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FFmpeg/libavutil/channel_layout.h
Marton Balint a688fbfb88 avutil/channel_layout: fix some (un)initialization issues in av_channel_layout_from_string() 
Also make initialization/uninitialization behaviour more explicit in the docs,
and make sure we do not leak a channel map on error.

Signed-off-by: Marton Balint <cus@passwd.hu>
2024-03-16 19:49:39 +01:00

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/*
* Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
* Copyright (c) 2008 Peter Ross
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVUTIL_CHANNEL_LAYOUT_H
#define AVUTIL_CHANNEL_LAYOUT_H
#include <stdint.h>
#include <stdlib.h>
#include "version.h"
#include "attributes.h"
/**
* @file
* @ingroup lavu_audio_channels
* Public libavutil channel layout APIs header.
*/
/**
* @defgroup lavu_audio_channels Audio channels
* @ingroup lavu_audio
*
* Audio channel layout utility functions
*
* @{
*/
enum AVChannel {
///< Invalid channel index
AV_CHAN_NONE = -1,
AV_CHAN_FRONT_LEFT,
AV_CHAN_FRONT_RIGHT,
AV_CHAN_FRONT_CENTER,
AV_CHAN_LOW_FREQUENCY,
AV_CHAN_BACK_LEFT,
AV_CHAN_BACK_RIGHT,
AV_CHAN_FRONT_LEFT_OF_CENTER,
AV_CHAN_FRONT_RIGHT_OF_CENTER,
AV_CHAN_BACK_CENTER,
AV_CHAN_SIDE_LEFT,
AV_CHAN_SIDE_RIGHT,
AV_CHAN_TOP_CENTER,
AV_CHAN_TOP_FRONT_LEFT,
AV_CHAN_TOP_FRONT_CENTER,
AV_CHAN_TOP_FRONT_RIGHT,
AV_CHAN_TOP_BACK_LEFT,
AV_CHAN_TOP_BACK_CENTER,
AV_CHAN_TOP_BACK_RIGHT,
/** Stereo downmix. */
AV_CHAN_STEREO_LEFT = 29,
/** See above. */
AV_CHAN_STEREO_RIGHT,
AV_CHAN_WIDE_LEFT,
AV_CHAN_WIDE_RIGHT,
AV_CHAN_SURROUND_DIRECT_LEFT,
AV_CHAN_SURROUND_DIRECT_RIGHT,
AV_CHAN_LOW_FREQUENCY_2,
AV_CHAN_TOP_SIDE_LEFT,
AV_CHAN_TOP_SIDE_RIGHT,
AV_CHAN_BOTTOM_FRONT_CENTER,
AV_CHAN_BOTTOM_FRONT_LEFT,
AV_CHAN_BOTTOM_FRONT_RIGHT,
/** Channel is empty can be safely skipped. */
AV_CHAN_UNUSED = 0x200,
/** Channel contains data, but its position is unknown. */
AV_CHAN_UNKNOWN = 0x300,
/**
* Range of channels between AV_CHAN_AMBISONIC_BASE and
* AV_CHAN_AMBISONIC_END represent Ambisonic components using the ACN system.
*
* Given a channel id `<i>` between AV_CHAN_AMBISONIC_BASE and
* AV_CHAN_AMBISONIC_END (inclusive), the ACN index of the channel `<n>` is
* `<n> = <i> - AV_CHAN_AMBISONIC_BASE`.
*
* @note these values are only used for AV_CHANNEL_ORDER_CUSTOM channel
* orderings, the AV_CHANNEL_ORDER_AMBISONIC ordering orders the channels
* implicitly by their position in the stream.
*/
AV_CHAN_AMBISONIC_BASE = 0x400,
// leave space for 1024 ids, which correspond to maximum order-32 harmonics,
// which should be enough for the foreseeable use cases
AV_CHAN_AMBISONIC_END = 0x7ff,
};
enum AVChannelOrder {
/**
* Only the channel count is specified, without any further information
* about the channel order.
*/
AV_CHANNEL_ORDER_UNSPEC,
/**
* The native channel order, i.e. the channels are in the same order in
* which they are defined in the AVChannel enum. This supports up to 63
* different channels.
*/
AV_CHANNEL_ORDER_NATIVE,
/**
* The channel order does not correspond to any other predefined order and
* is stored as an explicit map. For example, this could be used to support
* layouts with 64 or more channels, or with empty/skipped (AV_CHAN_UNUSED)
* channels at arbitrary positions.
