FFmpeg
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 
47 enum AVChannel {
48  ///< Invalid channel index
68  /** Stereo downmix. */
70  /** See above. */
82 
83  /** Channel is empty can be safely skipped. */
84  AV_CHAN_UNUSED = 0x200,
85 
86  /** Channel contains data, but its position is unknown. */
87  AV_CHAN_UNKNOWN = 0x300,
88 
89  /**
90  * Range of channels between AV_CHAN_AMBISONIC_BASE and
91  * AV_CHAN_AMBISONIC_END represent Ambisonic components using the ACN system.
92  *
93  * Given a channel id `<i>` between AV_CHAN_AMBISONIC_BASE and
94  * AV_CHAN_AMBISONIC_END (inclusive), the ACN index of the channel `<n>` is
95  * `<n> = <i> - AV_CHAN_AMBISONIC_BASE`.
96  *
97  * @note these values are only used for AV_CHANNEL_ORDER_CUSTOM channel
98  * orderings, the AV_CHANNEL_ORDER_AMBISONIC ordering orders the channels
99  * implicitly by their position in the stream.
100  */
102  // leave space for 1024 ids, which correspond to maximum order-32 harmonics,
103  // which should be enough for the foreseeable use cases
105 };
106 
108  /**
109  * Only the channel count is specified, without any further information
110  * about the channel order.
111  */
113  /**
114  * The native channel order, i.e. the channels are in the same order in
115  * which they are defined in the AVChannel enum. This supports up to 63
116  * different channels.
117  */
119  /**
120  * The channel order does not correspond to any other predefined order and
121  * is stored as an explicit map. For example, this could be used to support
122  * layouts with 64 or more channels, or with empty/skipped (AV_CHAN_SILENCE)
123  * channels at arbitrary positions.
124  */
126  /**
127  * The audio is represented as the decomposition of the sound field into
128  * spherical harmonics. Each channel corresponds to a single expansion
129  * component. Channels are ordered according to ACN (Ambisonic Channel
130  * Number).
131  *
132  * The channel with the index n in the stream contains the spherical
133  * harmonic of degree l and order m given by
134  * @code{.unparsed}
135  * l = floor(sqrt(n)),
136  * m = n - l * (l + 1).
137  * @endcode
138  *
139  * Conversely given a spherical harmonic of degree l and order m, the
140  * corresponding channel index n is given by
141  * @code{.unparsed}
142  * n = l * (l + 1) + m.
143  * @endcode
144  *
145  * Normalization is assumed to be SN3D (Schmidt Semi-Normalization)
146  * as defined in AmbiX format $ 2.1.
147  */
149 };
150 
151 
152 /**
153  * @defgroup channel_masks Audio channel masks
154  *
155  * A channel layout is a 64-bits integer with a bit set for every channel.
156  * The number of bits set must be equal to the number of channels.
157  * The value 0 means that the channel layout is not known.
158  * @note this data structure is not powerful enough to handle channels
159  * combinations that have the same channel multiple times, such as
160  * dual-mono.
