FFmpeg 7.1.1
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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 * @ingroup lavu_audio_channels
34 * Public libavutil channel layout APIs header.
35 */
36
37
38/**
39 * @defgroup lavu_audio_channels Audio channels
40 * @ingroup lavu_audio
41 *
42 * Audio channel layout utility functions
43 *
44 * @{
45 */
46
48 ///< Invalid channel index
68 /** Stereo downmix. */
70 /** See above. */
82 AV_CHAN_SIDE_SURROUND_LEFT, ///< +90 degrees, Lss, SiL
83 AV_CHAN_SIDE_SURROUND_RIGHT, ///< -90 degrees, Rss, SiR
84 AV_CHAN_TOP_SURROUND_LEFT, ///< +110 degrees, Lvs, TpLS
85 AV_CHAN_TOP_SURROUND_RIGHT, ///< -110 degrees, Rvs, TpRS
86
87 /** Channel is empty can be safely skipped. */
89
90 /** Channel contains data, but its position is unknown. */
92
93 /**
94 * Range of channels between AV_CHAN_AMBISONIC_BASE and
95 * AV_CHAN_AMBISONIC_END represent Ambisonic components using the ACN system.
96 *
97 * Given a channel id `<i>` between AV_CHAN_AMBISONIC_BASE and
98 * AV_CHAN_AMBISONIC_END (inclusive), the ACN index of the channel `<n>` is
99 * `<n> = <i> - AV_CHAN_AMBISONIC_BASE`.
100 *
101 * @note these values are only used for AV_CHANNEL_ORDER_CUSTOM channel
102 * orderings, the AV_CHANNEL_ORDER_AMBISONIC ordering orders the channels
103 * implicitly by their position in the stream.
104 */
106 // leave space for 1024 ids, which correspond to maximum order-32 harmonics,
107 // which should be enough for the foreseeable use cases
109};
110
112 /**
113 * Only the channel count is specified, without any further information
114 * about the channel order.
115 */
117 /**
118 * The native channel order, i.e. the channels are in the same order in
119 * which they are defined in the AVChannel enum. This supports up to 63
120 * different channels.
121 */
123 /**
124 * The channel order does not correspond to any other predefined order and
125 * is stored as an explicit map. For example, this could be used to support
126 * layouts with 64 or more channels, or with empty/skipped (AV_CHAN_UNUSED)
127 * channels at arbitrary positions.
128 */
130 /**
131 * The audio is represented as the decomposition of the sound field into
132 * spherical harmonics. Each channel corresponds to a single expansion
133 * component. Channels are ordered according to ACN (Ambisonic Channel
134 * Number).
135 *
136 * The channel with the index n in the stream contains the spherical
137 * harmonic of degree l and order m given by
138 * @code{.unparsed}
139 * l = floor(sqrt(n)),
140 * m = n - l * (l + 1).
141 * @endcode
142 *
143 * Conversely given a spherical harmonic of degree l and order m, the
144 * corresponding channel index n is given by
145 * @code{.unparsed}
146 * n = l * (l + 1) + m.
147 * @endcode
148 *
149 * Normalization is assumed to be SN3D (Schmidt Semi-Normalization)
150 * as defined in AmbiX format $ 2.1.
151 */
153 /**
154 * Number of channel orders, not part of ABI/API
155 */
158
159
160/**
161 * @defgroup channel_masks Audio channel masks
162 *
163 * A channel layout is a 64-bits integer with a bit set for every channel.
164 * The number of bits set must be equal to the number of channels.
165 * The value 0 means that the channel layout is not known.
166 * @note this data structure is not powerful enough to handle channels
167 * combinations that have the same channel multiple times, such as
168 * dual-mono.