*/
AV_CHANNEL_ORDER_CUSTOM,
/**
* The audio is represented as the decomposition of the sound field into
* spherical harmonics. Each channel corresponds to a single expansion
* component. Channels are ordered according to ACN (Ambisonic Channel
* Number).
*
* The channel with the index n in the stream contains the spherical
* harmonic of degree l and order m given by
* @code{.unparsed}
* l = floor(sqrt(n)),
* m = n - l * (l + 1).
* @endcode
*
* Conversely given a spherical harmonic of degree l and order m, the
* corresponding channel index n is given by
* @code{.unparsed}
* n = l * (l + 1) + m.
* @endcode
*
* Normalization is assumed to be SN3D (Schmidt Semi-Normalization)
* as defined in AmbiX format $ 2.1.
*/
AV_CHANNEL_ORDER_AMBISONIC,
/**
* Number of channel orders, not part of ABI/API
*/
FF_CHANNEL_ORDER_NB
};
/**
* @defgroup channel_masks Audio channel masks
*
* A channel layout is a 64-bits integer with a bit set for every channel.
* The number of bits set must be equal to the number of channels.
* The value 0 means that the channel layout is not known.
* @note this data structure is not powerful enough to handle channels
* combinations that have the same channel multiple times, such as
* dual-mono.
*
* @{
*/
#define AV_CH_FRONT_LEFT (1ULL << AV_CHAN_FRONT_LEFT )
#define AV_CH_FRONT_RIGHT (1ULL << AV_CHAN_FRONT_RIGHT )
#define AV_CH_FRONT_CENTER (1ULL << AV_CHAN_FRONT_CENTER )
#define AV_CH_LOW_FREQUENCY (1ULL << AV_CHAN_LOW_FREQUENCY )
#define AV_CH_BACK_LEFT (1ULL << AV_CHAN_BACK_LEFT )
#define AV_CH_BACK_RIGHT (1ULL << AV_CHAN_BACK_RIGHT )
#define AV_CH_FRONT_LEFT_OF_CENTER (1ULL << AV_CHAN_FRONT_LEFT_OF_CENTER )
#define AV_CH_FRONT_RIGHT_OF_CENTER (1ULL << AV_CHAN_FRONT_RIGHT_OF_CENTER)
#define AV_CH_BACK_CENTER (1ULL << AV_CHAN_BACK_CENTER )
#define AV_CH_SIDE_LEFT (1ULL << AV_CHAN_SIDE_LEFT )
#define AV_CH_SIDE_RIGHT (1ULL << AV_CHAN_SIDE_RIGHT )
#define AV_CH_TOP_CENTER (1ULL << AV_CHAN_TOP_CENTER )
#define AV_CH_TOP_FRONT_LEFT (1ULL << AV_CHAN_TOP_FRONT_LEFT )
#define AV_CH_TOP_FRONT_CENTER (1ULL << AV_CHAN_TOP_FRONT_CENTER )
#define AV_CH_TOP_FRONT_RIGHT (1ULL << AV_CHAN_TOP_FRONT_RIGHT )
#define AV_CH_TOP_BACK_LEFT (1ULL << AV_CHAN_TOP_BACK_LEFT )
#define AV_CH_TOP_BACK_CENTER (1ULL << AV_CHAN_TOP_BACK_CENTER )
#define AV_CH_TOP_BACK_RIGHT (1ULL << AV_CHAN_TOP_BACK_RIGHT )
#define AV_CH_STEREO_LEFT (1ULL << AV_CHAN_STEREO_LEFT )
#define AV_CH_STEREO_RIGHT (1ULL << AV_CHAN_STEREO_RIGHT )
#define AV_CH_WIDE_LEFT (1ULL << AV_CHAN_WIDE_LEFT )
#define AV_CH_WIDE_RIGHT (1ULL << AV_CHAN_WIDE_RIGHT )
#define AV_CH_SURROUND_DIRECT_LEFT (1ULL << AV_CHAN_SURROUND_DIRECT_LEFT )
#define AV_CH_SURROUND_DIRECT_RIGHT (1ULL << AV_CHAN_SURROUND_DIRECT_RIGHT)
#define AV_CH_LOW_FREQUENCY_2 (1ULL << AV_CHAN_LOW_FREQUENCY_2 )
#define AV_CH_TOP_SIDE_LEFT (1ULL << AV_CHAN_TOP_SIDE_LEFT )
#define AV_CH_TOP_SIDE_RIGHT (1ULL << AV_CHAN_TOP_SIDE_RIGHT )
#define AV_CH_BOTTOM_FRONT_CENTER (1ULL << AV_CHAN_BOTTOM_FRONT_CENTER )
#define AV_CH_BOTTOM_FRONT_LEFT (1ULL << AV_CHAN_BOTTOM_FRONT_LEFT )
#define AV_CH_BOTTOM_FRONT_RIGHT (1ULL << AV_CHAN_BOTTOM_FRONT_RIGHT )
/**
* @}
* @defgroup channel_mask_c Audio channel layouts
* @{
* */
#define AV_CH_LAYOUT_MONO (AV_CH_FRONT_CENTER)
#define AV_CH_LAYOUT_STEREO (AV_CH_FRONT_LEFT|AV_CH_FRONT_RIGHT)