161  *
162  * @{
163  */
164 #define AV_CH_FRONT_LEFT (1ULL << AV_CHAN_FRONT_LEFT )
165 #define AV_CH_FRONT_RIGHT (1ULL << AV_CHAN_FRONT_RIGHT )
166 #define AV_CH_FRONT_CENTER (1ULL << AV_CHAN_FRONT_CENTER )
167 #define AV_CH_LOW_FREQUENCY (1ULL << AV_CHAN_LOW_FREQUENCY )
168 #define AV_CH_BACK_LEFT (1ULL << AV_CHAN_BACK_LEFT )
169 #define AV_CH_BACK_RIGHT (1ULL << AV_CHAN_BACK_RIGHT )
170 #define AV_CH_FRONT_LEFT_OF_CENTER (1ULL << AV_CHAN_FRONT_LEFT_OF_CENTER )
171 #define AV_CH_FRONT_RIGHT_OF_CENTER (1ULL << AV_CHAN_FRONT_RIGHT_OF_CENTER)
172 #define AV_CH_BACK_CENTER (1ULL << AV_CHAN_BACK_CENTER )
173 #define AV_CH_SIDE_LEFT (1ULL << AV_CHAN_SIDE_LEFT )
174 #define AV_CH_SIDE_RIGHT (1ULL << AV_CHAN_SIDE_RIGHT )
175 #define AV_CH_TOP_CENTER (1ULL << AV_CHAN_TOP_CENTER )
176 #define AV_CH_TOP_FRONT_LEFT (1ULL << AV_CHAN_TOP_FRONT_LEFT )
177 #define AV_CH_TOP_FRONT_CENTER (1ULL << AV_CHAN_TOP_FRONT_CENTER )
178 #define AV_CH_TOP_FRONT_RIGHT (1ULL << AV_CHAN_TOP_FRONT_RIGHT )
179 #define AV_CH_TOP_BACK_LEFT (1ULL << AV_CHAN_TOP_BACK_LEFT )
180 #define AV_CH_TOP_BACK_CENTER (1ULL << AV_CHAN_TOP_BACK_CENTER )
181 #define AV_CH_TOP_BACK_RIGHT (1ULL << AV_CHAN_TOP_BACK_RIGHT )
182 #define AV_CH_STEREO_LEFT (1ULL << AV_CHAN_STEREO_LEFT )
183 #define AV_CH_STEREO_RIGHT (1ULL << AV_CHAN_STEREO_RIGHT )
184 #define AV_CH_WIDE_LEFT (1ULL << AV_CHAN_WIDE_LEFT )
185 #define AV_CH_WIDE_RIGHT (1ULL << AV_CHAN_WIDE_RIGHT )
186 #define AV_CH_SURROUND_DIRECT_LEFT (1ULL << AV_CHAN_SURROUND_DIRECT_LEFT )
187 #define AV_CH_SURROUND_DIRECT_RIGHT (1ULL << AV_CHAN_SURROUND_DIRECT_RIGHT)
188 #define AV_CH_LOW_FREQUENCY_2 (1ULL << AV_CHAN_LOW_FREQUENCY_2 )
189 #define AV_CH_TOP_SIDE_LEFT (1ULL << AV_CHAN_TOP_SIDE_LEFT )
190 #define AV_CH_TOP_SIDE_RIGHT (1ULL << AV_CHAN_TOP_SIDE_RIGHT )
191 #define AV_CH_BOTTOM_FRONT_CENTER (1ULL << AV_CHAN_BOTTOM_FRONT_CENTER )
192 #define AV_CH_BOTTOM_FRONT_LEFT (1ULL << AV_CHAN_BOTTOM_FRONT_LEFT )
193 #define AV_CH_BOTTOM_FRONT_RIGHT (1ULL << AV_CHAN_BOTTOM_FRONT_RIGHT )
194 
195 #if FF_API_OLD_CHANNEL_LAYOUT
196 /** Channel mask value used for AVCodecContext.request_channel_layout
197  to indicate that the user requests the channel order of the decoder output
198  to be the native codec channel order.
