FFmpeg  5.1.2
channel_layout.h
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1 /*
2  * Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
3  * Copyright (c) 2008 Peter Ross
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #ifndef AVUTIL_CHANNEL_LAYOUT_H
23 #define AVUTIL_CHANNEL_LAYOUT_H
24 
25 #include <stdint.h>
26 #include <stdlib.h>
27 
28 #include "version.h"
29 #include "attributes.h"
30 
31 /**
32  * @file
33  * audio channel layout utility functions
34  */
35 
36 /**
37  * @addtogroup lavu_audio
38  * @{
39  */
40 
41 enum AVChannel {
42  ///< Invalid channel index
62  /** Stereo downmix. */
64  /** See above. */
76 
77  /** Channel is empty can be safely skipped. */
78  AV_CHAN_UNUSED = 0x200,
79 
80  /** Channel contains data, but its position is unknown. */
81  AV_CHAN_UNKNOWN = 0x300,
82 
83  /**
84  * Range of channels between AV_CHAN_AMBISONIC_BASE and
85  * AV_CHAN_AMBISONIC_END represent Ambisonic components using the ACN system.
86  *
87  * Given a channel id <i> between AV_CHAN_AMBISONIC_BASE and
88  * AV_CHAN_AMBISONIC_END (inclusive), the ACN index of the channel <n> is
89  * <n> = <i> - AV_CHAN_AMBISONIC_BASE.
90  *
91  * @note these values are only used for AV_CHANNEL_ORDER_CUSTOM channel
92  * orderings, the AV_CHANNEL_ORDER_AMBISONIC ordering orders the channels
93  * implicitly by their position in the stream.
94  */
96  // leave space for 1024 ids, which correspond to maximum order-32 harmonics,
97  // which should be enough for the foreseeable use cases
99 };
100 
102  /**
103  * Only the channel count is specified, without any further information
104  * about the channel order.
105  */
107  /**
108  * The native channel order, i.e. the channels are in the same order in
109  * which they are defined in the AVChannel enum. This supports up to 63
110  * different channels.
111  */
113  /**
114  * The channel order does not correspond to any other predefined order and
115  * is stored as an explicit map. For example, this could be used to support
116  * layouts with 64 or more channels, or with empty/skipped (AV_CHAN_SILENCE)
117  * channels at arbitrary positions.
118  */
120  /**
121  * The audio is represented as the decomposition of the sound field into
122  * spherical harmonics. Each channel corresponds to a single expansion
123  * component. Channels are ordered according to ACN (Ambisonic Channel
124  * Number).
125  *
126  * The channel with the index n in the stream contains the spherical
127  * harmonic of degree l and order m given by
128  * @code{.unparsed}
129  * l = floor(sqrt(n)),
130  * m = n - l * (l + 1).
131  * @endcode
132  *
133  * Conversely given a spherical harmonic of degree l and order m, the
134  * corresponding channel index n is given by
135  * @code{.unparsed}
136  * n = l * (l + 1) + m.
137  * @endcode
138  *
139  * Normalization is assumed to be SN3D (Schmidt Semi-Normalization)
140  * as defined in AmbiX format $ 2.1.
141  */
143 };
144 
145 
146 /**
147  * @defgroup channel_masks Audio channel masks
148  *
149  * A channel layout is a 64-bits integer with a bit set for every channel.
150  * The number of bits set must be equal to the number of channels.
151  * The value 0 means that the channel layout is not known.
152  * @note this data structure is not powerful enough to handle channels
153  * combinations that have the same channel multiple times, such as
154  * dual-mono.
155  *
156  * @{
157  */
158 #define AV_CH_FRONT_LEFT (1ULL << AV_CHAN_FRONT_LEFT )
159 #define AV_CH_FRONT_RIGHT (1ULL << AV_CHAN_FRONT_RIGHT )
160 #define AV_CH_FRONT_CENTER (1ULL << AV_CHAN_FRONT_CENTER )
161 #define AV_CH_LOW_FREQUENCY (1ULL << AV_CHAN_LOW_FREQUENCY )
162 #define AV_CH_BACK_LEFT (1ULL << AV_CHAN_BACK_LEFT )
163 #define AV_CH_BACK_RIGHT (1ULL << AV_CHAN_BACK_RIGHT )
164 #define AV_CH_FRONT_LEFT_OF_CENTER (1ULL << AV_CHAN_FRONT_LEFT_OF_CENTER )
165 #define AV_CH_FRONT_RIGHT_OF_CENTER (1ULL << AV_CHAN_FRONT_RIGHT_OF_CENTER)
166 #define AV_CH_BACK_CENTER (1ULL << AV_CHAN_BACK_CENTER )