#define AV_CH_LAYOUT_2POINT1 (AV_CH_LAYOUT_STEREO|AV_CH_LOW_FREQUENCY)
#define AV_CH_LAYOUT_2_1 (AV_CH_LAYOUT_STEREO|AV_CH_BACK_CENTER)
#define AV_CH_LAYOUT_SURROUND (AV_CH_LAYOUT_STEREO|AV_CH_FRONT_CENTER)
#define AV_CH_LAYOUT_3POINT1 (AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY)
#define AV_CH_LAYOUT_4POINT0 (AV_CH_LAYOUT_SURROUND|AV_CH_BACK_CENTER)
#define AV_CH_LAYOUT_4POINT1 (AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY)
#define AV_CH_LAYOUT_2_2 (AV_CH_LAYOUT_STEREO|AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT)
#define AV_CH_LAYOUT_QUAD (AV_CH_LAYOUT_STEREO|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
#define AV_CH_LAYOUT_5POINT0 (AV_CH_LAYOUT_SURROUND|AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT)
#define AV_CH_LAYOUT_5POINT1 (AV_CH_LAYOUT_5POINT0|AV_CH_LOW_FREQUENCY)
#define AV_CH_LAYOUT_5POINT0_BACK (AV_CH_LAYOUT_SURROUND|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
#define AV_CH_LAYOUT_5POINT1_BACK (AV_CH_LAYOUT_5POINT0_BACK|AV_CH_LOW_FREQUENCY)
#define AV_CH_LAYOUT_6POINT0 (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_CENTER)
#define AV_CH_LAYOUT_6POINT0_FRONT (AV_CH_LAYOUT_2_2|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
#define AV_CH_LAYOUT_HEXAGONAL (AV_CH_LAYOUT_5POINT0_BACK|AV_CH_BACK_CENTER)
#define AV_CH_LAYOUT_3POINT1POINT2 (AV_CH_LAYOUT_3POINT1|AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT)
#define AV_CH_LAYOUT_6POINT1 (AV_CH_LAYOUT_5POINT1|AV_CH_BACK_CENTER)
#define AV_CH_LAYOUT_6POINT1_BACK (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_BACK_CENTER)
#define AV_CH_LAYOUT_6POINT1_FRONT (AV_CH_LAYOUT_6POINT0_FRONT|AV_CH_LOW_FREQUENCY)
#define AV_CH_LAYOUT_7POINT0 (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
#define AV_CH_LAYOUT_7POINT0_FRONT (AV_CH_LAYOUT_5POINT0|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
#define AV_CH_LAYOUT_7POINT1 (AV_CH_LAYOUT_5POINT1|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)
#define AV_CH_LAYOUT_7POINT1_WIDE (AV_CH_LAYOUT_5POINT1|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
#define AV_CH_LAYOUT_7POINT1_WIDE_BACK (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
#define AV_CH_LAYOUT_5POINT1POINT2_BACK (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT)
#define AV_CH_LAYOUT_OCTAGONAL (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_LEFT|AV_CH_BACK_CENTER|AV_CH_BACK_RIGHT)
#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)
#define AV_CH_LAYOUT_5POINT1POINT4_BACK (AV_CH_LAYOUT_5POINT1POINT2_BACK|AV_CH_TOP_BACK_LEFT|AV_CH_TOP_BACK_RIGHT)
#define AV_CH_LAYOUT_7POINT1POINT2 (AV_CH_LAYOUT_7POINT1|AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT)
#define AV_CH_LAYOUT_7POINT1POINT4_BACK (AV_CH_LAYOUT_7POINT1POINT2|AV_CH_TOP_BACK_LEFT|AV_CH_TOP_BACK_RIGHT)
#define AV_CH_LAYOUT_7POINT2POINT3 (AV_CH_LAYOUT_7POINT1POINT2|AV_CH_TOP_BACK_CENTER|AV_CH_LOW_FREQUENCY_2)
#define AV_CH_LAYOUT_9POINT1POINT4_BACK (AV_CH_LAYOUT_7POINT1POINT4_BACK|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)
#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)
#define AV_CH_LAYOUT_STEREO_DOWNMIX (AV_CH_STEREO_LEFT|AV_CH_STEREO_RIGHT)
#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)
