DIY - ESP32：ESP32 藍牙（Bluetooth）A2DP API 函數結構件及其它（七十四）

DIY - ESP32：ESP32 藍牙（Bluetooth）A2DP API 函數結構件及其它（七十四）：

除了 ESP32 藍牙（Bluetooth）的 A2DP（Main API）的 API 函數模塊外，還有泛型型別定義（Type Definitions）和枚舉（Enumerations）。

1. Structure：

1.1. struct esp_a2d_mcc_t：

A2DP media codec capabilities union.

Public Members	Description
esp_a2d_mct_t type	A2DP media codec type
union esp_a2d_mcc_t::@1 esp_a2d_mcc_t::cie	A2DP codec information element

2. Macros：

ESP_A2D_MCT_SBC：

Media codec types supported by A2DP.

Macros	Description
ESP_A2D_MCT_M12	MPEG-1, 2 Audio
ESP_A2D_MCT_M24	MPEG-2, 4 AAC
ESP_A2D_MCT_ATRAC	ATRAC family
ESP_A2D_MCT_NON_A2DP
ESP_A2D_CIE_LEN_SBC
ESP_A2D_CIE_LEN_M12
ESP_A2D_CIE_LEN_M24
ESP_A2D_CIE_LEN_ATRAC

3. Type Definitions：

Type Definitions	Description
typedef uint8_t esp_a2d_mct_t
typedef void (*esp_a2d_cb_t)(esp_a2d_cb_event_t event, esp_a2d_cb_param_t *para	A2DP profile callback function type. Parameters event: : Event type param: : Pointer to callback parameter
typedef void (*esp_a2d_sink_data_cb_t)(const uint8_t *buf, uint32_t len)	A2DP profile data callback function. Parameters buf: : data received from A2DP source device and is PCM format decoder from SBC decoder; buf references to a static memory block and can be overwritten by upcoming data len: : size(in bytes) in buf
typedef int32_t (*esp_a2d_source_data_cb_t)(uint8_t *buf, int32_t len)	A2DP source data read callback function. Return size of bytes read successfully, if the argument len is -1, this value is ignored. Parameters buf: : buffer to be filled with PCM data stream from higher layer len: : size(in bytes) of data block to be copied to buf. -1 is an indication to user that data buffer shall be flushed

4. Enumerations：

4.1. enum esp_a2d_connection_state_t：

Bluetooth A2DP connection states.

Enumeration	Description
ESP_A2D_CONNECTION_STATE_DISCONNECTED = 0	connection released
ESP_A2D_CONNECTION_STATE_CONNECTING	connecting remote device
ESP_A2D_CONNECTION_STATE_CONNECTED	connection established
ESP_A2D_CONNECTION_STATE_DISCONNECTING	disconnecting remote device

4.2. enum esp_a2d_disc_rsn_t：

Bluetooth A2DP disconnection reason.

Enumeration	Description
ESP_A2D_DISC_RSN_NORMAL = 0	Finished disconnection that is initiated by local or remote device
ESP_A2D_DISC_RSN_ABNORMAL	Abnormal disconnection caused by signal loss

4.3. enum esp_a2d_audio_state_t：

Bluetooth A2DP datapath states.

Enumeration	Description
ESP_A2D_AUDIO_STATE_REMOTE_SUSPEND = 0	audio stream datapath suspended by remote device
ESP_A2D_AUDIO_STATE_STOPPED	audio stream datapath stopped
ESP_A2D_AUDIO_STATE_STARTED	audio stream datapath started

4.4. enum esp_a2d_media_ctrl_ack_t：

A2DP media control command acknowledgement code.

Enumeration	Description
ESP_A2D_MEDIA_CTRL_ACK_SUCCESS = 0	media control command is acknowledged with success
ESP_A2D_MEDIA_CTRL_ACK_FAILURE	media control command is acknowledged with failure
ESP_A2D_MEDIA_CTRL_ACK_BUSY	media control command is rejected, as previous command is not yet acknowledged

4.5. enum esp_a2d_media_ctrl_t：

A2DP media control commands.

Enumeration	Description
ESP_A2D_MEDIA_CTRL_NONE = 0	dummy command
ESP_A2D_MEDIA_CTRL_CHECK_SRC_RDY	check whether AVDTP is connected, only used in A2DP source
ESP_A2D_MEDIA_CTRL_START	command to set up media transmission channel
ESP_A2D_MEDIA_CTRL_STOP	command to stop media transmission
ESP_A2D_MEDIA_CTRL_SUSPEND	command to suspend media transmission

4.6. enum esp_a2d_cb_event_t：

A2DP callback events.

Enumeration	Description
ESP_A2D_CONNECTION_STATE_EVT = 0	connection state changed event
ESP_A2D_AUDIO_STATE_EVT	audio stream transmission state changed event
ESP_A2D_AUDIO_CFG_EVT	audio codec is configured, only used for A2DP SINK
ESP_A2D_MEDIA_CTRL_ACK_EVT	acknowledge event in response to media control commands

5. Unions：

union esp_a2d_cb_param_t.

#include

A2DP state callback parameters.

Unions	Description
struct esp_a2d_cb_param_t::a2d_conn_stat_param conn_stat	A2DP connection status
struct esp_a2d_cb_param_t::a2d_audio_stat_param audio_stat	audio stream playing state
struct esp_a2d_cb_param_t::a2d_audio_cfg_param audio_cfg	media codec configuration information
struct esp_a2d_cb_param_t::media_ctrl_stat_param media_ctrl_stat	status in acknowledgement to media control commands
struct a2d_audio_cfg_param	#include ESP_A2D_AUDIO_CFG_EVT. Public Members esp_bd_addr_t remote_bda - remote bluetooth device address esp_a2d_mcc_t mcc - A2DP media codec capability information
struct a2d_audio_stat_param	#include ESP_A2D_AUDIO_STATE_EVT. Public Members esp_a2d_audio_state_t state - one of the values from esp_a2d_audio_state_t esp_bd_addr_t remote_bda - remote bluetooth device address
struct a2d_conn_stat_param	#include ESP_A2D_CONNECTION_STATE_EVT Public Members esp_a2d_connection_state_t state - one of values from esp_a2d_connection_state_t esp_bd_addr_t remote_bda - remote bluetooth device address esp_a2d_disc_rsn_t disc_rsn - reason of disconnection for “DISCONNECTED”
struct media_ctrl_stat_param	#include ESP_A2D_MEDIA_CTRL_ACK_EVT. Public Members esp_a2d_media_ctrl_t cmd - media control commands to acknowledge esp_a2d_media_ctrl_ack_t status -   acknowledgement to media control commands

Header File： bt/bluedroid/api/include/api/esp_a2dp_api.h
參考網址：https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/bluetooth/esp_a2dp.html

2019年 1月 18日 天氣報告

氣溫：18.2度 @ 19:30

相對濕度：百分之 80%

天氣：多雲