UAC麦克风类特定音频流接口描述符

UAC麦克风类特定音频流接口描述符数据组织如下图：

该描述符包含了音频数据流的相关信息。

关于该描述符的字段解释详见：http://www.usbzh.com/article/detail-158.html

/* 4.5.2 Class-Specific AS Interface Descriptor */
struct uac1_as_header_descriptor {
    __u8 bLength; /* in bytes: 7 */
    __u8 bDescriptorType; /* USB_DT_CS_INTERFACE */
    __u8 bDescriptorSubtype; /* AS_GENERAL */
    __u8 bTerminalLink; /* Terminal ID of connected Terminal */
    __u8 bDelay; /* Delay introduced by the data path */
    __le16 wFormatTag; /* The Audio Data Format */
}
__attribute__((packed));#
define UAC_DT_AS_HEADER_SIZE7
static struct uac1_as_header_descriptor microphone_as_header_desc = {.bLength = UAC_DT_AS_HEADER_SIZE,
    .bDescriptorType = USB_DT_CS_INTERFACE,
    .bDescriptorSubtype = UAC_AS_GENERAL,
    .bTerminalLink = MICROPHONE_OUTPUT_TERMINAL_ID,
    .bDelay = 1,
    .wFormatTag = UAC_FORMAT_TYPE_I_PCM,
};

模拟设备信息（Free Device Monitoring Studio 抓取

• descriptors[7] = “Class-Specific Interface Descriptor”
• bLength = 7 bDescriptorType = CS_INTERFACE (36)
• bDescriptorSubtype = 1
• as_interface =
• bTerminalLink = 2
• bmControls = 1
• bFormatType = 1
• bmFormats = 35916544
• bNrChannels = 1
• bmChannelConfig = 17826305
• iChannelNames = 128