#define AV_CH_LAYOUT_7POINT1_TOP_BACK AV_CH_LAYOUT_5POINT1POINT2_BACK
enum AVMatrixEncoding {
AV_MATRIX_ENCODING_NONE,
AV_MATRIX_ENCODING_DOLBY,
AV_MATRIX_ENCODING_DPLII,
AV_MATRIX_ENCODING_DPLIIX,
AV_MATRIX_ENCODING_DPLIIZ,
AV_MATRIX_ENCODING_DOLBYEX,
AV_MATRIX_ENCODING_DOLBYHEADPHONE,
AV_MATRIX_ENCODING_NB
};
/**
* @}
*/
/**
* An AVChannelCustom defines a single channel within a custom order layout
*
* Unlike most structures in FFmpeg, sizeof(AVChannelCustom) is a part of the
* public ABI.
*
* No new fields may be added to it without a major version bump.
*/
typedef struct AVChannelCustom {
enum AVChannel id;
char name[16];
void *opaque;
} AVChannelCustom;
/**
* An AVChannelLayout holds information about the channel layout of audio data.
*
* A channel layout here is defined as a set of channels ordered in a specific
* way (unless the channel order is AV_CHANNEL_ORDER_UNSPEC, in which case an
* AVChannelLayout carries only the channel count).
* All orders may be treated as if they were AV_CHANNEL_ORDER_UNSPEC by
* ignoring everything but the channel count, as long as av_channel_layout_check()
* considers they are valid.
*
* Unlike most structures in FFmpeg, sizeof(AVChannelLayout) is a part of the
* public ABI and may be used by the caller. E.g. it may be allocated on stack
* or embedded in caller-defined structs.
*
* AVChannelLayout can be initialized as follows:
* - default initialization with {0}, followed by setting all used fields
* correctly;
* - by assigning one of the predefined AV_CHANNEL_LAYOUT_* initializers;
* - with a constructor function, such as av_channel_layout_default(),
* av_channel_layout_from_mask() or av_channel_layout_from_string().
*
* The channel layout must be unitialized with av_channel_layout_uninit()
*
* Copying an AVChannelLayout via assigning is forbidden,
* av_channel_layout_copy() must be used instead (and its return value should
* be checked)
*
* No new fields may be added to it without a major version bump, except for
* new elements of the union fitting in sizeof(uint64_t).
*/
typedef struct AVChannelLayout {
/**
* Channel order used in this layout.
* This is a mandatory field.
*/
enum AVChannelOrder order;
/**
* Number of channels in this layout. Mandatory field.
*/
int nb_channels;
/**
* Details about which channels are present in this layout.
* For AV_CHANNEL_ORDER_UNSPEC, this field is undefined and must not be
* used.
*/
union {
/**
* This member must be used for AV_CHANNEL_ORDER_NATIVE, and may be used
* for AV_CHANNEL_ORDER_AMBISONIC to signal non-diegetic channels.
* It is a bitmask, where the position of each set bit means that the
* AVChannel with the corresponding value is present.
*
* I.e. when (mask & (1 << AV_CHAN_FOO)) is non-zero, then AV_CHAN_FOO
* is present in the layout. Otherwise it is not present.
*
* @note when a channel layout using a bitmask is constructed or
* modified manually (i.e. not using any of the av_channel_layout_*
* functions), the code doing it must ensure that the number of set bits
* is equal to nb_channels.
*/
uint64_t mask;
/**
* This member must be used when the channel order is
* AV_CHANNEL_ORDER_CUSTOM. It is a nb_channels-sized array, with each
* element signalling the presence of the AVChannel with the
* corresponding value in map[i].id.