169 *
170 * @{
171 */
172#define AV_CH_FRONT_LEFT (1ULL << AV_CHAN_FRONT_LEFT )
173#define AV_CH_FRONT_RIGHT (1ULL << AV_CHAN_FRONT_RIGHT )
174#define AV_CH_FRONT_CENTER (1ULL << AV_CHAN_FRONT_CENTER )
175#define AV_CH_LOW_FREQUENCY (1ULL << AV_CHAN_LOW_FREQUENCY )
176#define AV_CH_BACK_LEFT (1ULL << AV_CHAN_BACK_LEFT )
177#define AV_CH_BACK_RIGHT (1ULL << AV_CHAN_BACK_RIGHT )
178#define AV_CH_FRONT_LEFT_OF_CENTER (1ULL << AV_CHAN_FRONT_LEFT_OF_CENTER )
179#define AV_CH_FRONT_RIGHT_OF_CENTER (1ULL << AV_CHAN_FRONT_RIGHT_OF_CENTER)
180#define AV_CH_BACK_CENTER (1ULL << AV_CHAN_BACK_CENTER )
181#define AV_CH_SIDE_LEFT (1ULL << AV_CHAN_SIDE_LEFT )
182#define AV_CH_SIDE_RIGHT (1ULL << AV_CHAN_SIDE_RIGHT )
183#define AV_CH_TOP_CENTER (1ULL << AV_CHAN_TOP_CENTER )
184#define AV_CH_TOP_FRONT_LEFT (1ULL << AV_CHAN_TOP_FRONT_LEFT )
185#define AV_CH_TOP_FRONT_CENTER (1ULL << AV_CHAN_TOP_FRONT_CENTER )
186#define AV_CH_TOP_FRONT_RIGHT (1ULL << AV_CHAN_TOP_FRONT_RIGHT )
187#define AV_CH_TOP_BACK_LEFT (1ULL << AV_CHAN_TOP_BACK_LEFT )
188#define AV_CH_TOP_BACK_CENTER (1ULL << AV_CHAN_TOP_BACK_CENTER )
189#define AV_CH_TOP_BACK_RIGHT (1ULL << AV_CHAN_TOP_BACK_RIGHT )
190#define AV_CH_STEREO_LEFT (1ULL << AV_CHAN_STEREO_LEFT )
191#define AV_CH_STEREO_RIGHT (1ULL << AV_CHAN_STEREO_RIGHT )
192#define AV_CH_WIDE_LEFT (1ULL << AV_CHAN_WIDE_LEFT )
193#define AV_CH_WIDE_RIGHT (1ULL << AV_CHAN_WIDE_RIGHT )
194#define AV_CH_SURROUND_DIRECT_LEFT (1ULL << AV_CHAN_SURROUND_DIRECT_LEFT )
195#define AV_CH_SURROUND_DIRECT_RIGHT (1ULL << AV_CHAN_SURROUND_DIRECT_RIGHT)
196#define AV_CH_LOW_FREQUENCY_2 (1ULL << AV_CHAN_LOW_FREQUENCY_2 )
197#define AV_CH_TOP_SIDE_LEFT (1ULL << AV_CHAN_TOP_SIDE_LEFT )
198#define AV_CH_TOP_SIDE_RIGHT (1ULL << AV_CHAN_TOP_SIDE_RIGHT )
199#define AV_CH_BOTTOM_FRONT_CENTER (1ULL << AV_CHAN_BOTTOM_FRONT_CENTER )
200#define AV_CH_BOTTOM_FRONT_LEFT (1ULL << AV_CHAN_BOTTOM_FRONT_LEFT )
201#define AV_CH_BOTTOM_FRONT_RIGHT (1ULL << AV_CHAN_BOTTOM_FRONT_RIGHT )
202#define AV_CH_SIDE_SURROUND_LEFT (1ULL << AV_CHAN_SIDE_SURROUND_LEFT )
203#define AV_CH_SIDE_SURROUND_RIGHT (1ULL << AV_CHAN_SIDE_SURROUND_RIGHT )
204#define AV_CH_TOP_SURROUND_LEFT (1ULL << AV_CHAN_TOP_SURROUND_LEFT )
205#define AV_CH_TOP_SURROUND_RIGHT (1ULL << AV_CHAN_TOP_SURROUND_RIGHT )
206
207/**
208 * @}
209 * @defgroup channel_mask_c Audio channel layouts
210 * @{
211 * */
212#define AV_CH_LAYOUT_MONO (AV_CH_FRONT_CENTER)
213#define AV_CH_LAYOUT_STEREO (AV_CH_FRONT_LEFT|AV_CH_FRONT_RIGHT)
214#define AV_CH_LAYOUT_2POINT1 (AV_CH_LAYOUT_STEREO|AV_CH_LOW_FREQUENCY)
215#define AV_CH_LAYOUT_2_1 (AV_CH_LAYOUT_STEREO|AV_CH_BACK_CENTER)
216#define AV_CH_LAYOUT_SURROUND (AV_CH_LAYOUT_STEREO|AV_CH_FRONT_CENTER)
217#define AV_CH_LAYOUT_3POINT1 (AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY)
218#define AV_CH_LAYOUT_4POINT0 (AV_CH_LAYOUT_SURROUND|AV_CH_BACK_CENTER)
219#define AV_CH_LAYOUT_4POINT1 (AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY)
220#define AV_CH_LAYOUT_2_2 (AV_CH_LAYOUT_STEREO|AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT)
221#define AV_CH_LAYOUT_QUAD (AV_CH_LAYOUT_STEREO|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
222#define AV_CH_LAYOUT_5POINT0 (AV_CH_LAYOUT_SURROUND|AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT)
223#define AV_CH_LAYOUT_5POINT1 (AV_CH_LAYOUT_5POINT0|AV_CH_LOW_FREQUENCY)
