uvc control

a1 82 00 04 00 03 08 00
bmRequestType
0xa1: GET_CUR,GET_MIN,GET_MAX,GET_RES,GET_INFO,GET_DEF
bRequest:
0x82: GET_MIN
其他为:

define UVC_RC_UNDEFINED 0x00

define UVC_SET_CUR 0x01

define UVC_GET_CUR 0x81

define UVC_GET_MIN 0x82

define UVC_GET_MAX 0x83

define UVC_GET_RES 0x84

define UVC_GET_LEN 0x85

define UVC_GET_INFO 0x86

define UVC_GET_DEF 0x87

wValue:CS (Control Selector)
00 04:曝光时间控制命令。
其他为：

define CT_CONTROL_UNDEFINED 0x00

define CT_SCANNING_MODE_CONTROL 0x01

define CT_AE_MODE_CONTROL 0x02 ///

define CT_AE_PRIORITY_CONTROL 0x03

define CT_EXPOSURE_TIME_ABSOLUTE_CONTROL 0x04 //

define CT_EXPOSURE_TIME_RELATIVE_CONTROL 0x05

define CT_FOCUS_ABSOLUTE_CONTROL 0x06

define CT_FOCUS_RELATIVE_CONTROL 0x07

define CT_FOCUS_AUTO_CONTROL 0x08

define CT_IRIS_ABSOLUTE_CONTROL 0x09

define CT_IRIS_RELATIVE_CONTROL 0x0A

define CT_ZOOM_ABSOLUTE_CONTROL 0x0B

define CT_ZOOM_RELATIVE_CONTROL 0x0C

define CT_PANTILT_ABSOLUTE_CONTROL 0x0D

define CT_PANTILT_RELATIVE_CONTROL 0x0E

define CT_ROLL_ABSOLUTE_CONTROL 0x0F

define CT_ROLL_RELATIVE_CONTROL 0x10

define CT_PRIVACY_CONTROL 0x11

wIndex:
00 03：
Unit or Terminal ID and Interface ？？？单位
wLength:
08 00 ：
Length of parameter block.
8字节。4字节就是 04 00.
（

UVC_GET_CUR
Obtain the current value of the control.
UVC_GET_MIN
Obtain the minimum value of the control.
UVC_GET_MAX
Obtain the maximum value of the control.
UVC_GET_DEF
Obtain the default value of the control.
UVC_GET_RES
Query the resolution of the control, i.e. the step size of the
allowed control values.
UVC_GET_LEN
Query the size of the control in bytes.
UVC_GET_INFO
Query the control information bitmap, which indicates whether
get/set requests are supported.
UVC_SET_CUR
Update the value of the control.）