*
* I.e. when map[i].id is equal to AV_CHAN_FOO, then AV_CH_FOO is the
* i-th channel in the audio data.
*
* When map[i].id is in the range between AV_CHAN_AMBISONIC_BASE and
* AV_CHAN_AMBISONIC_END (inclusive), the channel contains an ambisonic
* component with ACN index (as defined above)
* n = map[i].id - AV_CHAN_AMBISONIC_BASE.
*
* map[i].name may be filled with a 0-terminated string, in which case
* it will be used for the purpose of identifying the channel with the
* convenience functions below. Otherise it must be zeroed.
*/
AVChannelCustom *map;
} u;
/**
* For some private data of the user.
*/
void *opaque;
} AVChannelLayout;
/**
* Macro to define native channel layouts
*
* @note This doesn't use designated initializers for compatibility with C++ 17 and older.
*/
#define AV_CHANNEL_LAYOUT_MASK(nb, m) \
{ /* .order */ AV_CHANNEL_ORDER_NATIVE, \
/* .nb_channels */ (nb), \
/* .u.mask */ { m }, \
/* .opaque */ NULL }
/**
* @name Common pre-defined channel layouts
* @{
*/
#define AV_CHANNEL_LAYOUT_MONO AV_CHANNEL_LAYOUT_MASK(1, AV_CH_LAYOUT_MONO)
#define AV_CHANNEL_LAYOUT_STEREO AV_CHANNEL_LAYOUT_MASK(2, AV_CH_LAYOUT_STEREO)
#define AV_CHANNEL_LAYOUT_2POINT1 AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_2POINT1)
#define AV_CHANNEL_LAYOUT_2_1 AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_2_1)
#define AV_CHANNEL_LAYOUT_SURROUND AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_SURROUND)
#define AV_CHANNEL_LAYOUT_3POINT1 AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_3POINT1)
#define AV_CHANNEL_LAYOUT_4POINT0 AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_4POINT0)
#define AV_CHANNEL_LAYOUT_4POINT1 AV_CHANNEL_LAYOUT_MASK(5, AV_CH_LAYOUT_4POINT1)
#define AV_CHANNEL_LAYOUT_2_2 AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_2_2)
#define AV_CHANNEL_LAYOUT_QUAD AV_CHANNEL_LAYOUT_MASK(4, AV_CH_LAYOUT_QUAD)
#define AV_CHANNEL_LAYOUT_5POINT0 AV_CHANNEL_LAYOUT_MASK(5, AV_CH_LAYOUT_5POINT0)
#define AV_CHANNEL_LAYOUT_5POINT1 AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_5POINT1)
#define AV_CHANNEL_LAYOUT_5POINT0_BACK AV_CHANNEL_LAYOUT_MASK(5, AV_CH_LAYOUT_5POINT0_BACK)
#define AV_CHANNEL_LAYOUT_5POINT1_BACK AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_5POINT1_BACK)
#define AV_CHANNEL_LAYOUT_6POINT0 AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_6POINT0)
#define AV_CHANNEL_LAYOUT_6POINT0_FRONT AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_6POINT0_FRONT)
#define AV_CHANNEL_LAYOUT_3POINT1POINT2 AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_3POINT1POINT2)
#define AV_CHANNEL_LAYOUT_HEXAGONAL AV_CHANNEL_LAYOUT_MASK(6, AV_CH_LAYOUT_HEXAGONAL)
#define AV_CHANNEL_LAYOUT_6POINT1 AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_6POINT1)
#define AV_CHANNEL_LAYOUT_6POINT1_BACK AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_6POINT1_BACK)
#define AV_CHANNEL_LAYOUT_6POINT1_FRONT AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_6POINT1_FRONT)
#define AV_CHANNEL_LAYOUT_7POINT0 AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_7POINT0)
#define AV_CHANNEL_LAYOUT_7POINT0_FRONT AV_CHANNEL_LAYOUT_MASK(7, AV_CH_LAYOUT_7POINT0_FRONT)
#define AV_CHANNEL_LAYOUT_7POINT1 AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_7POINT1)
#define AV_CHANNEL_LAYOUT_7POINT1_WIDE AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_7POINT1_WIDE)
#define AV_CHANNEL_LAYOUT_7POINT1_WIDE_BACK AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_7POINT1_WIDE_BACK)
#define AV_CHANNEL_LAYOUT_5POINT1POINT2_BACK AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_5POINT1POINT2_BACK)