167 #define AV_CH_SIDE_LEFT (1ULL << AV_CHAN_SIDE_LEFT )
168 #define AV_CH_SIDE_RIGHT (1ULL << AV_CHAN_SIDE_RIGHT )
169 #define AV_CH_TOP_CENTER (1ULL << AV_CHAN_TOP_CENTER )
170 #define AV_CH_TOP_FRONT_LEFT (1ULL << AV_CHAN_TOP_FRONT_LEFT )
171 #define AV_CH_TOP_FRONT_CENTER (1ULL << AV_CHAN_TOP_FRONT_CENTER )
172 #define AV_CH_TOP_FRONT_RIGHT (1ULL << AV_CHAN_TOP_FRONT_RIGHT )
173 #define AV_CH_TOP_BACK_LEFT (1ULL << AV_CHAN_TOP_BACK_LEFT )
174 #define AV_CH_TOP_BACK_CENTER (1ULL << AV_CHAN_TOP_BACK_CENTER )
175 #define AV_CH_TOP_BACK_RIGHT (1ULL << AV_CHAN_TOP_BACK_RIGHT )
176 #define AV_CH_STEREO_LEFT (1ULL << AV_CHAN_STEREO_LEFT )
177 #define AV_CH_STEREO_RIGHT (1ULL << AV_CHAN_STEREO_RIGHT )
178 #define AV_CH_WIDE_LEFT (1ULL << AV_CHAN_WIDE_LEFT )
179 #define AV_CH_WIDE_RIGHT (1ULL << AV_CHAN_WIDE_RIGHT )
180 #define AV_CH_SURROUND_DIRECT_LEFT (1ULL << AV_CHAN_SURROUND_DIRECT_LEFT )
181 #define AV_CH_SURROUND_DIRECT_RIGHT (1ULL << AV_CHAN_SURROUND_DIRECT_RIGHT)
182 #define AV_CH_LOW_FREQUENCY_2 (1ULL << AV_CHAN_LOW_FREQUENCY_2 )
183 #define AV_CH_TOP_SIDE_LEFT (1ULL << AV_CHAN_TOP_SIDE_LEFT )
184 #define AV_CH_TOP_SIDE_RIGHT (1ULL << AV_CHAN_TOP_SIDE_RIGHT )
185 #define AV_CH_BOTTOM_FRONT_CENTER (1ULL << AV_CHAN_BOTTOM_FRONT_CENTER )
186 #define AV_CH_BOTTOM_FRONT_LEFT (1ULL << AV_CHAN_BOTTOM_FRONT_LEFT )
187 #define AV_CH_BOTTOM_FRONT_RIGHT (1ULL << AV_CHAN_BOTTOM_FRONT_RIGHT )
188 
189 #if FF_API_OLD_CHANNEL_LAYOUT
190 /** Channel mask value used for AVCodecContext.request_channel_layout
191  to indicate that the user requests the channel order of the decoder output
192  to be the native codec channel order.
193  @deprecated channel order is now indicated in a special field in
194  AVChannelLayout
195  */
196 #define AV_CH_LAYOUT_NATIVE 0x8000000000000000ULL
197 #endif
198 
199 /**
200  * @}
201  * @defgroup channel_mask_c Audio channel layouts
202  * @{
203  * */
204 #define AV_CH_LAYOUT_MONO (AV_CH_FRONT_CENTER)
205 #define AV_CH_LAYOUT_STEREO (AV_CH_FRONT_LEFT|AV_CH_FRONT_RIGHT)
206 #define AV_CH_LAYOUT_2POINT1 (AV_CH_LAYOUT_STEREO|AV_CH_LOW_FREQUENCY)
207 #define AV_CH_LAYOUT_2_1 (AV_CH_LAYOUT_STEREO|AV_CH_BACK_CENTER)
208 #define AV_CH_LAYOUT_SURROUND (AV_CH_LAYOUT_STEREO|AV_CH_FRONT_CENTER)
209 #define AV_CH_LAYOUT_3POINT1 (AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY)
210 #define AV_CH_LAYOUT_4POINT0 (AV_CH_LAYOUT_SURROUND|AV_CH_BACK_CENTER)
211 #define AV_CH_LAYOUT_4POINT1 (AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY)
212 #define AV_CH_LAYOUT_2_2 (AV_CH_LAYOUT_STEREO|AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT)
213 #define AV_CH_LAYOUT_QUAD (AV_CH_LAYOUT_STEREO|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
214 #define AV_CH_LAYOUT_5POINT0 (AV_CH_LAYOUT_SURROUND|AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT)
215 #define AV_CH_LAYOUT_5POINT1 (AV_CH_LAYOUT_5POINT0|AV_CH_LOW_FREQUENCY)
216 #define AV_CH_LAYOUT_5POINT0_BACK (AV_CH_LAYOUT_SURROUND|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
217 #define AV_CH_LAYOUT_5POINT1_BACK (AV_CH_LAYOUT_5POINT0_BACK|AV_CH_LOW_FREQUENCY)
218 #define AV_CH_LAYOUT_6POINT0 (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_CENTER)
219 #define AV_CH_LAYOUT_6POINT0_FRONT (AV_CH_LAYOUT_2_2|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
220 #define AV_CH_LAYOUT_HEXAGONAL (AV_CH_LAYOUT_5POINT0_BACK|AV_CH_BACK_CENTER)
221 #define AV_CH_LAYOUT_6POINT1 (AV_CH_LAYOUT_5POINT1|AV_CH_BACK_CENTER)
222 #define AV_CH_LAYOUT_6POINT1_BACK (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_BACK_CENTER)
223 #define AV_CH_LAYOUT_6POINT1_FRONT (AV_CH_LAYOUT_6POINT0_FRONT|AV_CH_LOW_FREQUENCY)
224 #define AV_CH_LAYOUT_7POINT0 (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
225 #define AV_CH_LAYOUT_7POINT0_FRONT (AV_CH_LAYOUT_5POINT0|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
226 #define AV_CH_LAYOUT_7POINT1 (AV_CH_LAYOUT_5POINT1|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
