LE Audio Manager

This document aims to guide developers on how to use the LE audio manager.

The chapter LE Audio Manager Introduction describes the LE audio library.
The chapter LE Audio Manager Initialization describes how to initialize the LE audio library.
The chapter LE Audio Samples describes the LE audio samples based on the LE audio library.

LE Audio Manager Introduction

The functions of the LE audio manager are provided by the LE audio library. The library directory and header files directory are shown as follows.

LE Audio Library and Header Files Directory
IC Type	Library Directory	Header Files Directory
RTL87x3E	`bin\rtl87x3e\leaudio`	`inc\bluetooth\leaudio`
RTL87x3D	`bin\rtl87x3d\leaudio`
RTL87x3EP	`bin\rtl87x3ep\leaudio`

If APP wants to use the LE audio manager, the leaudio.lib shall be included in the project as shown in the following figure.

../../../_images/bt_le_audio_lib_sample.png

LE Audio Manager Initialization

ble_audio_init() is used to initialize the LE audio library.

The initialization sample code is shown below:

void app_lea_profile_init(void)
{
   gatt_svc_init(GATT_SVC_USE_EXT_SERVER, MAX_BLE_SRV_NUM);
   T_BLE_AUDIO_PARAMS ble_audio_param = {0};

   ble_audio_param.evt_queue_handle = app_evt_queue_handle;
   ble_audio_param.io_queue_handle = app_io_queue_handle;
   ble_audio_param.bt_gatt_client_init = (GATT_CLIENT_DISCOV_MODE_REG_SVC_BIT |
                                          GATT_CLIENT_DISCOV_MODE_CCCD_STORAGE_BIT |
                                          GATT_CLIENT_DISCOV_MODE_USE_EXT_CLIENT);
   ble_audio_param.acl_link_num = APP_MAX_BLE_LINK_NUM;
   ble_audio_param.io_event_type = IO_MSG_TYPE_LE_AUDIO;
   ble_audio_init(&ble_audio_param);
   app_lea_acc_vc_mic_init();
   app_lea_acc_bap_init();
   app_lea_cap_init();
   app_lea_audio_data_init();
}

ble_audio_handle_gap_msg() and ble_audio_handle_gap_cb() are used to handle message.

GAP message and callback handling functions are shown below:

void app_handle_gap_msg(T_IO_MSG *p_gap_msg)
{
   T_LE_GAP_MSG gap_msg;
   uint8_t conn_id;

   memcpy(&gap_msg, &p_gap_msg->u.param, sizeof(p_gap_msg->u.param));
   ......
   ble_audio_handle_gap_msg(p_gap_msg->subtype, gap_msg);
}

T_APP_RESULT app_gap_callback(uint8_t cb_type, void *p_cb_data)
{
   T_APP_RESULT result = APP_RESULT_SUCCESS;
   T_LE_CB_DATA *p_data = (T_LE_CB_DATA *)p_cb_data;

   ble_audio_handle_gap_cb(cb_type, p_cb_data);
   ......
}

ble_audio_handle_gap_msg() is used to handle GAP messages. ble_audio_handle_gap_cb() is used to handle GAP callback messages.

ble_audio_handle_msg() is used to handle IO_MSG_TYPE_LE_AUDIO messages.

IO message handling function is shown below:

void app_handle_io_msg(T_IO_MSG io_msg)
{
   uint16_t msg_type = io_msg.type;
   uint8_t rx_char;

   switch (msg_type)
   {
   case IO_MSG_TYPE_LE_AUDIO:
      {
         ble_audio_handle_msg(&io_msg);
      }
      break;
   ......
   default:
      break;
   }
}

ble_audio_cback_register() is used to register LE audio callback function.

LE audio callback handling sample is shown below:

uint16_t app_lea_ini_cap_handle_msg(T_LE_AUDIO_MSG msg, void *buf)
{
   uint16_t cb_result = BLE_AUDIO_CB_RESULT_SUCCESS;
   T_APP_LE_LINK *p_link = NULL;

   switch (msg)
   {
   case LE_AUDIO_MSG_CAP_DIS_DONE:
      {
         ......
      }
      break;

   default:
      break;
   }
   return cb_result;
}

void app_lea_ini_cap_init(void)
{
   ......
   ble_audio_cback_register(app_lea_ini_cap_handle_msg);
}

LE Audio Samples

CAP defines the roles of the Acceptor, Initiator, and Commander. SDK provides a corresponding demo application for the developer’s reference in development.

Acceptor Role
1. Can transmit and receive unicast audio streams.
2. Can receive broadcast audio streams.
3. Can scan for broadcast audio streams.
4. Can delegate scanning for broadcast audio streams to a commander.
5. Demo application: LE Audio CAP Acceptor.
Commander Role
1. Can request acceptors to start or stop reception of broadcast audio streams transmitted by an initiator.
2. Can control the mute state and/or the volume of the audio rendered by acceptors.
3. Can control the mute state and/or signal level of a microphone on acceptors.
4. Can coordinate a set of acceptors and discover acceptors that are members of a coordinated set.
5. Demo application: LE Audio CAP Commander.
Initiator Role
1. Can transmit and receive unicast audio streams.
2. Can transmit broadcast audio streams.
3. Provides Broadcast_Codes for encrypted broadcast audio streams.
4. Can coordinate a set of acceptors and discover acceptors that are members of a coordinated set.
5. Demo application: LE Audio CAP Initiator.

Supported Components

The table below lists the supported components for each LE audio sample project. The components are separated by Macros.

Supported Components for LE Audio Sample Project
Component	Macro	GAP Role	LE Audio CAP Acceptor	LE Audio CAP Commander	LE Audio CAP Initiator
BAP Unicast Client	BAP_UNICAST_CLIENT	GAP Central			√
BAP Unicast Server	BAP_UNICAST_SERVER	GAP Peripheral	√
BAP Broadcast Source	BAP_BROADCAST_SOURCE	GAP Broadcaster			√
BAP Broadcast Sink	BAP_BROADCAST_SINK	GAP Peripheral GAP Observer	√
BAP Broadcast Assistant	BAP_BROADCAST_ASSISTANT	GAP Central GAP Observer		√	√
BAP Scan Delegator	BAP_SCAN_DELEGATOR	GAP Peripheral	√
VCP Volume Controller	VCP_VOLUME_CONTROLLER	GAP Central		√	√
VCP Volume Renderer	VCP_VOLUME_RENDERER	GAP Peripheral	√
MICP Microphone Controller	MICP_MIC_CONTROLLER	GAP Central		√	√
MICP Microphone Device	MICP_MIC_DEVICE	GAP Peripheral	√
CCP Call Control Server	CCP_CALL_CONTROL_SERVER	GAP Central			√
CCP Call Control Client	CCP_CALL_CONTROL_CLIENT	GAP Peripheral	√
MCP Media Control Server	MCP_MEDIA_CONTROL_SERVER	GAP Central			√
MCP Media Control Client	MCP_MEDIA_CONTROL_CLIENT	GAP Peripheral	√
CSIP Set Coordinator	CSIP_SET_COORDINATOR	GAP Central		√	√
CSIP Set Member	CSIP_SET_MEMBER	GAP Peripheral	√

References

[1] LE Audio Specifications