低功耗蓝牙 LE 音频配置文件详情-2.PACS 服务
PACS服务用于点对点音频，定义了设备的音频能力，其服务定义如下。
| Characteristic Name |
Requirement |
Mandatory Properties |
Optional Properties |
Security Permissions |
| Sink PAC |
C.1 |
Read |
Notify |
Encryption required |
| Sink Audio Locations |
C.2 |
Read |
Notify, Write |
Encryption required |
| Source PAC |
C.1 |
Read |
Notify |
Encryption required |
| Source Audio Locations |
C.3 |
Read |
Notify, Write |
Encryption required |
| Available Audio Contexts |
M |
Read, Notify |
None |
Encryption required |
| Supported Audio Contexts |
M |
Read |
Notify |
Encryption required |
其中，Source PAC为音频发送能力属性，当设备支持音频发送时才需要定义，其格式如下：
| Parameter |
Size (Octets) |
Description |
| Number_of_PAC_records |
1 |
Number of PAC records, [i], for this characteristic |
| Codec_ID[i] |
5 |
Octet 0: Coding_Format value of the [ith] PAC record. Coding_Format values are defined in Bluetooth Assigned Numbers. Octet 1–2: Company _ID value of the [ith] PAC record. Shall be 0x0000 if octet 0 is not 0xFF. Company_ID values are defined in Bluetooth Assigned Numbers. Octet 3–4: Vendor-specific codec_ID value of the [ith] PAC record. Shall be 0x0000 if octet 0 is not 0xFF. |
| Codec_Specific_Capabilities_Length[i] |
1 |
Length of the Codec_Specific_Capabilities value of the [ith] PAC record. Shall be 0x00 if the Codec_Specific_Capabilities value of the [ith] PAC record is empty. |
| Codec_Specific_Capabilities[i] |
Varies |
Codec_Specific_Capabilities value of the [ith] PAC record. |
| Metadata_Length[i] |
1 |
Length of the Metadata field of the [ith] PAC record. Shall be 0x00 if the Metadata value of the [ith] PAC record value is empty. |
| Metadata[i] |
Varies |
LTV-formatted Metadata applicable to the [ith] PAC record. Shall exist only if the value of the Metadata_Length field is not 0x00. |
Sink PAC为音频接收能力属性，当设备支持音频接收时才需要定义，其格式如下：
| Parameter |
Size (Octets) |
Description |
| Number_of_PAC_records |
1 |
Number of PAC records, [i], in this characteristic. |
| Codec_ID[i] |
5 |
Octet 0: Coding Format of the [ith] PAC record. Coding_Format values are defined in Bluetooth Assigned Numbers Octet 1–2: Company_ID value of the [ith] PAC record. Company_ID values are defined in Bluetooth Assigned Numbers Shall be 0x0000 if octet 0 is not 0xFF. Octet 3–4: Vendor-specific codec_ID value of the [ith] PAC record. Shall be 0x0000 if octet 0 is not 0xFF. |
| Codec_Specific_Capabilities_Length[i] |
1 |
Length, in octets, of the Codec_Specific_Capabilities value of the [ith] PAC record. Shall be 0x00 if the Codec_Specific_Capabilities value of the [ith] PAC record is empty. |
| Codec_Specific_Capabilities[i] |
Varies |
Codec_Specific_Capabilities value of the [ith] PAC record. |
| Metadata_Length[i] |
1 |
Length of the Metadata field of the [ith] PAC record. Shall be 0x00 if the Metadata value of the [ith] PAC record value is empty. |
| Metadata[i] |
Varies |
Length-type-value (LTV)-formatted Metadata applicable to the [ith] PAC record. Shall exist only if the value of the Metadata_Length field is not 0x00. |
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