227 #define AV_CH_LAYOUT_7POINT1_WIDE (AV_CH_LAYOUT_5POINT1|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
228 #define AV_CH_LAYOUT_7POINT1_WIDE_BACK (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
229 #define AV_CH_LAYOUT_OCTAGONAL (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_LEFT|AV_CH_BACK_CENTER|AV_CH_BACK_RIGHT)
230 #define AV_CH_LAYOUT_HEXADECAGONAL (AV_CH_LAYOUT_OCTAGONAL|AV_CH_WIDE_LEFT|AV_CH_WIDE_RIGHT|AV_CH_TOP_BACK_LEFT|AV_CH_TOP_BACK_RIGHT|AV_CH_TOP_BACK_CENTER|AV_CH_TOP_FRONT_CENTER|AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT)
231 #define AV_CH_LAYOUT_STEREO_DOWNMIX (AV_CH_STEREO_LEFT|AV_CH_STEREO_RIGHT)
232 #define AV_CH_LAYOUT_22POINT2 (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER|AV_CH_BACK_CENTER|AV_CH_LOW_FREQUENCY_2|AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT|AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT|AV_CH_TOP_FRONT_CENTER|AV_CH_TOP_CENTER|AV_CH_TOP_BACK_LEFT|AV_CH_TOP_BACK_RIGHT|AV_CH_TOP_SIDE_LEFT|AV_CH_TOP_SIDE_RIGHT|AV_CH_TOP_BACK_CENTER|AV_CH_BOTTOM_FRONT_CENTER|AV_CH_BOTTOM_FRONT_LEFT|AV_CH_BOTTOM_FRONT_RIGHT)
233 
243 };
244 
245 /**
246  * @}
247  */
248 
249 /**
250  * An AVChannelCustom defines a single channel within a custom order layout
251  *
252  * Unlike most structures in FFmpeg, sizeof(AVChannelCustom) is a part of the
253  * public ABI.
254  *
255  * No new fields may be added to it without a major version bump.
256  */
257 typedef struct AVChannelCustom {
258  enum AVChannel id;
259  char name[16];
260  void *opaque;
262 
263 /**
264  * An AVChannelLayout holds information about the channel layout of audio data.
265  *
266  * A channel layout here is defined as a set of channels ordered in a specific
267  * way (unless the channel order is AV_CHANNEL_ORDER_UNSPEC, in which case an
268  * AVChannelLayout carries only the channel count).
269  *
270  * Unlike most structures in Libav, sizeof(AVChannelLayout) is a part of the
271  * public ABI and may be used by the caller. E.g. it may be allocated on stack
272  * or embedded in caller-defined structs.
273  *
274  * AVChannelLayout can be initialized as follows:
275  * - default initialization with {0}, followed by setting all used fields
276  * correctly;
277  * - by assigning one of the predefined AV_CHANNEL_LAYOUT_* initializers;
278  * - with a constructor function, such as av_channel_layout_default(),
279  * av_channel_layout_from_mask() or av_channel_layout_from_string().
280  *
281  * The channel layout must be unitialized with av_channel_layout_uninit()
282  *
283  * Copying an AVChannelLayout via assigning is forbidden,
284  * av_channel_layout_copy() must be used instead (and its return value should
285  * be checked)
286  *
287  * No new fields may be added to it without a major version bump, except for
288  * new elements of the union fitting in sizeof(uint64_t).
289  */
290 typedef struct AVChannelLayout {
291  /**
292  * Channel order used in this layout.
293  * This is a mandatory field.
294  */
295  enum AVChannelOrder order;
296 
297  /**
298  * Number of channels in this layout. Mandatory field.
299  */
301 
302  /**
303  * Details about which channels are present in this layout.
304  * For AV_CHANNEL_ORDER_UNSPEC, this field is undefined and must not be
305  * used.
306  */
307  union {
308  /**
309  * This member must be used for AV_CHANNEL_ORDER_NATIVE, and may be used
310  * for AV_CHANNEL_ORDER_AMBISONIC to signal non-diegetic channels.
311  * It is a bitmask, where the position of each set bit means that the
312  * AVChannel with the corresponding value is present.
313  *
314  * I.e. when (mask & (1 << AV_CHAN_FOO)) is non-zero, then AV_CHAN_FOO
315  * is present in the layout. Otherwise it is not present.
316  *
317  * @note when a channel layout using a bitmask is constructed or
318  * modified manually (i.e. not using any of the av_channel_layout_*
319  * functions), the code doing it must ensure that the number of set bits
320  * is equal to nb_channels.