224#define AV_CH_LAYOUT_5POINT0_BACK (AV_CH_LAYOUT_SURROUND|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
225#define AV_CH_LAYOUT_5POINT1_BACK (AV_CH_LAYOUT_5POINT0_BACK|AV_CH_LOW_FREQUENCY)
226#define AV_CH_LAYOUT_6POINT0 (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_CENTER)
227#define AV_CH_LAYOUT_6POINT0_FRONT (AV_CH_LAYOUT_2_2|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
228#define AV_CH_LAYOUT_HEXAGONAL (AV_CH_LAYOUT_5POINT0_BACK|AV_CH_BACK_CENTER)
229#define AV_CH_LAYOUT_3POINT1POINT2 (AV_CH_LAYOUT_3POINT1|AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT)
230#define AV_CH_LAYOUT_6POINT1 (AV_CH_LAYOUT_5POINT1|AV_CH_BACK_CENTER)
231#define AV_CH_LAYOUT_6POINT1_BACK (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_BACK_CENTER)
232#define AV_CH_LAYOUT_6POINT1_FRONT (AV_CH_LAYOUT_6POINT0_FRONT|AV_CH_LOW_FREQUENCY)
233#define AV_CH_LAYOUT_7POINT0 (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
234#define AV_CH_LAYOUT_7POINT0_FRONT (AV_CH_LAYOUT_5POINT0|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
235#define AV_CH_LAYOUT_7POINT1 (AV_CH_LAYOUT_5POINT1|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
236#define AV_CH_LAYOUT_7POINT1_WIDE (AV_CH_LAYOUT_5POINT1|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
237#define AV_CH_LAYOUT_7POINT1_WIDE_BACK (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
238#define AV_CH_LAYOUT_5POINT1POINT2_BACK (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT)
239#define AV_CH_LAYOUT_OCTAGONAL (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_LEFT|AV_CH_BACK_CENTER|AV_CH_BACK_RIGHT)
240#define AV_CH_LAYOUT_CUBE (AV_CH_LAYOUT_QUAD|AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT|AV_CH_TOP_BACK_LEFT|AV_CH_TOP_BACK_RIGHT)
241#define AV_CH_LAYOUT_5POINT1POINT4_BACK (AV_CH_LAYOUT_5POINT1POINT2_BACK|AV_CH_TOP_BACK_LEFT|AV_CH_TOP_BACK_RIGHT)
242#define AV_CH_LAYOUT_7POINT1POINT2 (AV_CH_LAYOUT_7POINT1|AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT)
243#define AV_CH_LAYOUT_7POINT1POINT4_BACK (AV_CH_LAYOUT_7POINT1POINT2|AV_CH_TOP_BACK_LEFT|AV_CH_TOP_BACK_RIGHT)
244#define AV_CH_LAYOUT_7POINT2POINT3 (AV_CH_LAYOUT_7POINT1POINT2|AV_CH_TOP_BACK_CENTER|AV_CH_LOW_FREQUENCY_2)
245#define AV_CH_LAYOUT_9POINT1POINT4_BACK (AV_CH_LAYOUT_7POINT1POINT4_BACK|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
246#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)
247#define AV_CH_LAYOUT_STEREO_DOWNMIX (AV_CH_STEREO_LEFT|AV_CH_STEREO_RIGHT)
248#define AV_CH_LAYOUT_22POINT2 (AV_CH_LAYOUT_7POINT1POINT4_BACK|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER|AV_CH_BACK_CENTER|AV_CH_LOW_FREQUENCY_2|AV_CH_TOP_FRONT_CENTER|AV_CH_TOP_CENTER|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)
249
250#define AV_CH_LAYOUT_7POINT1_TOP_BACK AV_CH_LAYOUT_5POINT1POINT2_BACK
251
262
263/**
264 * @}
265 */
266
267/**
268 * An AVChannelCustom defines a single channel within a custom order layout
269 *
270 * Unlike most structures in FFmpeg, sizeof(AVChannelCustom) is a part of the
271 * public ABI.
272 *
273 * No new fields may be added to it without a major version bump.
274 */
275typedef struct AVChannelCustom {
277 char name[16];
278 void *opaque;
280
281/**
282 * An AVChannelLayout holds information about the channel layout of audio data.
