Bluetooth A2DP API
Application Example
Check bluetooth/bluedroid/classic_bt folder in ESP-IDF examples, which contains the following application:
This is a A2DP sink client demo. This demo can be discovered and connected by A2DP source device and receive the audio stream from remote device - bluetooth/bluedroid/classic_bt/a2dp_sink
API Reference
Functions
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esp_err_t esp_a2d_register_callback(esp_a2d_cb_t callback)
Register application callback function to A2DP module. This function should be called only after esp_bluedroid_enable() completes successfully, used by both A2DP source and sink.
- 参数
callback – [in] A2DP event callback function
- 返回
ESP_OK: success
ESP_INVALID_STATE: if bluetooth stack is not yet enabled
ESP_FAIL: if callback is a NULL function pointer
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esp_err_t esp_a2d_sink_register_data_callback(esp_a2d_sink_data_cb_t callback)
Register A2DP sink data output function; For now the output is PCM data stream decoded from SBC format. This function should be called only after esp_bluedroid_enable() completes successfully, used only by A2DP sink. The callback is invoked in the context of A2DP sink task whose stack size is configurable through menuconfig.
- 参数
callback – [in] A2DP sink data callback function
- 返回
ESP_OK: success
ESP_INVALID_STATE: if bluetooth stack is not yet enabled
ESP_FAIL: if callback is a NULL function pointer
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esp_err_t esp_a2d_sink_init(void)
Initialize the bluetooth A2DP sink module. This function should be called after esp_bluedroid_enable() completes successfully, and ESP_A2D_PROF_STATE_EVT with ESP_A2D_INIT_SUCCESS will reported to the APP layer. Note: A2DP can work independently. If you want to use AVRC together, you should initiate AVRC first. This function should be called after esp_bluedroid_enable() completes successfully.
- 返回
ESP_OK: if the initialization request is sent successfully
ESP_INVALID_STATE: if bluetooth stack is not yet enabled
ESP_FAIL: others
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esp_err_t esp_a2d_sink_deinit(void)
De-initialize for A2DP sink module. This function should be called only after esp_bluedroid_enable() completes successfully, and ESP_A2D_PROF_STATE_EVT with ESP_A2D_DEINIT_SUCCESS will reported to APP layer.
- 返回
ESP_OK: if the deinitialization request is sent successfully
ESP_INVALID_STATE: if bluetooth stack is not yet enabled
ESP_FAIL: others
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esp_err_t esp_a2d_sink_connect(esp_bd_addr_t remote_bda)
Connect to remote bluetooth A2DP source device. This API must be called after esp_a2d_sink_init() and before esp_a2d_sink_deinit().
- 参数
remote_bda – [in] remote bluetooth device address
- 返回
ESP_OK: connect request is sent to lower layer successfully
ESP_INVALID_STATE: if bluetooth stack is not yet enabled
ESP_FAIL: others
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esp_err_t esp_a2d_sink_disconnect(esp_bd_addr_t remote_bda)
Disconnect from the remote A2DP source device. This API must be called after esp_a2d_sink_init() and before esp_a2d_sink_deinit().
- 参数
remote_bda – [in] remote bluetooth device address
- 返回
ESP_OK: disconnect request is sent to lower layer successfully
ESP_INVALID_STATE: if bluetooth stack is not yet enabled
ESP_FAIL: others
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esp_err_t esp_a2d_media_ctrl(esp_a2d_media_ctrl_t ctrl)
Media control commands. This API can be used for both A2DP sink and source and must be called after esp_a2d_sink_init() and before esp_a2d_sink_deinit().
- 参数
ctrl – [in] control commands for A2DP data channel
- 返回
ESP_OK: control command is sent to lower layer successfully
ESP_INVALID_STATE: if bluetooth stack is not yet enabled
ESP_FAIL: others
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esp_err_t esp_a2d_source_init(void)
Initialize the bluetooth A2DP source module. A2DP can work independently. If you want to use AVRC together, you should initiate AVRC first. This function should be called after esp_bluedroid_enable() completes successfully, and ESP_A2D_PROF_STATE_EVT with ESP_A2D_INIT_SUCCESS will reported to the APP layer. Note: A2DP can work independently. If you want to use AVRC together, you should initiate AVRC first.
- 返回
ESP_OK: if the initialization request is sent to lower layer successfully
ESP_INVALID_STATE: if bluetooth stack is not yet enabled
ESP_FAIL: others
-
esp_err_t esp_a2d_source_deinit(void)
De-initialize for A2DP source module. This function should be called only after esp_bluedroid_enable() completes successfully, and ESP_A2D_PROF_STATE_EVT with ESP_A2D_DEINIT_SUCCESS will reported to APP layer.
- 返回
ESP_OK: success
ESP_INVALID_STATE: if bluetooth stack is not yet enabled
ESP_FAIL: others
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esp_err_t esp_a2d_source_register_data_callback(esp_a2d_source_data_cb_t callback)
Register A2DP source data input function. For now, the input shoule be PCM data stream. This function should be called only after esp_bluedroid_enable() completes successfully. The callback is invoked in the context of A2DP source task whose stack size is configurable through menuconfig.