321  */
322  uint64_t mask;
323  /**
324  * This member must be used when the channel order is
325  * AV_CHANNEL_ORDER_CUSTOM. It is a nb_channels-sized array, with each
326  * element signalling the presence of the AVChannel with the
327  * corresponding value in map[i].id.
328  *
329  * I.e. when map[i].id is equal to AV_CHAN_FOO, then AV_CH_FOO is the
330  * i-th channel in the audio data.
331  *
332  * When map[i].id is in the range between AV_CHAN_AMBISONIC_BASE and
333  * AV_CHAN_AMBISONIC_END (inclusive), the channel contains an ambisonic
334  * component with ACN index (as defined above)
335  * n = map[i].id - AV_CHAN_AMBISONIC_BASE.
336  *
337  * map[i].name may be filled with a 0-terminated string, in which case
338  * it will be used for the purpose of identifying the channel with the
339  * convenience functions below. Otherise it must be zeroed.
340  */
342  } u;
343 
344  /**
345  * For some private data of the user.
346  */
347  void *opaque;
349 
350 #define AV_CHANNEL_LAYOUT_MASK(nb, m) \
351  { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = (nb), .u = { .mask = (m) }}
352 
353 #define AV_CHANNEL_LAYOUT_MONO AV_CHANNEL_LAYOUT_MASK(1, AV_CH_LAYOUT_MONO)
354 #define AV_CHANNEL_LAYOUT_STEREO AV_CHANNEL_LAYOUT_MASK(2, AV_CH_LAYOUT_STEREO)
355 #define AV_CHANNEL_LAYOUT_2POINT1 AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_2POINT1)
356 #define AV_CHANNEL_LAYOUT_2_1 AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_2_1)
357 #define AV_CHANNEL_LAYOUT_SURROUND AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_SURROUND)
358 #define AV_CHANNEL_LAYOUT_3POINT1 AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_3POINT1)
359 #define AV_CHANNEL_LAYOUT_4POINT0 AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_4POINT0)
360 #define AV_CHANNEL_LAYOUT_4POINT1 AV_CHANNEL_LAYOUT_MASK(5, AV_CH_LAYOUT_4POINT1)
361 #define AV_CHANNEL_LAYOUT_2_2 AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_2_2)
362 #define AV_CHANNEL_LAYOUT_QUAD AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_QUAD)
363 #define AV_CHANNEL_LAYOUT_5POINT0 AV_CHANNEL_LAYOUT_MASK(5, AV_CH_LAYOUT_5POINT0)
364 #define AV_CHANNEL_LAYOUT_5POINT1 AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_5POINT1)
365 #define AV_CHANNEL_LAYOUT_5POINT0_BACK AV_CHANNEL_LAYOUT_MASK(5, AV_CH_LAYOUT_5POINT0_BACK)
366 #define AV_CHANNEL_LAYOUT_5POINT1_BACK AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_5POINT1_BACK)
367 #define AV_CHANNEL_LAYOUT_6POINT0 AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_6POINT0)
368 #define AV_CHANNEL_LAYOUT_6POINT0_FRONT AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_6POINT0_FRONT)
369 #define AV_CHANNEL_LAYOUT_HEXAGONAL AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_HEXAGONAL)
370 #define AV_CHANNEL_LAYOUT_6POINT1 AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_6POINT1)
371 #define AV_CHANNEL_LAYOUT_6POINT1_BACK AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_6POINT1_BACK)
372 #define AV_CHANNEL_LAYOUT_6POINT1_FRONT AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_6POINT1_FRONT)
373 #define AV_CHANNEL_LAYOUT_7POINT0 AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_7POINT0)
374 #define AV_CHANNEL_LAYOUT_7POINT0_FRONT AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_7POINT0_FRONT)
375 #define AV_CHANNEL_LAYOUT_7POINT1 AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_7POINT1)
376 #define AV_CHANNEL_LAYOUT_7POINT1_WIDE AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_7POINT1_WIDE)
377 #define AV_CHANNEL_LAYOUT_7POINT1_WIDE_BACK AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_7POINT1_WIDE_BACK)
378 #define AV_CHANNEL_LAYOUT_OCTAGONAL AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_OCTAGONAL)
379 #define AV_CHANNEL_LAYOUT_HEXADECAGONAL AV_CHANNEL_LAYOUT_MASK(16, AV_CH_LAYOUT_HEXADECAGONAL)
380 #define AV_CHANNEL_LAYOUT_STEREO_DOWNMIX AV_CHANNEL_LAYOUT_MASK(2, AV_CH_LAYOUT_STEREO_DOWNMIX)
381 #define AV_CHANNEL_LAYOUT_22POINT2 AV_CHANNEL_LAYOUT_MASK(24, AV_CH_LAYOUT_22POINT2)
382 #define AV_CHANNEL_LAYOUT_AMBISONIC_FIRST_ORDER \
383  { .order = AV_CHANNEL_ORDER_AMBISONIC, .nb_channels = 4, .u = { .mask = 0 }}
384 
385 struct AVBPrint;
386 
387 #if FF_API_OLD_CHANNEL_LAYOUT
388 /**
389  * Return a channel layout id that matches name, or 0 if no match is found.