283 *
284 * A channel layout here is defined as a set of channels ordered in a specific
285 * way (unless the channel order is AV_CHANNEL_ORDER_UNSPEC, in which case an
286 * AVChannelLayout carries only the channel count).
287 * All orders may be treated as if they were AV_CHANNEL_ORDER_UNSPEC by
288 * ignoring everything but the channel count, as long as av_channel_layout_check()
289 * considers they are valid.
290 *
291 * Unlike most structures in FFmpeg, sizeof(AVChannelLayout) is a part of the
292 * public ABI and may be used by the caller. E.g. it may be allocated on stack
293 * or embedded in caller-defined structs.
294 *
295 * AVChannelLayout can be initialized as follows:
296 * - default initialization with {0}, followed by setting all used fields
297 * correctly;
298 * - by assigning one of the predefined AV_CHANNEL_LAYOUT_* initializers;
299 * - with a constructor function, such as av_channel_layout_default(),
300 * av_channel_layout_from_mask() or av_channel_layout_from_string().
301 *
302 * The channel layout must be unitialized with av_channel_layout_uninit()
303 *
304 * Copying an AVChannelLayout via assigning is forbidden,
305 * av_channel_layout_copy() must be used instead (and its return value should
306 * be checked)
307 *
308 * No new fields may be added to it without a major version bump, except for
309 * new elements of the union fitting in sizeof(uint64_t).
310 */
311typedef struct AVChannelLayout {
312 /**
313 * Channel order used in this layout.
314 * This is a mandatory field.
315 */
317
318 /**
319 * Number of channels in this layout. Mandatory field.
320 */
322
323 /**
324 * Details about which channels are present in this layout.
325 * For AV_CHANNEL_ORDER_UNSPEC, this field is undefined and must not be
326 * used.
327 */
328 union {
329 /**
330 * This member must be used for AV_CHANNEL_ORDER_NATIVE, and may be used
331 * for AV_CHANNEL_ORDER_AMBISONIC to signal non-diegetic channels.
332 * It is a bitmask, where the position of each set bit means that the
333 * AVChannel with the corresponding value is present.
334 *
335 * I.e. when (mask & (1 << AV_CHAN_FOO)) is non-zero, then AV_CHAN_FOO
336 * is present in the layout. Otherwise it is not present.
337 *
338 * @note when a channel layout using a bitmask is constructed or
339 * modified manually (i.e. not using any of the av_channel_layout_*
340 * functions), the code doing it must ensure that the number of set bits
341 * is equal to nb_channels.
342 */
343 uint64_t mask;
344 /**
345 * This member must be used when the channel order is
346 * AV_CHANNEL_ORDER_CUSTOM. It is a nb_channels-sized array, with each
347 * element signalling the presence of the AVChannel with the
348 * corresponding value in map[i].id.
349 *
350 * I.e. when map[i].id is equal to AV_CHAN_FOO, then AV_CH_FOO is the
351 * i-th channel in the audio data.
352 *
353 * When map[i].id is in the range between AV_CHAN_AMBISONIC_BASE and
354 * AV_CHAN_AMBISONIC_END (inclusive), the channel contains an ambisonic
355 * component with ACN index (as defined above)
356 * n = map[i].id - AV_CHAN_AMBISONIC_BASE.
357 *
358 * map[i].name may be filled with a 0-terminated string, in which case
359 * it will be used for the purpose of identifying the channel with the
360 * convenience functions below. Otherise it must be zeroed.
361 */
363 } u;
364
365 /**
366 * For some private data of the user.
367 */
368 void *opaque;
370
371/**
372 * Macro to define native channel layouts
373 *
374 * @note This doesn't use designated initializers for compatibility with C++ 17 and older.
