Bluetooth Audio
API Reference
- group bt_audio
Bluetooth Audio.
Defines
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BT_AUDIO_BROADCAST_ID_SIZE
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BT_AUDIO_BROADCAST_ID_MAX
Maximum broadcast ID value
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BT_AUDIO_PD_PREF_NONE
Indicates that the server have no preference for the presentation delay
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BT_AUDIO_PD_MAX
Maximum presentation delay in microseconds
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BT_AUDIO_BROADCAST_CODE_SIZE
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BT_AUDIO_CONTEXT_TYPE_ANY
Any known context.
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BT_AUDIO_UNICAST_ANNOUNCEMENT_GENERAL
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BT_AUDIO_UNICAST_ANNOUNCEMENT_TARGETED
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BT_CODEC_DATA(_type, _bytes...)
Helper to declare elements of bt_codec_data arrays.
This macro is mainly for creating an array of struct bt_codec_data elements inside bt_codec which is then passed to the likes of bt_bap_stream_config or bt_bap_stream_reconfig.
- Parameters:
_type – Type of advertising data field
_bytes – Variable number of single-byte parameters
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BT_CODEC(_id, _cid, _vid, _data, _meta)
Helper to declare bt_codec structure.
- Parameters:
_id – Codec ID
_cid – Company ID
_vid – Vendor ID
_data – Codec Specific Data in LVT format
_meta – Codec Specific Metadata in LVT format
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BT_AUDIO_LOCATION_ANY
Any known location.
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BT_CODEC_QOS(_interval, _framing, _phy, _sdu, _rtn, _latency, _pd)
Helper to declare elements of bt_codec_qos.
- Parameters:
_interval – SDU interval (usec)
_framing – Framing
_phy – Target PHY
_sdu – Maximum SDU Size
_rtn – Retransmission number
_latency – Maximum Transport Latency (msec)
_pd – Presentation Delay (usec)
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BT_CODEC_QOS_UNFRAMED(_interval, _sdu, _rtn, _latency, _pd)
Helper to declare Input Unframed bt_codec_qos.
- Parameters:
_interval – SDU interval (usec)
_sdu – Maximum SDU Size
_rtn – Retransmission number
_latency – Maximum Transport Latency (msec)
_pd – Presentation Delay (usec)
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BT_CODEC_QOS_FRAMED(_interval, _sdu, _rtn, _latency, _pd)
Helper to declare Input Framed bt_codec_qos.
- Parameters:
_interval – SDU interval (usec)
_sdu – Maximum SDU Size
_rtn – Retransmission number
_latency – Maximum Transport Latency (msec)
_pd – Presentation Delay (usec)
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BT_CODEC_QOS_PREF(_unframed_supported, _phy, _rtn, _latency, _pd_min, _pd_max, _pref_pd_min, _pref_pd_max)
Helper to declare elements of bt_codec_qos_pref.
- Parameters:
_unframed_supported – Unframed PDUs supported
_phy – Preferred Target PHY
_rtn – Preferred Retransmission number
_latency – Preferred Maximum Transport Latency (msec)
_pd_min – Minimum Presentation Delay (usec)
_pd_max – Maximum Presentation Delay (usec)
_pref_pd_min – Preferred Minimum Presentation Delay (usec)
_pref_pd_max – Preferred Maximum Presentation Delay (usec)
Enums
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enum bt_audio_context
Audio Context Type for Generic Audio.
These values are defined by the Generic Audio Assigned Numbers, bluetooth.com
Values:
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enumerator BT_AUDIO_CONTEXT_TYPE_PROHIBITED = 0
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enumerator BT_AUDIO_CONTEXT_TYPE_PROHIBITED = 0
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enum bt_audio_parental_rating
Parental rating defined by the Generic Audio assigned numbers (bluetooth.com).
The numbering scheme is aligned with Annex F of EN 300 707 v1.2.1 which defined parental rating for viewing.
Values:
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enumerator BT_AUDIO_PARENTAL_RATING_NO_RATING = 0x00
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_ANY = 0x01
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_5_OR_ABOVE = 0x02
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_6_OR_ABOVE = 0x03
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_7_OR_ABOVE = 0x04
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_8_OR_ABOVE = 0x05
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_9_OR_ABOVE = 0x06
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_10_OR_ABOVE = 0x07
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_11_OR_ABOVE = 0x08
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_12_OR_ABOVE = 0x09
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_13_OR_ABOVE = 0x0A
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_14_OR_ABOVE = 0x0B
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_15_OR_ABOVE = 0x0C
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_16_OR_ABOVE = 0x0D
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_17_OR_ABOVE = 0x0E
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enumerator BT_AUDIO_PARENTAL_RATING_AGE_18_OR_ABOVE = 0x0F
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enumerator BT_AUDIO_PARENTAL_RATING_NO_RATING = 0x00
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enum bt_audio_active_state
Audio Active State defined by the Generic Audio assigned numbers (bluetooth.com).