390  *
391  * name can be one or several of the following notations,
392  * separated by '+' or '|':
393  * - the name of an usual channel layout (mono, stereo, 4.0, quad, 5.0,
394  * 5.0(side), 5.1, 5.1(side), 7.1, 7.1(wide), downmix);
395  * - the name of a single channel (FL, FR, FC, LFE, BL, BR, FLC, FRC, BC,
396  * SL, SR, TC, TFL, TFC, TFR, TBL, TBC, TBR, DL, DR);
397  * - a number of channels, in decimal, followed by 'c', yielding
398  * the default channel layout for that number of channels (@see
399  * av_get_default_channel_layout);
400  * - a channel layout mask, in hexadecimal starting with "0x" (see the
401  * AV_CH_* macros).
402  *
403  * Example: "stereo+FC" = "2c+FC" = "2c+1c" = "0x7"
404  *
405  * @deprecated use av_channel_layout_from_string()
406  */
408 uint64_t av_get_channel_layout(const char *name);
409 
410 /**
411  * Return a channel layout and the number of channels based on the specified name.
412  *
413  * This function is similar to (@see av_get_channel_layout), but can also parse
414  * unknown channel layout specifications.
415  *
416  * @param[in] name channel layout specification string
417  * @param[out] channel_layout parsed channel layout (0 if unknown)
418  * @param[out] nb_channels number of channels
419  *
420  * @return 0 on success, AVERROR(EINVAL) if the parsing fails.
421  * @deprecated use av_channel_layout_from_string()
422  */
424 int av_get_extended_channel_layout(const char *name, uint64_t* channel_layout, int* nb_channels);
425 
426 /**
427  * Return a description of a channel layout.
428  * If nb_channels is <= 0, it is guessed from the channel_layout.
429  *
430  * @param buf put here the string containing the channel layout
431  * @param buf_size size in bytes of the buffer
432  * @deprecated use av_channel_layout_describe()
433  */
435 void av_get_channel_layout_string(char *buf, int buf_size, int nb_channels, uint64_t channel_layout);
436 
437 /**
438  * Append a description of a channel layout to a bprint buffer.
439  * @deprecated use av_channel_layout_describe()
440  */
442 void av_bprint_channel_layout(struct AVBPrint *bp, int nb_channels, uint64_t channel_layout);
443 
444 /**
445  * Return the number of channels in the channel layout.
446  * @deprecated use AVChannelLayout.nb_channels
447  */
449 int av_get_channel_layout_nb_channels(uint64_t channel_layout);
450 
451 /**
452  * Return default channel layout for a given number of channels.
453  *
454  * @deprecated use av_channel_layout_default()
455  */
457 int64_t av_get_default_channel_layout(int nb_channels);
458 
459 /**
460  * Get the index of a channel in channel_layout.
461  *
462  * @param channel a channel layout describing exactly one channel which must be
463  * present in channel_layout.
464  *
465  * @return index of channel in channel_layout on success, a negative AVERROR
466  * on error.
467  *
468  * @deprecated use av_channel_layout_index_from_channel()
469  */
471 int av_get_channel_layout_channel_index(uint64_t channel_layout,
472  uint64_t channel);
473 
474 /**
475  * Get the channel with the given index in channel_layout.
476  * @deprecated use av_channel_layout_channel_from_index()
477  */
479 uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index);
480 
481 /**
482  * Get the name of a given channel.
483  *
484  * @return channel name on success, NULL on error.
485  *
486  * @deprecated use av_channel_name()
487  */
489 const char *av_get_channel_name(uint64_t channel);
490 
491 /**
492  * Get the description of a given channel.
493  *
494  * @param channel a channel layout with a single channel
495  * @return channel description on success, NULL on error
496  * @deprecated use av_channel_description()
497  */
499 const char *av_get_channel_description(uint64_t channel);
500 
501 /**
502  * Get the value and name of a standard channel layout.
503  *
504  * @param[in] index index in an internal list, starting at 0
505  * @param[out] layout channel layout mask
506  * @param[out] name name of the layout
507  * @return 0 if the layout exists,
508  * <0 if index is beyond the limits
509  * @deprecated use av_channel_layout_standard()
510  */
512 int av_get_standard_channel_layout(unsigned index, uint64_t *layout,
513  const char **name);
514 #endif
515 
516 /**
517  * Get a human readable string in an abbreviated form describing a given channel.
518  * This is the inverse function of @ref av_channel_from_string().
519  *
520  * @param buf pre-allocated buffer where to put the generated string
521  * @param buf_size size in bytes of the buffer.
522  * @return amount of bytes needed to hold the output string, or a negative AVERROR
523  * on failure. If the returned value is bigger than buf_size, then the
524  * string was truncated.
525  */
526 int av_channel_name(char *buf, size_t buf_size, enum AVChannel channel);
527 
528 /**
529  * bprint variant of av_channel_name().
530  *
531  * @note the string will be appended to the bprint buffer.
532  */
533 void av_channel_name_bprint(struct AVBPrint *bp, enum AVChannel channel_id);
534 
535 /**
536  * Get a human readable string describing a given channel.