375 */
376#define AV_CHANNEL_LAYOUT_MASK(nb, m) \
377 { /* .order */ AV_CHANNEL_ORDER_NATIVE, \
378 /* .nb_channels */ (nb), \
379 /* .u.mask */ { m }, \
380 /* .opaque */ NULL }
381
382/**
383 * @name Common pre-defined channel layouts
384 * @{
385 */
386#define AV_CHANNEL_LAYOUT_MONO AV_CHANNEL_LAYOUT_MASK(1, AV_CH_LAYOUT_MONO)
387#define AV_CHANNEL_LAYOUT_STEREO AV_CHANNEL_LAYOUT_MASK(2, AV_CH_LAYOUT_STEREO)
388#define AV_CHANNEL_LAYOUT_2POINT1 AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_2POINT1)
389#define AV_CHANNEL_LAYOUT_2_1 AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_2_1)
390#define AV_CHANNEL_LAYOUT_SURROUND AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_SURROUND)
391#define AV_CHANNEL_LAYOUT_3POINT1 AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_3POINT1)
392#define AV_CHANNEL_LAYOUT_4POINT0 AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_4POINT0)
393#define AV_CHANNEL_LAYOUT_4POINT1 AV_CHANNEL_LAYOUT_MASK(5, AV_CH_LAYOUT_4POINT1)
394#define AV_CHANNEL_LAYOUT_2_2 AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_2_2)
395#define AV_CHANNEL_LAYOUT_QUAD AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_QUAD)
396#define AV_CHANNEL_LAYOUT_5POINT0 AV_CHANNEL_LAYOUT_MASK(5, AV_CH_LAYOUT_5POINT0)
397#define AV_CHANNEL_LAYOUT_5POINT1 AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_5POINT1)
398#define AV_CHANNEL_LAYOUT_5POINT0_BACK AV_CHANNEL_LAYOUT_MASK(5, AV_CH_LAYOUT_5POINT0_BACK)
399#define AV_CHANNEL_LAYOUT_5POINT1_BACK AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_5POINT1_BACK)
400#define AV_CHANNEL_LAYOUT_6POINT0 AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_6POINT0)
401#define AV_CHANNEL_LAYOUT_6POINT0_FRONT AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_6POINT0_FRONT)
402#define AV_CHANNEL_LAYOUT_3POINT1POINT2 AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_3POINT1POINT2)
403#define AV_CHANNEL_LAYOUT_HEXAGONAL AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_HEXAGONAL)
404#define AV_CHANNEL_LAYOUT_6POINT1 AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_6POINT1)
405#define AV_CHANNEL_LAYOUT_6POINT1_BACK AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_6POINT1_BACK)
406#define AV_CHANNEL_LAYOUT_6POINT1_FRONT AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_6POINT1_FRONT)
407#define AV_CHANNEL_LAYOUT_7POINT0 AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_7POINT0)
408#define AV_CHANNEL_LAYOUT_7POINT0_FRONT AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_7POINT0_FRONT)
409#define AV_CHANNEL_LAYOUT_7POINT1 AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_7POINT1)
410#define AV_CHANNEL_LAYOUT_7POINT1_WIDE AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_7POINT1_WIDE)
411#define AV_CHANNEL_LAYOUT_7POINT1_WIDE_BACK AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_7POINT1_WIDE_BACK)
412#define AV_CHANNEL_LAYOUT_5POINT1POINT2_BACK AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_5POINT1POINT2_BACK)
413#define AV_CHANNEL_LAYOUT_OCTAGONAL AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_OCTAGONAL)
414#define AV_CHANNEL_LAYOUT_CUBE AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_CUBE)
415#define AV_CHANNEL_LAYOUT_5POINT1POINT4_BACK AV_CHANNEL_LAYOUT_MASK(10, AV_CH_LAYOUT_5POINT1POINT4_BACK)
416#define AV_CHANNEL_LAYOUT_7POINT1POINT2 AV_CHANNEL_LAYOUT_MASK(10, AV_CH_LAYOUT_7POINT1POINT2)
417#define AV_CHANNEL_LAYOUT_7POINT1POINT4_BACK AV_CHANNEL_LAYOUT_MASK(12, AV_CH_LAYOUT_7POINT1POINT4_BACK)
418#define AV_CHANNEL_LAYOUT_7POINT2POINT3 AV_CHANNEL_LAYOUT_MASK(12, AV_CH_LAYOUT_7POINT2POINT3)
419#define AV_CHANNEL_LAYOUT_9POINT1POINT4_BACK AV_CHANNEL_LAYOUT_MASK(14, AV_CH_LAYOUT_9POINT1POINT4_BACK)
420#define AV_CHANNEL_LAYOUT_HEXADECAGONAL AV_CHANNEL_LAYOUT_MASK(16, AV_CH_LAYOUT_HEXADECAGONAL)
421#define AV_CHANNEL_LAYOUT_STEREO_DOWNMIX AV_CHANNEL_LAYOUT_MASK(2, AV_CH_LAYOUT_STEREO_DOWNMIX)
422#define AV_CHANNEL_LAYOUT_22POINT2 AV_CHANNEL_LAYOUT_MASK(24, AV_CH_LAYOUT_22POINT2)
423
424#define AV_CHANNEL_LAYOUT_7POINT1_TOP_BACK AV_CHANNEL_LAYOUT_5POINT1POINT2_BACK
425
426#define AV_CHANNEL_LAYOUT_AMBISONIC_FIRST_ORDER \
427 { /* .order */ AV_CHANNEL_ORDER_AMBISONIC, \
428 /* .nb_channels */ 4, \
429 /* .u.mask */ { 0 }, \
430 /* .opaque */ NULL }
431/** @} */
432
433struct AVBPrint;
434
435/**
436 * Get a human readable string in an abbreviated form describing a given channel.