199  @deprecated channel order is now indicated in a special field in
200  AVChannelLayout
201  */
202 #define AV_CH_LAYOUT_NATIVE 0x8000000000000000ULL
203 #endif
204 
205 /**
206  * @}
207  * @defgroup channel_mask_c Audio channel layouts
208  * @{
209  * */
210 #define AV_CH_LAYOUT_MONO (AV_CH_FRONT_CENTER)
211 #define AV_CH_LAYOUT_STEREO (AV_CH_FRONT_LEFT|AV_CH_FRONT_RIGHT)
212 #define AV_CH_LAYOUT_2POINT1 (AV_CH_LAYOUT_STEREO|AV_CH_LOW_FREQUENCY)
213 #define AV_CH_LAYOUT_2_1 (AV_CH_LAYOUT_STEREO|AV_CH_BACK_CENTER)
214 #define AV_CH_LAYOUT_SURROUND (AV_CH_LAYOUT_STEREO|AV_CH_FRONT_CENTER)
215 #define AV_CH_LAYOUT_3POINT1 (AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY)
216 #define AV_CH_LAYOUT_4POINT0 (AV_CH_LAYOUT_SURROUND|AV_CH_BACK_CENTER)
217 #define AV_CH_LAYOUT_4POINT1 (AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY)
218 #define AV_CH_LAYOUT_2_2 (AV_CH_LAYOUT_STEREO|AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT)
219 #define AV_CH_LAYOUT_QUAD (AV_CH_LAYOUT_STEREO|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
220 #define AV_CH_LAYOUT_5POINT0 (AV_CH_LAYOUT_SURROUND|AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT)
221 #define AV_CH_LAYOUT_5POINT1 (AV_CH_LAYOUT_5POINT0|AV_CH_LOW_FREQUENCY)
222 #define AV_CH_LAYOUT_5POINT0_BACK (AV_CH_LAYOUT_SURROUND|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
223 #define AV_CH_LAYOUT_5POINT1_BACK (AV_CH_LAYOUT_5POINT0_BACK|AV_CH_LOW_FREQUENCY)
224 #define AV_CH_LAYOUT_6POINT0 (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_CENTER)
225 #define AV_CH_LAYOUT_6POINT0_FRONT (AV_CH_LAYOUT_2_2|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
226 #define AV_CH_LAYOUT_HEXAGONAL (AV_CH_LAYOUT_5POINT0_BACK|AV_CH_BACK_CENTER)
227 #define AV_CH_LAYOUT_6POINT1 (AV_CH_LAYOUT_5POINT1|AV_CH_BACK_CENTER)
228 #define AV_CH_LAYOUT_6POINT1_BACK (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_BACK_CENTER)
229 #define AV_CH_LAYOUT_6POINT1_FRONT (AV_CH_LAYOUT_6POINT0_FRONT|AV_CH_LOW_FREQUENCY)
230 #define AV_CH_LAYOUT_7POINT0 (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
231 #define AV_CH_LAYOUT_7POINT0_FRONT (AV_CH_LAYOUT_5POINT0|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
232 #define AV_CH_LAYOUT_7POINT1 (AV_CH_LAYOUT_5POINT1|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
233 #define AV_CH_LAYOUT_7POINT1_WIDE (AV_CH_LAYOUT_5POINT1|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
234 #define AV_CH_LAYOUT_7POINT1_WIDE_BACK (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
235 #define AV_CH_LAYOUT_7POINT1_TOP_BACK (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT)
236 #define AV_CH_LAYOUT_OCTAGONAL (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_LEFT|AV_CH_BACK_CENTER|AV_CH_BACK_RIGHT)
237 #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)
238 #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)
239 #define AV_CH_LAYOUT_STEREO_DOWNMIX (AV_CH_STEREO_LEFT|AV_CH_STEREO_RIGHT)
240 #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)
241 
251 };
252 
253 /**
254  * @}
255  */
256 
257 /**
258  * An AVChannelCustom defines a single channel within a custom order layout
259  *
260  * Unlike most structures in FFmpeg, sizeof(AVChannelCustom) is a part of the
261  * public ABI.
262  *
263  * No new fields may be added to it without a major version bump.
264  */
265 typedef struct AVChannelCustom {
266  enum AVChannel id;
267  char name[16];
268  void *opaque;
270 
271 /**
272  * An AVChannelLayout holds information about the channel layout of audio data.
273  *
274  * A channel layout here is defined as a set of channels ordered in a specific
275  * way (unless the channel order is AV_CHANNEL_ORDER_UNSPEC, in which case an
276  * AVChannelLayout carries only the channel count).
277  * All orders may be treated as if they were AV_CHANNEL_ORDER_UNSPEC by
278  * ignoring everything but the channel count, as long as av_channel_layout_check()
279  * considers they are valid.
280  *
281  * Unlike most structures in FFmpeg, sizeof(AVChannelLayout) is a part of the
282  * public ABI and may be used by the caller. E.g. it may be allocated on stack
283  * or embedded in caller-defined structs.