- 参数
callback – [in] A2DP source data callback function
- 返回
ESP_OK: success
ESP_INVALID_STATE: if bluetooth stack is not yet enabled
ESP_FAIL: if callback is a NULL function pointer
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esp_err_t esp_a2d_source_connect(esp_bd_addr_t remote_bda)
Connect to remote A2DP sink device. This API must be called after esp_a2d_source_init() and before esp_a2d_source_deinit().
- 参数
remote_bda – [in] remote bluetooth device address
- 返回
ESP_OK: connect request is sent to lower layer successfully
ESP_INVALID_STATE: if bluetooth stack is not yet enabled
ESP_FAIL: others
-
esp_err_t esp_a2d_source_disconnect(esp_bd_addr_t remote_bda)
Disconnect from the remote A2DP sink device. This API must be called after esp_a2d_source_init() and before esp_a2d_source_deinit().
- 参数
remote_bda – [in] remote bluetooth device address
- 返回
ESP_OK: disconnect request is sent to lower layer
ESP_INVALID_STATE: if bluetooth stack is not yet enabled
ESP_FAIL: others
Unions
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union esp_a2d_cb_param_t
- #include <esp_a2dp_api.h>
A2DP state callback parameters.
Public Members
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struct esp_a2d_cb_param_t::a2d_conn_stat_param conn_stat
A2DP connection status
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struct esp_a2d_cb_param_t::a2d_audio_stat_param audio_stat
audio stream playing state
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struct esp_a2d_cb_param_t::a2d_audio_cfg_param audio_cfg
media codec configuration information
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struct esp_a2d_cb_param_t::media_ctrl_stat_param media_ctrl_stat
status in acknowledgement to media control commands
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struct esp_a2d_cb_param_t::a2d_prof_stat_param a2d_prof_stat
status to indicate a2d prof init or deinit
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struct a2d_audio_cfg_param
- #include <esp_a2dp_api.h>
ESP_A2D_AUDIO_CFG_EVT.
Public Members
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esp_bd_addr_t remote_bda
remote bluetooth device address
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esp_a2d_mcc_t mcc
A2DP media codec capability information
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esp_bd_addr_t remote_bda
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struct a2d_audio_stat_param
- #include <esp_a2dp_api.h>
ESP_A2D_AUDIO_STATE_EVT.
Public Members
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esp_a2d_audio_state_t state
one of the values from esp_a2d_audio_state_t
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esp_bd_addr_t remote_bda
remote bluetooth device address
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esp_a2d_audio_state_t state
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struct a2d_conn_stat_param
- #include <esp_a2dp_api.h>
ESP_A2D_CONNECTION_STATE_EVT.
Public Members
-
esp_a2d_connection_state_t state
one of values from esp_a2d_connection_state_t
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esp_bd_addr_t remote_bda
remote bluetooth device address
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esp_a2d_disc_rsn_t disc_rsn
reason of disconnection for “DISCONNECTED”
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esp_a2d_connection_state_t state
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struct a2d_prof_stat_param
- #include <esp_a2dp_api.h>
ESP_A2D_PROF_STATE_EVT.
Public Members
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esp_a2d_init_state_t init_state
a2dp profile state param
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esp_a2d_init_state_t init_state
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struct media_ctrl_stat_param
- #include <esp_a2dp_api.h>
ESP_A2D_MEDIA_CTRL_ACK_EVT.
Public Members
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esp_a2d_media_ctrl_t cmd
media control commands to acknowledge
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esp_a2d_media_ctrl_ack_t status
acknowledgement to media control commands
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esp_a2d_media_ctrl_t cmd
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struct esp_a2d_cb_param_t::a2d_conn_stat_param conn_stat
Structures
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struct esp_a2d_mcc_t
A2DP media codec capabilities union
Public Members
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esp_a2d_mct_t type
A2DP media codec type
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uint8_t sbc[(4)]
SBC codec capabilities
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uint8_t m12[(4)]
MPEG-1,2 audio codec capabilities
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uint8_t m24[(6)]
MPEG-2, 4 AAC audio codec capabilities
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uint8_t atrac[(7)]
ATRAC family codec capabilities
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union esp_a2d_mcc_t::[anonymous] cie
A2DP codec information element
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esp_a2d_mct_t type
Macros
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ESP_A2D_MCT_SBC
Media codec types supported by A2DP.
SBC
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ESP_A2D_MCT_M12
MPEG-1, 2 Audio
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ESP_A2D_MCT_M24
MPEG-2, 4 AAC
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ESP_A2D_MCT_ATRAC
ATRAC family
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ESP_A2D_MCT_NON_A2DP
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ESP_A2D_CIE_LEN_SBC
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ESP_A2D_CIE_LEN_M12
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ESP_A2D_CIE_LEN_M24
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ESP_A2D_CIE_LEN_ATRAC
Type Definitions
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typedef uint8_t esp_a2d_mct_t
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typedef void (*esp_a2d_cb_t)(esp_a2d_cb_event_t event, esp_a2d_cb_param_t *param)
A2DP profile callback function type.