437 * This is the inverse function of @ref av_channel_from_string().
438 *
439 * @param buf pre-allocated buffer where to put the generated string
440 * @param buf_size size in bytes of the buffer.
441 * @param channel the AVChannel whose name to get
442 * @return amount of bytes needed to hold the output string, or a negative AVERROR
443 * on failure. If the returned value is bigger than buf_size, then the
444 * string was truncated.
445 */
446int av_channel_name(char *buf, size_t buf_size, enum AVChannel channel);
447
448/**
449 * bprint variant of av_channel_name().
450 *
451 * @note the string will be appended to the bprint buffer.
452 */
453void av_channel_name_bprint(struct AVBPrint *bp, enum AVChannel channel_id);
454
455/**
456 * Get a human readable string describing a given channel.
457 *
458 * @param buf pre-allocated buffer where to put the generated string
459 * @param buf_size size in bytes of the buffer.
460 * @param channel the AVChannel whose description to get
461 * @return amount of bytes needed to hold the output string, or a negative AVERROR
462 * on failure. If the returned value is bigger than buf_size, then the
463 * string was truncated.
464 */
465int av_channel_description(char *buf, size_t buf_size, enum AVChannel channel);
466
467/**
468 * bprint variant of av_channel_description().
469 *
470 * @note the string will be appended to the bprint buffer.
471 */
472void av_channel_description_bprint(struct AVBPrint *bp, enum AVChannel channel_id);
473
474/**
475 * This is the inverse function of @ref av_channel_name().
476 *
477 * @return the channel with the given name
478 * AV_CHAN_NONE when name does not identify a known channel
479 */
480enum AVChannel av_channel_from_string(const char *name);
481
482/**
483 * Initialize a custom channel layout with the specified number of channels.
484 * The channel map will be allocated and the designation of all channels will
485 * be set to AV_CHAN_UNKNOWN.
486 *
487 * This is only a convenience helper function, a custom channel layout can also
488 * be constructed without using this.
489 *
490 * @param channel_layout the layout structure to be initialized
491 * @param nb_channels the number of channels
492 *
493 * @return 0 on success
494 * AVERROR(EINVAL) if the number of channels <= 0
495 * AVERROR(ENOMEM) if the channel map could not be allocated
496 */
497int av_channel_layout_custom_init(AVChannelLayout *channel_layout, int nb_channels);
498
499/**
500 * Initialize a native channel layout from a bitmask indicating which channels
501 * are present.
502 *
503 * @param channel_layout the layout structure to be initialized
504 * @param mask bitmask describing the channel layout
505 *
506 * @return 0 on success
507 * AVERROR(EINVAL) for invalid mask values
508 */
509int av_channel_layout_from_mask(AVChannelLayout *channel_layout, uint64_t mask);
510
511/**
512 * Initialize a channel layout from a given string description.
513 * The input string can be represented by:
514 * - the formal channel layout name (returned by av_channel_layout_describe())
515 * - single or multiple channel names (returned by av_channel_name(), eg. "FL",
516 * or concatenated with "+", each optionally containing a custom name after
517 * a "@", eg. "FL@Left+FR@Right+LFE")
518 * - a decimal or hexadecimal value of a native channel layout (eg. "4" or "0x4")
519 * - the number of channels with default layout (eg. "4c")
520 * - the number of unordered channels (eg. "4C" or "4 channels")
521 * - the ambisonic order followed by optional non-diegetic channels (eg.
522 * "ambisonic 2+stereo")
523 * On error, the channel layout will remain uninitialized, but not necessarily
524 * untouched.
525 *
526 * @param channel_layout uninitialized channel layout for the result
527 * @param str string describing the channel layout
528 * @return 0 on success parsing the channel layout
529 * AVERROR(EINVAL) if an invalid channel layout string was provided
530 * AVERROR(ENOMEM) if there was not enough memory
531 */
533 const char *str);
534
535/**
536 * Get the default channel layout for a given number of channels.
537 *
538 * @param ch_layout the layout structure to be initialized
539 * @param nb_channels number of channels
540 */
541void av_channel_layout_default(AVChannelLayout *ch_layout, int nb_channels);
542
543/**
544 * Iterate over all standard channel layouts.
545 *
546 * @param opaque a pointer where libavutil will store the iteration state. Must
547 * point to NULL to start the iteration.