#define AV_CHANNEL_LAYOUT_OCTAGONAL AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_OCTAGONAL)
#define AV_CHANNEL_LAYOUT_CUBE AV_CHANNEL_LAYOUT_MASK(8, AV_CH_LAYOUT_CUBE)
#define AV_CHANNEL_LAYOUT_5POINT1POINT4_BACK AV_CHANNEL_LAYOUT_MASK(10, AV_CH_LAYOUT_5POINT1POINT4_BACK)
#define AV_CHANNEL_LAYOUT_7POINT1POINT2 AV_CHANNEL_LAYOUT_MASK(10, AV_CH_LAYOUT_7POINT1POINT2)
#define AV_CHANNEL_LAYOUT_7POINT1POINT4_BACK AV_CHANNEL_LAYOUT_MASK(12, AV_CH_LAYOUT_7POINT1POINT4_BACK)
#define AV_CHANNEL_LAYOUT_7POINT2POINT3 AV_CHANNEL_LAYOUT_MASK(12, AV_CH_LAYOUT_7POINT2POINT3)
#define AV_CHANNEL_LAYOUT_9POINT1POINT4_BACK AV_CHANNEL_LAYOUT_MASK(14, AV_CH_LAYOUT_9POINT1POINT4_BACK)
#define AV_CHANNEL_LAYOUT_HEXADECAGONAL AV_CHANNEL_LAYOUT_MASK(16, AV_CH_LAYOUT_HEXADECAGONAL)
#define AV_CHANNEL_LAYOUT_STEREO_DOWNMIX AV_CHANNEL_LAYOUT_MASK(2, AV_CH_LAYOUT_STEREO_DOWNMIX)
#define AV_CHANNEL_LAYOUT_22POINT2 AV_CHANNEL_LAYOUT_MASK(24, AV_CH_LAYOUT_22POINT2)
#define AV_CHANNEL_LAYOUT_7POINT1_TOP_BACK AV_CHANNEL_LAYOUT_5POINT1POINT2_BACK
#define AV_CHANNEL_LAYOUT_AMBISONIC_FIRST_ORDER \
{ /* .order */ AV_CHANNEL_ORDER_AMBISONIC, \
/* .nb_channels */ 4, \
/* .u.mask */ { 0 }, \
/* .opaque */ NULL }
/** @} */
struct AVBPrint;
/**
* Get a human readable string in an abbreviated form describing a given channel.
* This is the inverse function of @ref av_channel_from_string().
*
* @param buf pre-allocated buffer where to put the generated string
* @param buf_size size in bytes of the buffer.
* @param channel the AVChannel whose name to get
* @return amount of bytes needed to hold the output string, or a negative AVERROR
* on failure. If the returned value is bigger than buf_size, then the
* string was truncated.
*/
int av_channel_name(char *buf, size_t buf_size, enum AVChannel channel);
/**
* bprint variant of av_channel_name().
*
* @note the string will be appended to the bprint buffer.
*/
void av_channel_name_bprint(struct AVBPrint *bp, enum AVChannel channel_id);
/**
* Get a human readable string describing a given channel.
*
* @param buf pre-allocated buffer where to put the generated string
* @param buf_size size in bytes of the buffer.
* @param channel the AVChannel whose description to get
* @return amount of bytes needed to hold the output string, or a negative AVERROR
* on failure. If the returned value is bigger than buf_size, then the
* string was truncated.
*/
int av_channel_description(char *buf, size_t buf_size, enum AVChannel channel);
/**
* bprint variant of av_channel_description().
*
* @note the string will be appended to the bprint buffer.
*/
void av_channel_description_bprint(struct AVBPrint *bp, enum AVChannel channel_id);
/**
* This is the inverse function of @ref av_channel_name().
*
* @return the channel with the given name
* AV_CHAN_NONE when name does not identify a known channel
*/
enum AVChannel av_channel_from_string(const char *name);
/**
* Initialize a custom channel layout with the specified number of channels.
* The channel map will be allocated and the designation of all channels will
* be set to AV_CHAN_UNKNOWN.
*
* This is only a convenience helper function, a custom channel layout can also
* be constructed without using this.
*
* @param channel_layout the layout structure to be initialized
* @param nb_channels the number of channels
*
* @return 0 on success
* AVERROR(EINVAL) if the number of channels <= 0
* AVERROR(ENOMEM) if the channel map could not be allocated
*/
int av_channel_layout_custom_init(AVChannelLayout *channel_layout, int nb_channels);
/**
* Initialize a native channel layout from a bitmask indicating which channels
* are present.
