DIY - ESP32：ESP32 藍牙（Bluetooth）A2DP API 函數（七十三）

DIY - ESP32：ESP32 藍牙（Bluetooth）A2DP API 函數（七十三）：

在 ESP32 藍牙（Bluetooth）的內置了 A2DP（藍牙立體聲音訊傳輸規範 / Advanced Audio Distribution Profile）的 API 函數，只要連接雙方支援 A2DP 協定都能以 16 bits，44.1 kHz 的質素傳輸聲音訊號。

功能 - esp_a2d_register_callback

原型：esp_err_t esp_a2d_register_callback(esp_a2d_cb_t callback)

參數：callback: 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

說明：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.

範例：esp_a2d_register_callback(&bt_app_a2d_cb);

功能 - esp_a2d_sink_register_data_callback

原型：esp_err_t esp_a2d_sink_register_data_callback(esp_a2d_sink_data_cb_t callback)

參數：callback: 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

說明：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.

範例：esp_a2d_sink_register_data_callback(bt_app_a2d_data_cb);

功能 - esp_a2d_sink_init

原型：esp_err_t esp_a2d_sink_init(void)

參數：

返回：ESP_OK: if the initialization request is sent successfully

            ESP_INVALID_STATE: if bluetooth stack is not yet enabled

            ESP_FAIL: others

說明：Initialize the bluetooth A2DP sink module. This function should be called after esp_bluedroid_enable() completes successfully.

範例：esp_a2d_sink_init();

功能 - esp_a2d_sink_deinit

原型：esp_err_t esp_a2d_sink_deinit(void)

參數：

返回：ESP_OK: success

            ESP_INVALID_STATE: if bluetooth stack is not yet enabled

            ESP_FAIL: others

說明：De-initialize for A2DP sink module. This function should be called only after esp_bluedroid_enable() completes successfully.

範例：esp_a2d_sink_deinit()

功能 - esp_a2d_sink_connect

原型：esp_err_t esp_a2d_sink_connect(esp_bd_addr_t remote_bda)

參數：remote_bda: remote bluetooth device address

返回：ESP_OK: connect request is sent to lower layer

            ESP_INVALID_STATE: if bluetooth stack is not yet enabled

            ESP_FAIL: others

說明：Connect to remote bluetooth A2DP source device, must after esp_a2d_sink_init()

範例：

功能 - esp_a2d_sink_disconnect

原型：esp_err_t esp_a2d_sink_disconnect(esp_bd_addr_t remote_bda)

參數：remote_bda: 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

說明：Disconnect from the remote A2DP source device.

範例：

功能 - esp_a2d_media_ctrl

原型：esp_err_t esp_a2d_media_ctrl(esp_a2d_media_ctrl_t ctrl)

參數：ctrl: control commands for A2DP data channel

返回：ESP_OK: control command is sent to lower layer

            ESP_INVALID_STATE: if bluetooth stack is not yet enabled

            ESP_FAIL: others

說明：media control commands; this API can be used for both A2DP sink and source

範例：esp_a2d_media_ctrl(ESP_A2D_MEDIA_CTRL_CHECK_SRC_RDY);

            esp_a2d_media_ctrl(ESP_A2D_MEDIA_CTRL_START);

            esp_a2d_media_ctrl(ESP_A2D_MEDIA_CTRL_STOP);

功能 - esp_a2d_source_init

原型：esp_err_t esp_a2d_source_init(void)

參數：

返回：ESP_OK: if the initialization request is sent successfully

            ESP_INVALID_STATE: if bluetooth stack is not yet enabled

            ESP_FAIL: others

說明：Initialize the bluetooth A2DP source module. This function should be called after esp_bluedroid_enable() completes successfully.

範例：esp_a2d_source_init();

功能 - esp_a2d_source_deinit

原型：esp_err_t esp_a2d_source_deinit(void)

參數：

返回：ESP_OK: success

            ESP_INVALID_STATE: if bluetooth stack is not yet enabled

            ESP_FAIL: others

說明：De-initialize for A2DP source module. This function should be called only after esp_bluedroid_enable() completes successfully.

範例：esp_a2d_source_deinit();

功能 - esp_a2d_source_register_data_callback

原型：esp_err_t esp_a2d_source_register_data_callback(esp_a2d_source_data_cb_t callback

參數：callback: 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

說明：Register A2DP source data input function; For now the input is 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.

範例：esp_a2d_source_register_data_callback(bt_app_a2d_data_cb);

功能 - esp_a2d_source_connect

原型：esp_err_t esp_a2d_source_connect(esp_bd_addr_t remote_bda)

參數：remote_bda: remote bluetooth device address

返回：ESP_OK: connect request is sent to lower layer

            ESP_INVALID_STATE: if bluetooth stack is not yet enabled

            ESP_FAIL: others

說明：Connect to remote A2DP sink device, must after esp_a2d_source_init()

範例：static esp_bd_addr_t s_peer_bda = {0};

            esp_a2d_source_connect(s_peer_bda);

功能 - esp_a2d_source_disconnect

原型：esp_err_t esp_a2d_source_disconnect(esp_bd_addr_t remote_bda)

參數：remote_bda: 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

說明：Disconnect from the remote A2DP sink device.

範例：static esp_bd_addr_t s_peer_bda = {0};

            esp_a2d_source_disconnect(s_peer_bda);

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

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