548 *
549 * @return the standard channel layout or NULL when the iteration is
550 * finished
551 */
553
554/**
555 * Free any allocated data in the channel layout and reset the channel
556 * count to 0.
557 *
558 * @param channel_layout the layout structure to be uninitialized
559 */
561
562/**
563 * Make a copy of a channel layout. This differs from just assigning src to dst
564 * in that it allocates and copies the map for AV_CHANNEL_ORDER_CUSTOM.
565 *
566 * @note the destination channel_layout will be always uninitialized before copy.
567 *
568 * @param dst destination channel layout
569 * @param src source channel layout
570 * @return 0 on success, a negative AVERROR on error.
571 */
573
574/**
575 * Get a human-readable string describing the channel layout properties.
576 * The string will be in the same format that is accepted by
577 * @ref av_channel_layout_from_string(), allowing to rebuild the same
578 * channel layout, except for opaque pointers.
579 *
580 * @param channel_layout channel layout to be described
581 * @param buf pre-allocated buffer where to put the generated string
582 * @param buf_size size in bytes of the buffer.
583 * @return amount of bytes needed to hold the output string, or a negative AVERROR
584 * on failure. If the returned value is bigger than buf_size, then the
585 * string was truncated.
586 */
588 char *buf, size_t buf_size);
589
590/**
591 * bprint variant of av_channel_layout_describe().
592 *
593 * @note the string will be appended to the bprint buffer.
594 * @return 0 on success, or a negative AVERROR value on failure.
595 */
597 struct AVBPrint *bp);
598
599/**
600 * Get the channel with the given index in a channel layout.
601 *
602 * @param channel_layout input channel layout
603 * @param idx index of the channel
604 * @return channel with the index idx in channel_layout on success or
605 * AV_CHAN_NONE on failure (if idx is not valid or the channel order is
606 * unspecified)
607 */
608enum AVChannel
609av_channel_layout_channel_from_index(const AVChannelLayout *channel_layout, unsigned int idx);
610
611/**
612 * Get the index of a given channel in a channel layout. In case multiple
613 * channels are found, only the first match will be returned.
614 *
615 * @param channel_layout input channel layout
616 * @param channel the channel whose index to obtain
617 * @return index of channel in channel_layout on success or a negative number if
618 * channel is not present in channel_layout.
619 */
621 enum AVChannel channel);
622
623/**
624 * Get the index in a channel layout of a channel described by the given string.
625 * In case multiple channels are found, only the first match will be returned.
626 *
627 * This function accepts channel names in the same format as
628 * @ref av_channel_from_string().
629 *
630 * @param channel_layout input channel layout
631 * @param name string describing the channel whose index to obtain
632 * @return a channel index described by the given string, or a negative AVERROR
633 * value.
634 */
636 const char *name);
637
638/**
639 * Get a channel described by the given string.
640 *
641 * This function accepts channel names in the same format as
642 * @ref av_channel_from_string().
643 *
644 * @param channel_layout input channel layout
645 * @param name string describing the channel to obtain
646 * @return a channel described by the given string in channel_layout on success
647 * or AV_CHAN_NONE on failure (if the string is not valid or the channel
648 * order is unspecified)
649 */
650enum AVChannel
652 const char *name);
653
654/**
655 * Find out what channels from a given set are present in a channel layout,
656 * without regard for their positions.
657 *
658 * @param channel_layout input channel layout
659 * @param mask a combination of AV_CH_* representing a set of channels
660 * @return a bitfield representing all the channels from mask that are present
661 * in channel_layout
662 */
663uint64_t av_channel_layout_subset(const AVChannelLayout *channel_layout,
664 uint64_t mask);
665
666/**
667 * Check whether a channel layout is valid, i.e. can possibly describe audio
668 * data.
669 *
670 * @param channel_layout input channel layout
671 * @return 1 if channel_layout is valid, 0 otherwise.
672 */
673int av_channel_layout_check(const AVChannelLayout *channel_layout);
674
675/**
676 * Check whether two channel layouts are semantically the same, i.e. the same
677 * channels are present on the same positions in both.
678 *
679 * If one of the channel layouts is AV_CHANNEL_ORDER_UNSPEC, while the other is
680 * not, they are considered to be unequal. If both are AV_CHANNEL_ORDER_UNSPEC,
681 * they are considered equal iff the channel counts are the same in both.
682 *
683 * @param chl input channel layout
684 * @param chl1 input channel layout
685 * @return 0 if chl and chl1 are equal, 1 if they are not equal. A negative
686 * AVERROR code if one or both are invalid.
687 */
689
690/**
691 * Return the order if the layout is n-th order standard-order ambisonic.