- Param event
: Event type
- Param param
: Pointer to callback parameter
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typedef void (*esp_a2d_sink_data_cb_t)(const uint8_t *buf, uint32_t len)
A2DP sink data callback function.
- Param buf
[in] : pointer to the data received from A2DP source device and is PCM format decoded from SBC decoder; buf references to a static memory block and can be overwritten by upcoming data
- Param len
[in] : size(in bytes) in buf
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typedef int32_t (*esp_a2d_source_data_cb_t)(uint8_t *buf, int32_t len)
A2DP source data read callback function.
- Param buf
[in] : buffer to be filled with PCM data stream from higher layer
- Param len
[in] : size(in bytes) of data block to be copied to buf. -1 is an indication to user that data buffer shall be flushed
- Return
size of bytes read successfully, if the argument len is -1, this value is ignored.
Enumerations
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enum esp_a2d_connection_state_t
Bluetooth A2DP connection states.
Values:
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enumerator ESP_A2D_CONNECTION_STATE_DISCONNECTED
connection released
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enumerator ESP_A2D_CONNECTION_STATE_CONNECTING
connecting remote device
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enumerator ESP_A2D_CONNECTION_STATE_CONNECTED
connection established
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enumerator ESP_A2D_CONNECTION_STATE_DISCONNECTING
disconnecting remote device
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enumerator ESP_A2D_CONNECTION_STATE_DISCONNECTED
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enum esp_a2d_disc_rsn_t
Bluetooth A2DP disconnection reason.
Values:
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enumerator ESP_A2D_DISC_RSN_NORMAL
Finished disconnection that is initiated by local or remote device
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enumerator ESP_A2D_DISC_RSN_ABNORMAL
Abnormal disconnection caused by signal loss
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enumerator ESP_A2D_DISC_RSN_NORMAL
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enum esp_a2d_audio_state_t
Bluetooth A2DP datapath states.
Values:
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enumerator ESP_A2D_AUDIO_STATE_REMOTE_SUSPEND
audio stream datapath suspended by remote device
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enumerator ESP_A2D_AUDIO_STATE_STOPPED
audio stream datapath stopped
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enumerator ESP_A2D_AUDIO_STATE_STARTED
audio stream datapath started
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enumerator ESP_A2D_AUDIO_STATE_REMOTE_SUSPEND
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enum esp_a2d_media_ctrl_ack_t
A2DP media control command acknowledgement code.
Values:
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enumerator ESP_A2D_MEDIA_CTRL_ACK_SUCCESS
media control command is acknowledged with success
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enumerator ESP_A2D_MEDIA_CTRL_ACK_FAILURE
media control command is acknowledged with failure
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enumerator ESP_A2D_MEDIA_CTRL_ACK_BUSY
media control command is rejected, as previous command is not yet acknowledged
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enumerator ESP_A2D_MEDIA_CTRL_ACK_SUCCESS
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enum esp_a2d_media_ctrl_t
A2DP media control commands.
Values:
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enumerator ESP_A2D_MEDIA_CTRL_NONE
Not for application use, use inside stack only.
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enumerator ESP_A2D_MEDIA_CTRL_CHECK_SRC_RDY
check whether AVDTP is connected, only used in A2DP source
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enumerator ESP_A2D_MEDIA_CTRL_START
command to set up media transmission channel
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enumerator ESP_A2D_MEDIA_CTRL_STOP
command to stop media transmission
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enumerator ESP_A2D_MEDIA_CTRL_SUSPEND
command to suspend media transmission
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enumerator ESP_A2D_MEDIA_CTRL_NONE
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enum esp_a2d_init_state_t
Bluetooth A2DP Initiation states.
Values:
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enumerator ESP_A2D_DEINIT_SUCCESS
A2DP profile deinit successful event
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enumerator ESP_A2D_INIT_SUCCESS
A2DP profile deinit successful event
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enumerator ESP_A2D_DEINIT_SUCCESS
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enum esp_a2d_cb_event_t
A2DP callback events.
Values:
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enumerator ESP_A2D_CONNECTION_STATE_EVT
connection state changed event
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enumerator ESP_A2D_AUDIO_STATE_EVT
audio stream transmission state changed event
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enumerator ESP_A2D_AUDIO_CFG_EVT
audio codec is configured, only used for A2DP SINK
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enumerator ESP_A2D_MEDIA_CTRL_ACK_EVT
acknowledge event in response to media control commands
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enumerator ESP_A2D_PROF_STATE_EVT
indicate a2dp init&deinit complete
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enumerator ESP_A2D_CONNECTION_STATE_EVT