*
* @param channel_layout the layout structure to be initialized
* @param mask bitmask describing the channel layout
*
* @return 0 on success
* AVERROR(EINVAL) for invalid mask values
*/
int av_channel_layout_from_mask(AVChannelLayout *channel_layout, uint64_t mask);
/**
* Initialize a channel layout from a given string description.
* The input string can be represented by:
* - the formal channel layout name (returned by av_channel_layout_describe())
* - single or multiple channel names (returned by av_channel_name(), eg. "FL",
* or concatenated with "+", each optionally containing a custom name after
* a "@", eg. "FL@Left+FR@Right+LFE")
* - a decimal or hexadecimal value of a native channel layout (eg. "4" or "0x4")
* - the number of channels with default layout (eg. "4c")
* - the number of unordered channels (eg. "4C" or "4 channels")
* - the ambisonic order followed by optional non-diegetic channels (eg.
* "ambisonic 2+stereo")
* On error, the channel layout will remain uninitialized, but not necessarily
* untouched.
*
* @param channel_layout uninitialized channel layout for the result
* @param str string describing the channel layout
* @return 0 on success parsing the channel layout
* AVERROR(EINVAL) if an invalid channel layout string was provided
* AVERROR(ENOMEM) if there was not enough memory
*/
int av_channel_layout_from_string(AVChannelLayout *channel_layout,
const char *str);
/**
* Get the default channel layout for a given number of channels.
*
* @param ch_layout the layout structure to be initialized
* @param nb_channels number of channels
*/
void av_channel_layout_default(AVChannelLayout *ch_layout, int nb_channels);
/**
* Iterate over all standard channel layouts.
*
* @param opaque a pointer where libavutil will store the iteration state. Must
* point to NULL to start the iteration.
*
* @return the standard channel layout or NULL when the iteration is
* finished
*/
const AVChannelLayout *av_channel_layout_standard(void **opaque);
/**
* Free any allocated data in the channel layout and reset the channel
* count to 0.
*
* @param channel_layout the layout structure to be uninitialized
*/
void av_channel_layout_uninit(AVChannelLayout *channel_layout);
/**
* Make a copy of a channel layout. This differs from just assigning src to dst
* in that it allocates and copies the map for AV_CHANNEL_ORDER_CUSTOM.
*
* @note the destination channel_layout will be always uninitialized before copy.
*
* @param dst destination channel layout
* @param src source channel layout
* @return 0 on success, a negative AVERROR on error.
*/
int av_channel_layout_copy(AVChannelLayout *dst, const AVChannelLayout *src);
/**
* Get a human-readable string describing the channel layout properties.
* The string will be in the same format that is accepted by
* @ref av_channel_layout_from_string(), allowing to rebuild the same
* channel layout, except for opaque pointers.
*
* @param channel_layout channel layout to be described
* @param buf pre-allocated buffer where to put the generated string
* @param buf_size size in bytes of the buffer.
* @return amount of bytes needed to hold the output string, or a negative AVERROR
* on failure. If the returned value is bigger than buf_size, then the
* string was truncated.
*/
int av_channel_layout_describe(const AVChannelLayout *channel_layout,
char *buf, size_t buf_size);
/**
* bprint variant of av_channel_layout_describe().
*
* @note the string will be appended to the bprint buffer.
* @return 0 on success, or a negative AVERROR value on failure.
*/
int av_channel_layout_describe_bprint(const AVChannelLayout *channel_layout,
struct AVBPrint *bp);
/**
* Get the channel with the given index in a channel layout.
*
* @param channel_layout input channel layout
* @param idx index of the channel
* @return channel with the index idx in channel_layout on success or
* AV_CHAN_NONE on failure (if idx is not valid or the channel order is
* unspecified)
*/
enum AVChannel
av_channel_layout_channel_from_index(const AVChannelLayout *channel_layout, unsigned int idx);
/**
* Get the index of a given channel in a channel layout. In case multiple
* channels are found, only the first match will be returned.
*
* @param channel_layout input channel layout
* @param channel the channel whose index to obtain
* @return index of channel in channel_layout on success or a negative number if
* channel is not present in channel_layout.