284  *
285  * AVChannelLayout can be initialized as follows:
286  * - default initialization with {0}, followed by setting all used fields
287  * correctly;
288  * - by assigning one of the predefined AV_CHANNEL_LAYOUT_* initializers;
289  * - with a constructor function, such as av_channel_layout_default(),
290  * av_channel_layout_from_mask() or av_channel_layout_from_string().
291  *
292  * The channel layout must be unitialized with av_channel_layout_uninit()
293  *
294  * Copying an AVChannelLayout via assigning is forbidden,
295  * av_channel_layout_copy() must be used instead (and its return value should
296  * be checked)
297  *
298  * No new fields may be added to it without a major version bump, except for
299  * new elements of the union fitting in sizeof(uint64_t).
300  */
301 typedef struct AVChannelLayout {
302  /**
303  * Channel order used in this layout.
304  * This is a mandatory field.
305  */
306  enum AVChannelOrder order;
307 
308  /**
309  * Number of channels in this layout. Mandatory field.
310  */
312 
313  /**
314  * Details about which channels are present in this layout.
315  * For AV_CHANNEL_ORDER_UNSPEC, this field is undefined and must not be
316  * used.
317  */
318  union {
319  /**
320  * This member must be used for AV_CHANNEL_ORDER_NATIVE, and may be used
321  * for AV_CHANNEL_ORDER_AMBISONIC to signal non-diegetic channels.
322  * It is a bitmask, where the position of each set bit means that the
323  * AVChannel with the corresponding value is present.
324  *
325  * I.e. when (mask & (1 << AV_CHAN_FOO)) is non-zero, then AV_CHAN_FOO
326  * is present in the layout. Otherwise it is not present.
327  *
328  * @note when a channel layout using a bitmask is constructed or
329  * modified manually (i.e. not using any of the av_channel_layout_*
330  * functions), the code doing it must ensure that the number of set bits
331  * is equal to nb_channels.
332  */
333  uint64_t mask;
334  /**
335  * This member must be used when the channel order is
336  * AV_CHANNEL_ORDER_CUSTOM. It is a nb_channels-sized array, with each
337  * element signalling the presence of the AVChannel with the
338  * corresponding value in map[i].id.
339  *
340  * I.e. when map[i].id is equal to AV_CHAN_FOO, then AV_CH_FOO is the
341  * i-th channel in the audio data.
342  *
343  * When map[i].id is in the range between AV_CHAN_AMBISONIC_BASE and
344  * AV_CHAN_AMBISONIC_END (inclusive), the channel contains an ambisonic
345  * component with ACN index (as defined above)
346  * n = map[i].id - AV_CHAN_AMBISONIC_BASE.
347  *
348  * map[i].name may be filled with a 0-terminated string, in which case
349  * it will be used for the purpose of identifying the channel with the
350  * convenience functions below. Otherise it must be zeroed.
351  */
353  } u;
354 
355  /**
356  * For some private data of the user.
357  */
358  void *opaque;
360 
361 #define AV_CHANNEL_LAYOUT_MASK(nb, m) \
362  { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = (nb), .u = { .mask = (m) }}
363 
364 /**
365  * @name Common pre-defined channel layouts
366  * @{
367  */
368 #define AV_CHANNEL_LAYOUT_MONO AV_CHANNEL_LAYOUT_MASK(1, AV_CH_LAYOUT_MONO)
369 #define AV_CHANNEL_LAYOUT_STEREO AV_CHANNEL_LAYOUT_MASK(2, AV_CH_LAYOUT_STEREO)
370 #define AV_CHANNEL_LAYOUT_2POINT1 AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_2POINT1)
371 #define AV_CHANNEL_LAYOUT_2_1 AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_2_1)
372 #define AV_CHANNEL_LAYOUT_SURROUND AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_SURROUND)
373 #define AV_CHANNEL_LAYOUT_3POINT1 AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_3POINT1)