537  *
538  * @param buf pre-allocated buffer where to put the generated string
539  * @param buf_size size in bytes of the buffer.
540  * @return amount of bytes needed to hold the output string, or a negative AVERROR
541  * on failure. If the returned value is bigger than buf_size, then the
542  * string was truncated.
543  */
544 int av_channel_description(char *buf, size_t buf_size, enum AVChannel channel);
545 
546 /**
547  * bprint variant of av_channel_description().
548  *
549  * @note the string will be appended to the bprint buffer.
550  */
551 void av_channel_description_bprint(struct AVBPrint *bp, enum AVChannel channel_id);
552 
553 /**
554  * This is the inverse function of @ref av_channel_name().
555  *
556  * @return the channel with the given name
557  * AV_CHAN_NONE when name does not identify a known channel
558  */
559 enum AVChannel av_channel_from_string(const char *name);
560 
561 /**
562  * Initialize a native channel layout from a bitmask indicating which channels
563  * are present.
564  *
565  * @param channel_layout the layout structure to be initialized
566  * @param mask bitmask describing the channel layout
567  *
568  * @return 0 on success
569  * AVERROR(EINVAL) for invalid mask values
570  */
571 int av_channel_layout_from_mask(AVChannelLayout *channel_layout, uint64_t mask);
572 
573 /**
574  * Initialize a channel layout from a given string description.
575  * The input string can be represented by:
576  * - the formal channel layout name (returned by av_channel_layout_describe())
577  * - single or multiple channel names (returned by av_channel_name(), eg. "FL",
578  * or concatenated with "+", each optionally containing a custom name after
579  * a "@", eg. "FL@Left+FR@Right+LFE")
580  * - a decimal or hexadecimal value of a native channel layout (eg. "4" or "0x4")
581  * - the number of channels with default layout (eg. "4c")
582  * - the number of unordered channels (eg. "4C" or "4 channels")
583  * - the ambisonic order followed by optional non-diegetic channels (eg.
584  * "ambisonic 2+stereo")
585  *
586  * @param channel_layout input channel layout
587  * @param str string describing the channel layout
588  * @return 0 channel layout was detected, AVERROR_INVALIDATATA otherwise
589  */
591  const char *str);
592 
593 /**
594  * Get the default channel layout for a given number of channels.
595  *
596  * @param channel_layout the layout structure to be initialized
597  * @param nb_channels number of channels
598  */
599 void av_channel_layout_default(AVChannelLayout *ch_layout, int nb_channels);
600 
601 /**
602  * Iterate over all standard channel layouts.
603  *
604  * @param opaque a pointer where libavutil will store the iteration state. Must
605  * point to NULL to start the iteration.
606  *
607  * @return the standard channel layout or NULL when the iteration is
608  * finished
609  */
611 
612 /**
613  * Free any allocated data in the channel layout and reset the channel
614  * count to 0.
615  *
616  * @param channel_layout the layout structure to be uninitialized
617  */
619 
620 /**
621  * Make a copy of a channel layout. This differs from just assigning src to dst
622  * in that it allocates and copies the map for AV_CHANNEL_ORDER_CUSTOM.
623  *
624  * @note the destination channel_layout will be always uninitialized before copy.
625  *
626  * @param dst destination channel layout
627  * @param src source channel layout
628  * @return 0 on success, a negative AVERROR on error.
629  */
631 
632 /**
633  * Get a human-readable string describing the channel layout properties.
634  * The string will be in the same format that is accepted by
635  * @ref av_channel_layout_from_string(), allowing to rebuild the same
636  * channel layout, except for opaque pointers.
637  *
638  * @param channel_layout channel layout to be described
639  * @param buf pre-allocated buffer where to put the generated string
640  * @param buf_size size in bytes of the buffer.
641  * @return amount of bytes needed to hold the output string, or a negative AVERROR
642  * on failure. If the returned value is bigger than buf_size, then the
643  * string was truncated.
644  */
645 int av_channel_layout_describe(const AVChannelLayout *channel_layout,
646  char *buf, size_t buf_size);
647 
648 /**
649  * bprint variant of av_channel_layout_describe().
650  *
651  * @note the string will be appended to the bprint buffer.
652  * @return 0 on success, or a negative AVERROR value on failure.
653  */
655  struct AVBPrint *bp);
656 
657 /**
658  * Get the channel with the given index in a channel layout.
659  *
660  * @param channel_layout input channel layout
661  * @return channel with the index idx in channel_layout on success or
662  * AV_CHAN_NONE on failure (if idx is not valid or the channel order is
663  * unspecified)
664  */
665 enum AVChannel
666 av_channel_layout_channel_from_index(const AVChannelLayout *channel_layout, unsigned int idx);
667 
668 /**
669  * Get the index of a given channel in a channel layout. In case multiple
670  * channels are found, only the first match will be returned.
671  *
672  * @param channel_layout input channel layout
673  * @return index of channel in channel_layout on success or a negative number if
674  * channel is not present in channel_layout.
675  */
677  enum AVChannel channel);
678 
679 /**
680  * Get the index in a channel layout of a channel described by the given string.
681  * In case multiple channels are found, only the first match will be returned.