692 * The presence of optional extra non-diegetic channels at the end is not taken
693 * into account.
694 *
695 * @param channel_layout input channel layout
696 * @return the order of the layout, a negative error code otherwise.
697 */
699
700/**
701 * The conversion must be lossless.
702 */
703#define AV_CHANNEL_LAYOUT_RETYPE_FLAG_LOSSLESS (1 << 0)
704
705/**
706 * The specified retype target order is ignored and the simplest possible
707 * (canonical) order is used for which the input layout can be losslessy
708 * represented.
709 */
710#define AV_CHANNEL_LAYOUT_RETYPE_FLAG_CANONICAL (1 << 1)
711
712/**
713 * Change the AVChannelOrder of a channel layout.
714 *
715 * Change of AVChannelOrder can be either lossless or lossy. In case of a
716 * lossless conversion all the channel designations and the associated channel
717 * names (if any) are kept. On a lossy conversion the channel names and channel
718 * designations might be lost depending on the capabilities of the desired
719 * AVChannelOrder. Note that some conversions are simply not possible in which
720 * case this function returns AVERROR(ENOSYS).
721 *
722 * The following conversions are supported:
723 *
724 * Any -> Custom : Always possible, always lossless.
725 * Any -> Unspecified: Always possible, lossless if channel designations
726 * are all unknown and channel names are not used, lossy otherwise.
727 * Custom -> Ambisonic : Possible if it contains ambisonic channels with
728 * optional non-diegetic channels in the end. Lossy if the channels have
729 * custom names, lossless otherwise.
730 * Custom -> Native : Possible if it contains native channels in native
731 * order. Lossy if the channels have custom names, lossless otherwise.
732 *
733 * On error this function keeps the original channel layout untouched.
734 *
735 * @param channel_layout channel layout which will be changed
736 * @param order the desired channel layout order
737 * @param flags a combination of AV_CHANNEL_LAYOUT_RETYPE_FLAG_* constants
738 * @return 0 if the conversion was successful and lossless or if the channel
739 * layout was already in the desired order
740 * >0 if the conversion was successful but lossy
741 * AVERROR(ENOSYS) if the conversion was not possible (or would be
742 * lossy and AV_CHANNEL_LAYOUT_RETYPE_FLAG_LOSSLESS was specified)
743 * AVERROR(EINVAL), AVERROR(ENOMEM) on error
744 */
745int av_channel_layout_retype(AVChannelLayout *channel_layout, enum AVChannelOrder order, int flags);
746
747/**
748 * @}
749 */
750
751#endif /* AVUTIL_CHANNEL_LAYOUT_H */
Macro definitions for various function/variable attributes.
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.
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.
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.
int av_channel_layout_retype(AVChannelLayout *channel_layout, enum AVChannelOrder order, int flags)
Change the AVChannelOrder 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_ambisonic_order(const AVChannelLayout *channel_layout)
Return the order if the layout is n-th order standard-order ambisonic.
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.
int av_channel_layout_custom_init(AVChannelLayout *channel_layout, int nb_channels)
Initialize a custom channel layout with the specified number of channels.
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.
void av_channel_layout_uninit(AVChannelLayout *channel_layout)
Free any allocated data in the channel layout and reset the channel count to 0.
AVChannel
void av_channel_name_bprint(struct AVBPrint *bp, enum AVChannel channel_id)
bprint variant of av_channel_name().
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.
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.
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...
const AVChannelLayout * av_channel_layout_standard(void **opaque)
Iterate over all standard channel layouts.
enum AVChannel av_channel_from_string(const char *name)
This is the inverse function of av_channel_name().
@ AV_CHANNEL_ORDER_NATIVE
The native channel order, i.e.
@ FF_CHANNEL_ORDER_NB
Number of channel orders, not part of ABI/API.
@ 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_TOP_SURROUND_RIGHT
-110 degrees, Rvs, TpRS
@ AV_CHAN_FRONT_RIGHT_OF_CENTER
@ AV_CHAN_FRONT_LEFT
@ AV_CHAN_SIDE_SURROUND_RIGHT
-90 degrees, Rss, SiR
@ 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_TOP_SURROUND_LEFT
+110 degrees, Lvs, TpLS
@ AV_CHAN_SIDE_RIGHT
@ AV_CHAN_SIDE_SURROUND_LEFT
+90 degrees, Lss, SiL
@ 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
swscale version macros
Buffer to print data progressively.
Definition bprint.h:99
char * str
string so far
Definition bprint.h:99
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.
union AVChannelLayout::@6 u
Details about which channels are present 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 ...
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.