374 #define AV_CHANNEL_LAYOUT_4POINT0 AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_4POINT0)
375 #define AV_CHANNEL_LAYOUT_4POINT1 AV_CHANNEL_LAYOUT_MASK(5, AV_CH_LAYOUT_4POINT1)
376 #define AV_CHANNEL_LAYOUT_2_2 AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_2_2)
377 #define AV_CHANNEL_LAYOUT_QUAD AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_QUAD)
378 #define AV_CHANNEL_LAYOUT_5POINT0 AV_CHANNEL_LAYOUT_MASK(5, AV_CH_LAYOUT_5POINT0)
379 #define AV_CHANNEL_LAYOUT_5POINT1 AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_5POINT1)
380 #define AV_CHANNEL_LAYOUT_5POINT0_BACK AV_CHANNEL_LAYOUT_MASK(5, AV_CH_LAYOUT_5POINT0_BACK)
381 #define AV_CHANNEL_LAYOUT_5POINT1_BACK AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_5POINT1_BACK)
382 #define AV_CHANNEL_LAYOUT_6POINT0 AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_6POINT0)
383 #define AV_CHANNEL_LAYOUT_6POINT0_FRONT AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_6POINT0_FRONT)
384 #define AV_CHANNEL_LAYOUT_HEXAGONAL AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_HEXAGONAL)
385 #define AV_CHANNEL_LAYOUT_6POINT1 AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_6POINT1)
386 #define AV_CHANNEL_LAYOUT_6POINT1_BACK AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_6POINT1_BACK)
387 #define AV_CHANNEL_LAYOUT_6POINT1_FRONT AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_6POINT1_FRONT)
388 #define AV_CHANNEL_LAYOUT_7POINT0 AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_7POINT0)
389 #define AV_CHANNEL_LAYOUT_7POINT0_FRONT AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_7POINT0_FRONT)
390 #define AV_CHANNEL_LAYOUT_7POINT1 AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_7POINT1)
391 #define AV_CHANNEL_LAYOUT_7POINT1_WIDE AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_7POINT1_WIDE)
392 #define AV_CHANNEL_LAYOUT_7POINT1_WIDE_BACK AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_7POINT1_WIDE_BACK)
393 #define AV_CHANNEL_LAYOUT_7POINT1_TOP_BACK AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_7POINT1_TOP_BACK)
394 #define AV_CHANNEL_LAYOUT_OCTAGONAL AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_OCTAGONAL)
395 #define AV_CHANNEL_LAYOUT_CUBE AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_CUBE)
396 #define AV_CHANNEL_LAYOUT_HEXADECAGONAL AV_CHANNEL_LAYOUT_MASK(16, AV_CH_LAYOUT_HEXADECAGONAL)
397 #define AV_CHANNEL_LAYOUT_STEREO_DOWNMIX AV_CHANNEL_LAYOUT_MASK(2, AV_CH_LAYOUT_STEREO_DOWNMIX)
398 #define AV_CHANNEL_LAYOUT_22POINT2 AV_CHANNEL_LAYOUT_MASK(24, AV_CH_LAYOUT_22POINT2)
399 #define AV_CHANNEL_LAYOUT_AMBISONIC_FIRST_ORDER \
400  { .order = AV_CHANNEL_ORDER_AMBISONIC, .nb_channels = 4, .u = { .mask = 0 }}
401 /** @} */
402 
403 struct AVBPrint;
404 
405 #if FF_API_OLD_CHANNEL_LAYOUT
406 /**
407  * @name Deprecated Functions
408  * @{
409  */
410 
411 /**
412  * Return a channel layout id that matches name, or 0 if no match is found.
413  *
414  * name can be one or several of the following notations,
415  * separated by '+' or '|':
416  * - the name of an usual channel layout (mono, stereo, 4.0, quad, 5.0,
417  * 5.0(side), 5.1, 5.1(side), 7.1, 7.1(wide), downmix);
418  * - the name of a single channel (FL, FR, FC, LFE, BL, BR, FLC, FRC, BC,
419  * SL, SR, TC, TFL, TFC, TFR, TBL, TBC, TBR, DL, DR);
420  * - a number of channels, in decimal, followed by 'c', yielding
421  * the default channel layout for that number of channels (@see
422  * av_get_default_channel_layout);
423  * - a channel layout mask, in hexadecimal starting with "0x" (see the
424  * AV_CH_* macros).