682  *
683  * This function accepts channel names in the same format as
684  * @ref av_channel_from_string().
685  *
686  * @param channel_layout input channel layout
687  * @return a channel index described by the given string, or a negative AVERROR
688  * value.
689  */
691  const char *name);
692 
693 /**
694  * Get a channel described by the given string.
695  *
696  * This function accepts channel names in the same format as
697  * @ref av_channel_from_string().
698  *
699  * @param channel_layout input channel layout
700  * @return a channel described by the given string in channel_layout on success
701  * or AV_CHAN_NONE on failure (if the string is not valid or the channel
702  * order is unspecified)
703  */
704 enum AVChannel
706  const char *name);
707 
708 /**
709  * Find out what channels from a given set are present in a channel layout,
710  * without regard for their positions.
711  *
712  * @param channel_layout input channel layout
713  * @param mask a combination of AV_CH_* representing a set of channels
714  * @return a bitfield representing all the channels from mask that are present
715  * in channel_layout
716  */
717 uint64_t av_channel_layout_subset(const AVChannelLayout *channel_layout,
718  uint64_t mask);
719 
720 /**
721  * Check whether a channel layout is valid, i.e. can possibly describe audio
722  * data.
723  *
724  * @param channel_layout input channel layout
725  * @return 1 if channel_layout is valid, 0 otherwise.
726  */
727 int av_channel_layout_check(const AVChannelLayout *channel_layout);
728 
729 /**
730  * Check whether two channel layouts are semantically the same, i.e. the same
731  * channels are present on the same positions in both.
732  *
733  * If one of the channel layouts is AV_CHANNEL_ORDER_UNSPEC, while the other is
734  * not, they are considered to be unequal. If both are AV_CHANNEL_ORDER_UNSPEC,
735  * they are considered equal iff the channel counts are the same in both.
736  *
737  * @param chl input channel layout
738  * @param chl1 input channel layout
739  * @return 0 if chl and chl1 are equal, 1 if they are not equal. A negative
740  * AVERROR code if one or both are invalid.
741  */
743 
744 /**
745  * @}
746  * @}
747  */
748 
749 #endif /* AVUTIL_CHANNEL_LAYOUT_H */
Macro definitions for various function/variable attributes.
#define attribute_deprecated
Definition: attributes.h:100
AVMatrixEncoding
@ AV_MATRIX_ENCODING_DPLIIX
@ AV_MATRIX_ENCODING_NONE
@ AV_MATRIX_ENCODING_DOLBY
@ AV_MATRIX_ENCODING_DPLII
@ AV_MATRIX_ENCODING_NB
@ AV_MATRIX_ENCODING_DPLIIZ
@ AV_MATRIX_ENCODING_DOLBYEX
@ AV_MATRIX_ENCODING_DOLBYHEADPHONE
void av_channel_layout_default(AVChannelLayout *ch_layout, int nb_channels)
Get the default channel layout for a given number of channels.
enum AVChannel av_channel_layout_channel_from_string(const AVChannelLayout *channel_layout, const char *name)
Get a channel described by the given string.
attribute_deprecated const char * av_get_channel_description(uint64_t channel)
Get the description of a given channel.
attribute_deprecated int av_get_extended_channel_layout(const char *name, uint64_t *channel_layout, int *nb_channels)
Return a channel layout and the number of channels based on the specified name.
int av_channel_layout_from_string(AVChannelLayout *channel_layout, const char *str)
Initialize a channel layout from a given string description.
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.
attribute_deprecated int av_get_standard_channel_layout(unsigned index, uint64_t *layout, const char **name)
Get the value and name of a standard channel layout.
AVChannelOrder
int av_channel_layout_index_from_string(const AVChannelLayout *channel_layout, const char *name)
Get the index in a channel layout of a channel described by the given string.
attribute_deprecated void av_get_channel_layout_string(char *buf, int buf_size, int nb_channels, uint64_t channel_layout)
Return a description of a channel layout.
int av_channel_layout_describe_bprint(const AVChannelLayout *channel_layout, struct AVBPrint *bp)
bprint variant of av_channel_layout_describe().
void av_channel_description_bprint(struct AVBPrint *bp, enum AVChannel channel_id)
bprint variant of av_channel_description().
int av_channel_layout_compare(const AVChannelLayout *chl, const AVChannelLayout *chl1)
Check whether two channel layouts are semantically the same, i.e.
int av_channel_name(char *buf, size_t buf_size, enum AVChannel channel)
Get a human readable string in an abbreviated form describing a given channel.
int av_channel_description(char *buf, size_t buf_size, enum AVChannel channel)
Get a human readable string describing a given channel.
attribute_deprecated int av_get_channel_layout_channel_index(uint64_t channel_layout, uint64_t channel)
Get the index of a channel in channel_layout.
enum AVChannel av_channel_layout_channel_from_index(const AVChannelLayout *channel_layout, unsigned int idx)
Get the channel with the given index in a channel layout.
attribute_deprecated const char * av_get_channel_name(uint64_t channel)
Get the name of a given channel.
void av_channel_layout_uninit(AVChannelLayout *channel_layout)
Free any allocated data in the channel layout and reset the channel count to 0.
attribute_deprecated uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index)
Get the channel with the given index in channel_layout.
