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| /* | |
| * Copyright (c) 2006 Michael Niedermayer <[email protected]> | |
| * 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 | |
| */ | |
| /** | |
| * @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_SILENCE) | |
| * 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, | |
| }; | |
| /** | |
| * @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. | |
| * | |
| * @{ | |
| */ | |
| /** Channel mask value used for AVCodecContext.request_channel_layout | |
| to indicate that the user requests the channel order of the decoder output | |
| to be the native codec channel order. | |
| @deprecated channel order is now indicated in a special field in | |
| AVChannelLayout | |
| */ | |
| /** | |
| * @} | |
| * @defgroup channel_mask_c Audio channel layouts | |
| * @{ | |
| * */ | |
| 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; | |
| /** | |
| * @name Common pre-defined channel layouts | |
| * @{ | |
| */ | |
| /** @} */ | |
| struct AVBPrint; | |
| /** | |
| * @name Deprecated Functions | |
| * @{ | |
| */ | |
| /** | |
| * Return a channel layout id that matches name, or 0 if no match is found. | |
| * | |
| * name can be one or several of the following notations, | |
| * separated by '+' or '|': | |
| * - the name of an usual channel layout (mono, stereo, 4.0, quad, 5.0, | |
| * 5.0(side), 5.1, 5.1(side), 7.1, 7.1(wide), downmix); | |
| * - the name of a single channel (FL, FR, FC, LFE, BL, BR, FLC, FRC, BC, | |
| * SL, SR, TC, TFL, TFC, TFR, TBL, TBC, TBR, DL, DR); | |
| * - a number of channels, in decimal, followed by 'c', yielding | |
| * the default channel layout for that number of channels (@see | |
| * av_get_default_channel_layout); | |
| * - a channel layout mask, in hexadecimal starting with "0x" (see the | |
| * AV_CH_* macros). | |
| * | |
| * Example: "stereo+FC" = "2c+FC" = "2c+1c" = "0x7" | |
| * | |
| * @deprecated use av_channel_layout_from_string() | |
| */ | |
| attribute_deprecated | |
| uint64_t av_get_channel_layout(const char *name); | |
| /** | |
| * Return a channel layout and the number of channels based on the specified name. | |
| * | |
| * This function is similar to (@see av_get_channel_layout), but can also parse | |
| * unknown channel layout specifications. | |
| * | |
| * @param[in] name channel layout specification string | |
| * @param[out] channel_layout parsed channel layout (0 if unknown) | |
| * @param[out] nb_channels number of channels | |
| * | |
| * @return 0 on success, AVERROR(EINVAL) if the parsing fails. | |
| * @deprecated use av_channel_layout_from_string() | |
| */ | |
| attribute_deprecated | |
| int av_get_extended_channel_layout(const char *name, uint64_t* channel_layout, int* nb_channels); | |
| /** | |
| * Return a description of a channel layout. | |
| * If nb_channels is <= 0, it is guessed from the channel_layout. | |
| * | |
| * @param buf put here the string containing the channel layout | |
| * @param buf_size size in bytes of the buffer | |
| * @param nb_channels number of channels | |
| * @param channel_layout channel layout bitset | |
| * @deprecated use av_channel_layout_describe() | |
| */ | |
| attribute_deprecated | |
| void av_get_channel_layout_string(char *buf, int buf_size, int nb_channels, uint64_t channel_layout); | |
| /** | |
| * Append a description of a channel layout to a bprint buffer. | |
| * @deprecated use av_channel_layout_describe() | |
| */ | |
| attribute_deprecated | |
| void av_bprint_channel_layout(struct AVBPrint *bp, int nb_channels, uint64_t channel_layout); | |
| /** | |
| * Return the number of channels in the channel layout. | |
| * @deprecated use AVChannelLayout.nb_channels | |
| */ | |
| attribute_deprecated | |
| int av_get_channel_layout_nb_channels(uint64_t channel_layout); | |
| /** | |
| * Return default channel layout for a given number of channels. | |
| * | |
| * @deprecated use av_channel_layout_default() | |
| */ | |
| attribute_deprecated | |
| int64_t av_get_default_channel_layout(int nb_channels); | |
| /** | |
| * Get the index of a channel in channel_layout. | |
| * | |
| * @param channel_layout channel layout bitset | |
| * @param channel a channel layout describing exactly one channel which must be | |
| * present in channel_layout. | |
| * | |
| * @return index of channel in channel_layout on success, a negative AVERROR | |
| * on error. | |
| * | |
| * @deprecated use av_channel_layout_index_from_channel() | |
| */ | |
| attribute_deprecated | |
| int av_get_channel_layout_channel_index(uint64_t channel_layout, | |
| uint64_t channel); | |
| /** | |
| * Get the channel with the given index in channel_layout. | |
| * @deprecated use av_channel_layout_channel_from_index() | |
| */ | |
| attribute_deprecated | |
| uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index); | |
| /** | |
| * Get the name of a given channel. | |
| * | |
| * @return channel name on success, NULL on error. | |
| * | |
| * @deprecated use av_channel_name() | |
| */ | |
| attribute_deprecated | |
| const char *av_get_channel_name(uint64_t channel); | |
| /** | |
| * Get the description of a given channel. | |
| * | |
| * @param channel a channel layout with a single channel | |
| * @return channel description on success, NULL on error | |
| * @deprecated use av_channel_description() | |
| */ | |
| attribute_deprecated | |
| const char *av_get_channel_description(uint64_t channel); | |
| /** | |
| * Get the value and name of a standard channel layout. | |
| * | |
| * @param[in] index index in an internal list, starting at 0 | |
| * @param[out] layout channel layout mask | |
| * @param[out] name name of the layout | |
| * @return 0 if the layout exists, | |
| * <0 if index is beyond the limits | |
| * @deprecated use av_channel_layout_standard() | |
| */ | |
| attribute_deprecated | |
| int av_get_standard_channel_layout(unsigned index, uint64_t *layout, | |
| const char **name); | |
| /** | |
| * @} | |
| */ | |
| /** | |
| * 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 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") | |
| * | |
| * @param channel_layout input channel layout | |
| * @param str string describing the channel layout | |
| * @return 0 channel layout was detected, AVERROR_INVALIDATATA otherwise | |
| */ | |
| 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); | |
| /** | |
| * @} | |
| */ | |