Values:
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enumerator BT_AUDIO_ACTIVE_STATE_DISABLED = 0x00
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enumerator BT_AUDIO_ACTIVE_STATE_ENABLED = 0x01
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enumerator BT_AUDIO_ACTIVE_STATE_DISABLED = 0x00
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enum bt_audio_metadata_type
Codec metadata type IDs.
Metadata types defined by the Generic Audio assigned numbers (bluetooth.com).
Values:
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enumerator BT_AUDIO_METADATA_TYPE_PREF_CONTEXT = 0x01
Preferred audio context.
Bitfield of preferred audio contexts. If 0, the context type is not a preferred use case for this codec configuration. See the BT_AUDIO_CONTEXT_* for valid values.
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enumerator BT_AUDIO_METADATA_TYPE_STREAM_CONTEXT = 0x02
Streaming audio context.
Bitfield of streaming audio contexts. If 0, the context type is not a preferred use case for this codec configuration. See the BT_AUDIO_CONTEXT_* for valid values.
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enumerator BT_AUDIO_METADATA_TYPE_PROGRAM_INFO = 0x03
UTF-8 encoded title or summary of stream content
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enumerator BT_AUDIO_METADATA_TYPE_STREAM_LANG = 0x04
Stream language.
3 octet lower case language code defined by ISO 639-3
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enumerator BT_AUDIO_METADATA_TYPE_CCID_LIST = 0x05
Array of 8-bit CCID values
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enumerator BT_AUDIO_METADATA_TYPE_PARENTAL_RATING = 0x06
Parental rating.
See @ref bt_audio_parental_rating for valid values.
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enumerator BT_AUDIO_METADATA_TYPE_PROGRAM_INFO_URI = 0x07
UTF-8 encoded URI for additional Program information
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enumerator BT_AUDIO_METADATA_TYPE_AUDIO_STATE = 0x08
Audio active state.
See @ref bt_audio_active_state for valid values.
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enumerator BT_AUDIO_METADATA_TYPE_BROADCAST_IMMEDIATE = 0x09
Broadcast Audio Immediate Rendering flag
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enumerator BT_AUDIO_METADATA_TYPE_EXTENDED = 0xFE
Extended metadata
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enumerator BT_AUDIO_METADATA_TYPE_VENDOR = 0xFF
Vendor specific metadata
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enumerator BT_AUDIO_METADATA_TYPE_PREF_CONTEXT = 0x01
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enum bt_audio_location
Location values for BT Audio.
These values are defined by the Generic Audio Assigned Numbers, bluetooth.com
Values:
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enumerator BT_AUDIO_LOCATION_PROHIBITED = 0
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enumerator BT_AUDIO_LOCATION_PROHIBITED = 0
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enum bt_audio_dir
Audio Capability type.
Values:
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enumerator BT_AUDIO_DIR_SINK = 0x01
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enumerator BT_AUDIO_DIR_SOURCE = 0x02
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enumerator BT_AUDIO_DIR_SINK = 0x01
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struct bt_codec_data
- #include <audio.h>
Codec configuration structure.
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struct bt_codec
- #include <audio.h>
Codec structure.
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struct bt_codec_qos
- #include <audio.h>
Codec QoS structure.
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struct bt_codec_qos_pref
- #include <audio.h>
Audio Stream Quality of Service Preference structure.
Public Members
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bool unframed_supported
Unframed PDUs supported.
Unlike the other fields, this is not a preference but whether the codec supports unframed ISOAL PDUs.
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uint8_t phy
Preferred PHY
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uint8_t rtn
Preferred Retransmission Number
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uint16_t latency
Preferred Transport Latency
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uint32_t pd_min
Minimum Presentation Delay in microseconds.
Unlike the other fields, this is not a preference but a minimum requirement.
Value range 0 to BT_AUDIO_PD_MAX, or BT_AUDIO_PD_PREF_NONE to indicate no preference.
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uint32_t pd_max
Maximum Presentation Delay.
Unlike the other fields, this is not a preference but a maximum requirement.
Value range 0 to BT_AUDIO_PD_MAX, or BT_AUDIO_PD_PREF_NONE to indicate no preference.
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uint32_t pref_pd_min
Preferred minimum Presentation Delay.