425  *
426  * Example: "stereo+FC" = "2c+FC" = "2c+1c" = "0x7"
427  *
428  * @deprecated use av_channel_layout_from_string()
429  */
431 uint64_t av_get_channel_layout(const char *name);
432 
433 /**
434  * Return a channel layout and the number of channels based on the specified name.
435  *
436  * This function is similar to (@see av_get_channel_layout), but can also parse
437  * unknown channel layout specifications.
438  *
439  * @param[in] name channel layout specification string
440  * @param[out] channel_layout parsed channel layout (0 if unknown)
441  * @param[out] nb_channels number of channels
442  *
443  * @return 0 on success, AVERROR(EINVAL) if the parsing fails.
444  * @deprecated use av_channel_layout_from_string()
445  */
447 int av_get_extended_channel_layout(const char *name, uint64_t* channel_layout, int* nb_channels);
448 
449 /**
450  * Return a description of a channel layout.
451  * If nb_channels is <= 0, it is guessed from the channel_layout.
452  *
453  * @param buf put here the string containing the channel layout
454  * @param buf_size size in bytes of the buffer
455  * @param nb_channels number of channels
456  * @param channel_layout channel layout bitset
457  * @deprecated use av_channel_layout_describe()
458  */
460 void av_get_channel_layout_string(char *buf, int buf_size, int nb_channels, uint64_t channel_layout);
461 
462 /**
463  * Append a description of a channel layout to a bprint buffer.
464  * @deprecated use av_channel_layout_describe()
465  */
467 void av_bprint_channel_layout(struct AVBPrint *bp, int nb_channels, uint64_t channel_layout);
468 
469 /**
470  * Return the number of channels in the channel layout.
471  * @deprecated use AVChannelLayout.nb_channels
472  */
474 int av_get_channel_layout_nb_channels(uint64_t channel_layout);
475 
476 /**
477  * Return default channel layout for a given number of channels.
478  *
479  * @deprecated use av_channel_layout_default()
480  */
482 int64_t av_get_default_channel_layout(int nb_channels);
483 
484 /**
485  * Get the index of a channel in channel_layout.
486  *
487  * @param channel_layout channel layout bitset
488  * @param channel a channel layout describing exactly one channel which must be
489  * present in channel_layout.
490  *
491  * @return index of channel in channel_layout on success, a negative AVERROR
492  * on error.
493  *
494  * @deprecated use av_channel_layout_index_from_channel()
495  */
497 int av_get_channel_layout_channel_index(uint64_t channel_layout,
498  uint64_t channel);
499 
500 /**
501  * Get the channel with the given index in channel_layout.
502  * @deprecated use av_channel_layout_channel_from_index()
503  */
505 uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index);
506 
507 /**
508  * Get the name of a given channel.
509  *
510  * @return channel name on success, NULL on error.
511  *
512  * @deprecated use av_channel_name()
513  */
515 const char *av_get_channel_name(uint64_t channel);
516 
517 /**
518  * Get the description of a given channel.
519  *
520  * @param channel a channel layout with a single channel
521  * @return channel description on success, NULL on error
522  * @deprecated use av_channel_description()
523  */
525 const char *av_get_channel_description(uint64_t channel);
526 
527 /**
528  * Get the value and name of a standard channel layout.
529  *
530  * @param[in] index index in an internal list, starting at 0
531  * @param[out] layout channel layout mask
532  * @param[out] name name of the layout
533  * @return 0 if the layout exists,
534  * <0 if index is beyond the limits
535  * @deprecated use av_channel_layout_standard()
536  */
538 int av_get_standard_channel_layout(unsigned index, uint64_t *layout,
539  const char **name);
540 /**
541  * @}
542  */
543 #endif
544 
545 /**
546  * Get a human readable string in an abbreviated form describing a given channel.
547  * This is the inverse function of @ref av_channel_from_string().
548  *
549  * @param buf pre-allocated buffer where to put the generated string
550  * @param buf_size size in bytes of the buffer.