AVChannel
attribute_deprecated int av_get_channel_layout_nb_channels(uint64_t channel_layout)
Return the number of channels in the channel layout.
void av_channel_name_bprint(struct AVBPrint *bp, enum AVChannel channel_id)
bprint variant of av_channel_name().
attribute_deprecated void av_bprint_channel_layout(struct AVBPrint *bp, int nb_channels, uint64_t channel_layout)
Append a description of a channel layout to a bprint buffer.
int av_channel_layout_from_mask(AVChannelLayout *channel_layout, uint64_t mask)
Initialize a native channel layout from a bitmask indicating which channels are present.
attribute_deprecated int64_t av_get_default_channel_layout(int nb_channels)
Return default channel layout for a given number of channels.
int av_channel_layout_describe(const AVChannelLayout *channel_layout, char *buf, size_t buf_size)
Get a human-readable string describing the channel layout properties.
int av_channel_layout_check(const AVChannelLayout *channel_layout)
Check whether a channel layout is valid, i.e.
int av_channel_layout_copy(AVChannelLayout *dst, const AVChannelLayout *src)
Make a copy of a channel layout.
attribute_deprecated uint64_t av_get_channel_layout(const char *name)
Return a channel layout id that matches name, or 0 if no match is found.
uint64_t av_channel_layout_subset(const AVChannelLayout *channel_layout, uint64_t mask)
Find out what channels from a given set are present in a channel layout, without regard for their pos...
enum AVChannel av_channel_from_string(const char *name)
This is the inverse function of av_channel_name().
const AVChannelLayout * av_channel_layout_standard(void **opaque)
Iterate over all standard channel layouts.
@ AV_CHANNEL_ORDER_NATIVE
The native channel order, i.e.
@ AV_CHANNEL_ORDER_CUSTOM
The channel order does not correspond to any other predefined order and is stored as an explicit map.
@ AV_CHANNEL_ORDER_UNSPEC
Only the channel count is specified, without any further information about the channel order.
@ AV_CHANNEL_ORDER_AMBISONIC
The audio is represented as the decomposition of the sound field into spherical harmonics.
@ AV_CHAN_LOW_FREQUENCY
@ AV_CHAN_BACK_RIGHT
@ AV_CHAN_UNUSED
Channel is empty can be safely skipped.
@ AV_CHAN_FRONT_RIGHT_OF_CENTER
@ AV_CHAN_FRONT_LEFT
@ AV_CHAN_TOP_BACK_LEFT
@ AV_CHAN_TOP_FRONT_RIGHT
@ AV_CHAN_FRONT_RIGHT
@ AV_CHAN_AMBISONIC_BASE
Range of channels between AV_CHAN_AMBISONIC_BASE and AV_CHAN_AMBISONIC_END represent Ambisonic compon...
@ AV_CHAN_BACK_CENTER
@ AV_CHAN_TOP_SIDE_RIGHT
@ AV_CHAN_FRONT_CENTER
@ AV_CHAN_SIDE_RIGHT
@ AV_CHAN_WIDE_LEFT
@ AV_CHAN_FRONT_LEFT_OF_CENTER
@ AV_CHAN_NONE
Invalid channel index.
@ AV_CHAN_LOW_FREQUENCY_2
@ AV_CHAN_TOP_BACK_CENTER
@ AV_CHAN_BACK_LEFT
@ AV_CHAN_UNKNOWN
Channel contains data, but its position is unknown.
@ AV_CHAN_SIDE_LEFT
@ AV_CHAN_SURROUND_DIRECT_RIGHT
@ AV_CHAN_BOTTOM_FRONT_CENTER
@ AV_CHAN_TOP_FRONT_LEFT
@ AV_CHAN_TOP_BACK_RIGHT
@ AV_CHAN_BOTTOM_FRONT_RIGHT
@ AV_CHAN_STEREO_RIGHT
See above.
@ AV_CHAN_AMBISONIC_END
@ AV_CHAN_TOP_SIDE_LEFT
@ AV_CHAN_WIDE_RIGHT
@ AV_CHAN_BOTTOM_FRONT_LEFT
@ AV_CHAN_SURROUND_DIRECT_LEFT
@ AV_CHAN_TOP_CENTER
@ AV_CHAN_STEREO_LEFT
Stereo downmix.
@ AV_CHAN_TOP_FRONT_CENTER
Libavutil version macros.
An AVChannelCustom defines a single channel within a custom order layout.
enum AVChannel id
An AVChannelLayout holds information about the channel layout of audio data.
enum AVChannelOrder order
Channel order used in this layout.
uint64_t mask
This member must be used for AV_CHANNEL_ORDER_NATIVE, and may be used for AV_CHANNEL_ORDER_AMBISONIC ...
union AVChannelLayout::@5 u
Details about which channels are present in this layout.
int nb_channels
Number of channels in this layout.
void * opaque
For some private data of the user.
AVChannelCustom * map
This member must be used when the channel order is AV_CHANNEL_ORDER_CUSTOM.