)
Initialize context after user parameters have been set.
Definition: swresample.c:191
PanContext::args
char * args
Definition: af_pan.c:44
filter_frame
static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
Definition: af_pan.c:367
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
query_formats
static int query_formats(AVFilterContext *ctx)
Definition: af_pan.c:236
av_strtok
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:189
skip_spaces
static void skip_spaces(char **arg)
Definition: af_pan.c:57
ctx
AVFormatContext * ctx
Definition: movenc.c:48
SwrContext
The libswresample context.
Definition: swresample_internal.h:95
FILTER_INPUTS
#define FILTER_INPUTS(array)
Definition: internal.h:190
E
#define E
Definition: avdct.c:32
link
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a link
Definition: filter_design.txt:23
AV_OPT_FLAG_AUDIO_PARAM
#define AV_OPT_FLAG_AUDIO_PARAM
Definition: opt.h:283
arg
const char * arg
Definition: jacosubdec.c:67
PanContext::need_renorm
int64_t need_renorm
Definition: af_pan.c:47
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
fabs
static __device__ float fabs(float a)
Definition: cuda_runtime.h:182
NULL
#define NULL
Definition: coverity.c:32
AVERROR_PATCHWELCOME
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:64
av_frame_copy_props
int av_frame_copy_props(AVFrame *dst, const AVFrame *src)
Copy only "metadata" fields from src to dst.
Definition: frame.c:603
pan_inputs
static const AVFilterPad pan_inputs[]
Definition: af_pan.c:411
are_gains_pure
static int are_gains_pure(const PanContext *pan)
Definition: af_pan.c:214
pan_options
static const AVOption pan_options[]
Definition: af_pan.c:404
ff_add_channel_layout
int ff_add_channel_layout(AVFilterChannelLayouts **l, const AVChannelLayout *channel_layout)
Definition: formats.c:466
PanContext::nb_output_channels
int nb_output_channels
Definition: af_pan.c:49
swresample.h
av_opt_set_int
int av_opt_set_int(void *obj, const char *name, int64_t val, int search_flags)
Definition: opt.c:624
OFFSET
#define OFFSET(x)
Definition: af_pan.c:402
swr_alloc_set_opts2
int swr_alloc_set_opts2(struct SwrContext **ps, const AVChannelLayout *out_ch_layout, enum AVSampleFormat out_sample_fmt, int out_sample_rate, const AVChannelLayout *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:85
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:115
AVChannelLayout
An AVChannelLayout holds information about the channel layout of audio data.
Definition: channel_layout.h:301
ff_parse_channel_layout
int ff_parse_channel_layout(AVChannelLayout *ret, int *nret, const char *arg, void *log_ctx)
Parse a channel layout or a corresponding integer representation.
Definition: formats.c:839
AVFrame::sample_rate
int sample_rate
Sample rate of the audio data.
Definition: frame.h:502
PanContext::need_renumber
int need_renumber
Definition: af_pan.c:48
swr_free
av_cold void swr_free(SwrContext **ss)
Free the given SwrContext and set the pointer to NULL.
Definition: swresample.c:173
swr_convert
int attribute_align_arg swr_convert(struct SwrContext *s, uint8_t **out_arg, int out_count, const uint8_t **in_arg, int in_count)
Convert audio.
Definition: swresample.c:816
AVFrame::format
int format
format of the frame, -1 if unknown or unset Values correspond to enum AVPixelFormat for video frames,...
Definition: frame.h:412
PanContext::channel_map
int channel_map[MAX_CHANNELS]
Definition: af_pan.c:53
AV_LOG_INFO
#define AV_LOG_INFO
Standard information.
Definition: log.h:191
internal.h
AVFrame::nb_samples
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:405
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
AVFrame::extended_data
uint8_t ** extended_data
pointers to the data planes/channels.
Definition: frame.h:386
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
len
int len
Definition: vorbis_enc_data.h:426
AVFilterPad::name
const char * name
Pad name.
Definition: internal.h:55
AVFilter
Filter definition.
Definition: avfilter.h:171
ret
ret
Definition: filter_design.txt:187
av_channel_from_string
enum AVChannel av_channel_from_string(const char *str)
This is the inverse function of av_channel_name().
Definition: channel_layout.c:141
channel_layout.h
av_channel_layout_index_from_channel
int av_channel_layout_index_from_channel(const AVChannelLayout *channel_layout, enum AVChannel channel)
Get the index of a given channel in a channel layout.
Definition: channel_layout.c:836
avfilter.h
init
static av_cold int init(AVFilterContext *ctx)
Definition: af_pan.c:93
AVFilterContext
An instance of a filter.
Definition: avfilter.h:415
av_channel_layout_copy
int av_channel_layout_copy(AVChannelLayout *dst, const AVChannelLayout *src)
Make a copy of a channel layout.
Definition: channel_layout.c:639
FF_DISABLE_DEPRECATION_WARNINGS
#define FF_DISABLE_DEPRECATION_WARNINGS
Definition: internal.h:81
av_strdup
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:280
MAX_CHANNELS
#define MAX_CHANNELS
Definition: af_pan.c:40
audio.h
av_free
#define av_free(p)
Definition: tableprint_vlc.h:33
PanContext
Definition: af_pan.c:42
parse_channel_name
static int parse_channel_name(char **arg, int *rchannel, int *rnamed)
Definition: af_pan.c:65
FILTER_OUTPUTS
#define FILTER_OUTPUTS(array)
Definition: internal.h:191
PanContext::gain
double gain[MAX_CHANNELS][MAX_CHANNELS]
Definition: af_pan.c:46
AVFILTER_DEFINE_CLASS
AVFILTER_DEFINE_CLASS(pan)
uninit
static av_cold void uninit(AVFilterContext *ctx)
Definition: af_pan.c:396
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
avstring.h
AV_OPT_TYPE_STRING
@ AV_OPT_TYPE_STRING
Definition: opt.h:229
snprintf
#define snprintf
Definition: snprintf.h:34