551  * @param channel the AVChannel whose name to get
552  * @return amount of bytes needed to hold the output string, or a negative AVERROR
553  * on failure. If the returned value is bigger than buf_size, then the
554  * string was truncated.
555  */
556 int av_channel_name(char *buf, size_t buf_size, enum AVChannel channel);
557 
558 /**
559  * bprint variant of av_channel_name().
560  *
561  * @note the string will be appended to the bprint buffer.
562  */
563 void av_channel_name_bprint(struct AVBPrint *bp, enum AVChannel channel_id);
564 
565 /**
566  * Get a human readable string describing a given channel.
567  *
568  * @param buf pre-allocated buffer where to put the generated string
569  * @param buf_size size in bytes of the buffer.
570  * @param channel the AVChannel whose description to get
571  * @return amount of bytes needed to hold the output string, or a negative AVERROR
572  * on failure. If the returned value is bigger than buf_size, then the
573  * string was truncated.
574  */
575 int av_channel_description(char *buf, size_t buf_size, enum AVChannel channel);
576 
577 /**
578  * bprint variant of av_channel_description().
579  *
580  * @note the string will be appended to the bprint buffer.
581  */
582 void av_channel_description_bprint(struct AVBPrint *bp, enum AVChannel channel_id);
583 
584 /**
585  * This is the inverse function of @ref av_channel_name().
586  *
587  * @return the channel with the given name
588  * AV_CHAN_NONE when name does not identify a known channel
589  */
590 enum AVChannel av_channel_from_string(const char *name);
591 
592 /**
593  * Initialize a native channel layout from a bitmask indicating which channels
594  * are present.
595  *
596  * @param channel_layout the layout structure to be initialized
597  * @param mask bitmask describing the channel layout
598  *
599  * @return 0 on success
600  * AVERROR(EINVAL) for invalid mask values
601  */
602 int av_channel_layout_from_mask(AVChannelLayout *channel_layout, uint64_t mask);
603 
604 /**
605  * Initialize a channel layout from a given string description.
606  * The input string can be represented by:
607  * - the formal channel layout name (returned by av_channel_layout_describe())
608  * - single or multiple channel names (returned by av_channel_name(), eg. "FL",
609  * or concatenated with "+", each optionally containing a custom name after
610  * a "@", eg. "FL@Left+FR@Right+LFE")
611  * - a decimal or hexadecimal value of a native channel layout (eg. "4" or "0x4")
612  * - the number of channels with default layout (eg. "4c")
613  * - the number of unordered channels (eg. "4C" or "4 channels")
614  * - the ambisonic order followed by optional non-diegetic channels (eg.
615  * "ambisonic 2+stereo")
616  *
617  * @param channel_layout input channel layout
618  * @param str string describing the channel layout
619  * @return 0 channel layout was detected, AVERROR_INVALIDATATA otherwise
620  */
622  const char *str);
623 
624 /**
625  * Get the default channel layout for a given number of channels.
626  *
627  * @param ch_layout the layout structure to be initialized
628  * @param nb_channels number of channels
629  */
630 void av_channel_layout_default(AVChannelLayout *ch_layout, int nb_channels);
631 
632 /**
633  * Iterate over all standard channel layouts.
634  *
635  * @param opaque a pointer where libavutil will store the iteration state. Must
636  * point to NULL to start the iteration.
637  *
638  * @return the standard channel layout or NULL when the iteration is
639  * finished
640  */
642 
643 /**
644  * Free any allocated data in the channel layout and reset the channel
645  * count to 0.
646  *
647  * @param channel_layout the layout structure to be uninitialized
648  */
650 
651 /**
652  * Make a copy of a channel layout. This differs from just assigning src to dst
653  * in that it allocates and copies the map for AV_CHANNEL_ORDER_CUSTOM.
654  *
655  * @note the destination channel_layout will be always uninitialized before copy.
656  *
657  * @param dst destination channel layout
658  * @param src source channel layout
659  * @return 0 on success, a negative AVERROR on error.
660  */
662 
663 /**
664  * Get a human-readable string describing the channel layout properties.