*/
int av_channel_layout_index_from_channel(const AVChannelLayout *channel_layout,
enum AVChannel channel);
/**
* Get the index in a channel layout of a channel described by the given string.
* In case multiple channels are found, only the first match will be returned.
*
* This function accepts channel names in the same format as
* @ref av_channel_from_string().
*
* @param channel_layout input channel layout
* @param name string describing the channel whose index to obtain
* @return a channel index described by the given string, or a negative AVERROR
* value.
*/
int av_channel_layout_index_from_string(const AVChannelLayout *channel_layout,
const char *name);
/**
* Get a channel described by the given string.
*
* This function accepts channel names in the same format as
* @ref av_channel_from_string().
*
* @param channel_layout input channel layout
* @param name string describing the channel to obtain
* @return a channel described by the given string in channel_layout on success
* or AV_CHAN_NONE on failure (if the string is not valid or the channel
* order is unspecified)
*/
enum AVChannel
av_channel_layout_channel_from_string(const AVChannelLayout *channel_layout,
const char *name);
/**
* Find out what channels from a given set are present in a channel layout,
* without regard for their positions.
*
* @param channel_layout input channel layout
* @param mask a combination of AV_CH_* representing a set of channels
* @return a bitfield representing all the channels from mask that are present
* in channel_layout
*/
uint64_t av_channel_layout_subset(const AVChannelLayout *channel_layout,
uint64_t mask);
/**
* Check whether a channel layout is valid, i.e. can possibly describe audio
* data.
*
* @param channel_layout input channel layout
* @return 1 if channel_layout is valid, 0 otherwise.
*/
int av_channel_layout_check(const AVChannelLayout *channel_layout);
/**
* Check whether two channel layouts are semantically the same, i.e. the same
* channels are present on the same positions in both.
*
* If one of the channel layouts is AV_CHANNEL_ORDER_UNSPEC, while the other is
* not, they are considered to be unequal. If both are AV_CHANNEL_ORDER_UNSPEC,
* they are considered equal iff the channel counts are the same in both.
*
* @param chl input channel layout
* @param chl1 input channel layout
* @return 0 if chl and chl1 are equal, 1 if they are not equal. A negative
* AVERROR code if one or both are invalid.
*/
int av_channel_layout_compare(const AVChannelLayout *chl, const AVChannelLayout *chl1);
/**
* The conversion must be lossless.
*/
#define AV_CHANNEL_LAYOUT_RETYPE_FLAG_LOSSLESS (1 << 0)
/**
* The specified retype target order is ignored and the simplest possible
* (canonical) order is used for which the input layout can be losslessy
* represented.
*/
#define AV_CHANNEL_LAYOUT_RETYPE_FLAG_CANONICAL (1 << 1)
/**
* Change the AVChannelOrder of a channel layout.
*
* Change of AVChannelOrder can be either lossless or lossy. In case of a
* lossless conversion all the channel designations and the associated channel
* names (if any) are kept. On a lossy conversion the channel names and channel
* designations might be lost depending on the capabilities of the desired
* AVChannelOrder. Note that some conversions are simply not possible in which
* case this function returns AVERROR(ENOSYS).
*
* The following conversions are supported:
*
* Any -> Custom : Always possible, always lossless.
* Any -> Unspecified: Always possible, lossless if channel designations
* are all unknown and channel names are not used, lossy otherwise.
* Custom -> Ambisonic : Possible if it contains ambisonic channels with
* optional non-diegetic channels in the end. Lossy if the channels have
* custom names, lossless otherwise.
* Custom -> Native : Possible if it contains native channels in native
* order. Lossy if the channels have custom names, lossless otherwise.
*
* On error this function keeps the original channel layout untouched.
*
* @param channel_layout channel layout which will be changed
* @param order the desired channel layout order
* @param flags a combination of AV_CHANNEL_LAYOUT_RETYPE_FLAG_* constants
* @return 0 if the conversion was successful and lossless or if the channel
* layout was already in the desired order
* >0 if the conversion was successful but lossy
* AVERROR(ENOSYS) if the conversion was not possible (or would be
* lossy and AV_CHANNEL_LAYOUT_RETYPE_FLAG_LOSSLESS was specified)
* AVERROR(EINVAL), AVERROR(ENOMEM) on error
*/
int av_channel_layout_retype(AVChannelLayout *channel_layout, enum AVChannelOrder order, int flags);
/**
* @}
*/
#endif /* AVUTIL_CHANNEL_LAYOUT_H */
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