Value range 0 to BT_AUDIO_PD_MAX.
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uint32_t pref_pd_max
Preferred maximum Presentation Delay.
Value range 0 to BT_AUDIO_PD_MAX.
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bool unframed_supported
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BT_AUDIO_BROADCAST_ID_SIZE
- group bt_audio_codec_cfg
Audio codec Config APIs.
Functions to parse codec config data when formatted as LTV wrapped into bt_codec.
Enums
-
enum bt_audio_codec_parse_err
Codec parser error codes for Codec config parsing APIs.
Values:
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enumerator BT_AUDIO_CODEC_PARSE_ERR_SUCCESS = 0
The requested type is not present in the data set.
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enumerator BT_AUDIO_CODEC_PARSE_ERR_TYPE_NOT_FOUND = -1
The requested type is not present in the data set.
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enumerator BT_AUDIO_CODEC_PARSE_ERR_INVALID_VALUE_FOUND = -2
The value found is invalid.
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enumerator BT_AUDIO_CODEC_PARSE_ERR_INVALID_PARAM = -3
The parameters specified to the function call are not valid.
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enumerator BT_AUDIO_CODEC_PARSE_ERR_SUCCESS = 0
Functions
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int bt_codec_cfg_get_freq(const struct bt_codec *codec)
Extract the frequency from a codec configuration.
- Parameters:
codec – The codec configuration to extract data from.
- Returns:
The frequency in Hz if found else a negative value of type bt_audio_codec_parse_err.
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int bt_codec_cfg_get_frame_duration_us(const struct bt_codec *codec)
Extract frame duration from BT codec config.
- Parameters:
codec – The codec configuration to extract data from.
- Returns:
Frame duration in microseconds if value is found else a negative value of type bt_audio_codec_parse_err.
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int bt_codec_cfg_get_chan_allocation_val(const struct bt_codec *codec, uint32_t *chan_allocation)
Extract channel allocation from BT codec config.
The value returned is a bit field representing one or more audio locations as specified by bt_audio_location Shall match one or more of the bits set in BT_PAC_SNK_LOC/BT_PAC_SRC_LOC.
Up to the configured BT_CODEC_LC3_CHAN_COUNT number of channels can be present.
- Parameters:
codec – The codec configuration to extract data from.
chan_allocation – Pointer to the variable to store the extracted value in.
- Returns:
BT_AUDIO_CODEC_PARSE_SUCCESS if value is found and stored in the pointer provided else a negative value of type bt_audio_codec_parse_err.
-
int bt_codec_cfg_get_octets_per_frame(const struct bt_codec *codec)
Extract frame size in octets from BT codec config.
The overall SDU size will be octets_per_frame * blocks_per_sdu.
The Bluetooth specificationa are not clear about this value - it does not state that the codec shall use this SDU size only. A codec like LC3 supports variable bit-rate (per SDU) hence it might be allowed for an encoder to reduce the frame size below this value. Hence it is recommended to use the received SDU size and divide by blocks_per_sdu rather than relying on this octets_per_sdu value to be fixed.
- Parameters:
codec – The codec configuration to extract data from.
- Returns:
Frame length in octets if value is found else a negative value of type bt_audio_codec_parse_err.
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int bt_codec_cfg_get_frame_blocks_per_sdu(const struct bt_codec *codec, bool fallback_to_default)
Extract number of audio frame blockss in each SDU from BT codec config.
The overall SDU size will be octets_per_frame * frame_blocks_per_sdu * number-of-channels.
If this value is not present a default value of 1 shall be used.
A frame block is one or more frames that represents data for the same period of time but for different channels. If the stream have two audio channels and this value is two there will be four frames in the SDU.
- Parameters:
codec – The codec configuration to extract data from.
fallback_to_default – If true this function will return the default value of 1 if the type is not found. In this case the function will only fail if a NULL pointer is provided.
- Returns:
The count of codec frames in each SDU if value is found else a negative value of type bt_audio_codec_parse_err - unless when
fallback_to_defaultis true then the value 1 is returned if frames per sdu is not found.
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bool bt_codec_get_val(const struct bt_codec *codec, uint8_t type, const struct bt_codec_data **data)
Lookup a specific value based on type.
Depending on context bt_codec will be either codec capabilities, codec configuration or meta data.
Typically types used are: bt_codec_capability_type bt_codec_config_type bt_audio_metadata_type
- Parameters:
codec – The codec data to search in.
type – The type id to look for
data – Pointer to the data-pointer to update when item is found
- Returns:
True if the type is found, false otherwise.
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enum bt_audio_codec_parse_err