665  * The string will be in the same format that is accepted by
666  * @ref av_channel_layout_from_string(), allowing to rebuild the same
667  * channel layout, except for opaque pointers.
668  *
669  * @param channel_layout channel layout to be described
670  * @param buf pre-allocated buffer where to put the generated string
671  * @param buf_size size in bytes of the buffer.
672  * @return amount of bytes needed to hold the output string, or a negative AVERROR
673  * on failure. If the returned value is bigger than buf_size, then the
674  * string was truncated.
675  */
676 int av_channel_layout_describe(const AVChannelLayout *channel_layout,
677  char *buf, size_t buf_size);
678 
679 /**
680  * bprint variant of av_channel_layout_describe().
681  *
682  * @note the string will be appended to the bprint buffer.
683  * @return 0 on success, or a negative AVERROR value on failure.
684  */
686  struct AVBPrint *bp);
687 
688 /**
689  * Get the channel with the given index in a channel layout.
690  *
691  * @param channel_layout input channel layout
692  * @param idx index of the channel
693  * @return channel with the index idx in channel_layout on success or
694  * AV_CHAN_NONE on failure (if idx is not valid or the channel order is
695  * unspecified)
696  */
697 enum AVChannel
698 av_channel_layout_channel_from_index(const AVChannelLayout *channel_layout, unsigned int idx);
699 
700 /**
701  * Get the index of a given channel in a channel layout. In case multiple
702  * channels are found, only the first match will be returned.
703  *
704  * @param channel_layout input channel layout
705  * @param channel the channel whose index to obtain
706  * @return index of channel in channel_layout on success or a negative number if
707  * channel is not present in channel_layout.
708  */
710  enum AVChannel channel);
711 
712 /**
713  * Get the index in a channel layout of a channel described by the given string.
714  * In case multiple channels are found, only the first match will be returned.
715  *
716  * This function accepts channel names in the same format as
717  * @ref av_channel_from_string().
718  *
719  * @param channel_layout input channel layout
720  * @param name string describing the channel whose index to obtain
721  * @return a channel index described by the given string, or a negative AVERROR
722  * value.
723  */
725  const char *name);
726 
727 /**
728  * Get a channel described by the given string.
729  *
730  * This function accepts channel names in the same format as
731  * @ref av_channel_from_string().
732  *
733  * @param channel_layout input channel layout
734  * @param name string describing the channel to obtain
735  * @return a channel described by the given string in channel_layout on success
736  * or AV_CHAN_NONE on failure (if the string is not valid or the channel
737  * order is unspecified)
738  */
739 enum AVChannel
741  const char *name);
742 
743 /**
744  * Find out what channels from a given set are present in a channel layout,
745  * without regard for their positions.
746  *
747  * @param channel_layout input channel layout
748  * @param mask a combination of AV_CH_* representing a set of channels
749  * @return a bitfield representing all the channels from mask that are present
750  * in channel_layout
751  */
752 uint64_t av_channel_layout_subset(const AVChannelLayout *channel_layout,
753  uint64_t mask);
754 
755 /**
756  * Check whether a channel layout is valid, i.e. can possibly describe audio
757  * data.
758  *
759  * @param channel_layout input channel layout
760  * @return 1 if channel_layout is valid, 0 otherwise.
761  */
762 int av_channel_layout_check(const AVChannelLayout *channel_layout);
763 
764 /**
765  * Check whether two channel layouts are semantically the same, i.e. the same
766  * channels are present on the same positions in both.
767  *
768  * If one of the channel layouts is AV_CHANNEL_ORDER_UNSPEC, while the other is
769  * not, they are considered to be unequal. If both are AV_CHANNEL_ORDER_UNSPEC,
770  * they are considered equal iff the channel counts are the same in both.
771  *
772  * @param chl input channel layout
773  * @param chl1 input channel layout
774  * @return 0 if chl and chl1 are equal, 1 if they are not equal. A negative
775  * AVERROR code if one or both are invalid.
776  */
778 
779 /**
780  * @}
781  */
782 
783 #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
char * str
Buffer to print data progressively.
Definition: bprint.h:99
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.