Win10下基于WDF实现虚拟USB摄像头

背景
如果只是想实现简单的摄像头功能,其实没必要虚拟USB,可以考虑DirectShow 、AVstream等方案
项目要求将网络NDI摄像头传输的音视频数据传给zoom(zoom.us)来使用,同时要求通过zoom来控制摄像头(PTZ),据了解zoom只能控制UVC(USB video camera)摄像头,所以只能选择虚拟USB摄像头
开工之前也在网上找了许多参考,比较靠谱的
1.https://blog.csdn.net/fanxius...
这位大神还有其它实现摄像头的文章供参考
2.https://github.com/cezanne/us...

UDE 及 USB基础知识
这里介绍的是基于微软UDE框架的实现
如果你也想实现类似的功能,建议先熟悉下下面的内容,避免走弯路
https://docs.microsoft.com/en...

https://www.spinelelectronics...

https://docs.microsoft.com/en...

https://github.com/microsoft/...

下面介绍下实现虚拟UVC摄像头需要关注的几个技术点
(未完待续)

1. 设备描述符

具体可以参考UVC文档的3.1节
image.png
基本上我们只需要关心device descriptor和configuration descriptor
下面是Logitech Webcam C170 的描述符信息供参考
`


Bus 001 Device 006: ID 046d:082b Logitech, Inc. Webcam C170
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  idVendor           0x046d Logitech, Inc.
  idProduct          0x082b Webcam C170
  bcdDevice           28.26
  iManufacturer           1 
  iProduct                2 
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x046c
    bNumInterfaces          4
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0x80
      (Bus Powered)
    MaxPower              500mA
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         0
      bInterfaceCount         2
      bFunctionClass         14 Video
      bFunctionSubClass       3 Video Interface Collection
      bFunctionProtocol       0 
      iFunction               4 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      1 Video Control
      bInterfaceProtocol      0 
      iInterface              4 
      VideoControl Interface Descriptor:
        bLength                13
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdUVC               1.00
        wTotalLength       0x004f
        dwClockFrequency       30.000000MHz
        bInCollection           1
        baInterfaceNr( 0)       1
      VideoControl Interface Descriptor:
        bLength                28
        bDescriptorType        36
        bDescriptorSubtype      6 (EXTENSION_UNIT)
        bUnitID                 6
        guidExtensionCode         {68bbd0b0-61a4-4b83-90b7-a6215f3c4f70}
        bNumControl            24
        bNrPins                 1
        baSourceID( 0)          2
        bControlSize            3
        bmControls( 0)       0xff
        bmControls( 1)       0xff
        bmControls( 2)       0xff
        iExtension              0 
      VideoControl Interface Descriptor:
        bLength                18
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             1
        wTerminalType      0x0201 Camera Sensor
        bAssocTerminal          0
        iTerminal               0 
        wObjectiveFocalLengthMin      0
        wObjectiveFocalLengthMax      0
        wOcularFocalLength            0
        bControlSize                  3
        bmControls           0x00000a0e
          Auto-Exposure Mode
          Auto-Exposure Priority
          Exposure Time (Absolute)
          Zoom (Absolute)
          PanTilt (Absolute)
      VideoControl Interface Descriptor:
        bLength                11
        bDescriptorType        36
        bDescriptorSubtype      5 (PROCESSING_UNIT)
      Warning: Descriptor too short
        bUnitID                 2
        bSourceID               1
        wMaxMultiplier          0
        bControlSize            2
        bmControls     0x0000157f
          Brightness
          Contrast
          Hue
          Saturation
          Sharpness
          Gamma
          White Balance Temperature
          Backlight Compensation
          Power Line Frequency
          White Balance Temperature, Auto
        iProcessing             0 
        bmVideoStandards     0x09
          None
          SECAM - 625/50
      VideoControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             3
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bSourceID               2
        iTerminal               0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0010  1x 16 bytes
        bInterval               7
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              4 
      VideoStreaming Interface Descriptor:
        bLength                            15
        bDescriptorType                    36
        bDescriptorSubtype                  1 (INPUT_HEADER)
        bNumFormats                         2
        wTotalLength                   0x02e9
        bEndPointAddress                  130
        bmInfo                              0
        bTerminalLink                       3
        bStillCaptureMethod                 1
        bTriggerSupport                     1
        bTriggerUsage                       0
        bControlSize                        1
        bmaControls( 0)                     0
        bmaControls( 1)                     0
      VideoStreaming Interface Descriptor:
        bLength                            27
        bDescriptorType                    36
        bDescriptorSubtype                  4 (FORMAT_UNCOMPRESSED)
        bFormatIndex                        1
        bNumFrameDescriptors                9
        guidFormat                            {32595559-0000-0010-8000-00aa00389b71}
        bBitsPerPixel                      16
        bDefaultFrameIndex                  1
        bAspectRatioX                       0
        bAspectRatioY                       0
        bmInterlaceFlags                 0x00
          Interlaced stream or variable: No
          Fields per frame: 2 fields
          Field 1 first: No
          Field pattern: Field 1 only
        bCopyProtect                        0
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         1
        bmCapabilities                   0x01
          Still image supported
        wWidth                            640
        wHeight                           480
        dwMinBitRate                 73728000
        dwMaxBitRate                147456000
        dwMaxVideoFrameBufferSize      614400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         2
        bmCapabilities                   0x01
          Still image supported
        wWidth                            352
        wHeight                           288
        dwMinBitRate                 24330240
        dwMaxBitRate                 48660480
        dwMaxVideoFrameBufferSize      202752
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         3
        bmCapabilities                   0x01
          Still image supported
        wWidth                            320
        wHeight                           240
        dwMinBitRate                 18432000
        dwMaxBitRate                 36864000
        dwMaxVideoFrameBufferSize      153600
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         4
        bmCapabilities                   0x01
          Still image supported
        wWidth                            176
        wHeight                           144
        dwMinBitRate                  6082560
        dwMaxBitRate                 12165120
        dwMaxVideoFrameBufferSize       50688
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         5
        bmCapabilities                   0x01
          Still image supported
        wWidth                            160
        wHeight                           120
        dwMinBitRate                  4608000
        dwMaxBitRate                  9216000
        dwMaxVideoFrameBufferSize       38400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         6
        bmCapabilities                   0x01
          Still image supported
        wWidth                            544
        wHeight                           288
        dwMinBitRate                 37601280
        dwMaxBitRate                 75202560
        dwMaxVideoFrameBufferSize      313344
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         7
        bmCapabilities                   0x01
          Still image supported
        wWidth                            432
        wHeight                           240
        dwMinBitRate                 24883200
        dwMaxBitRate                 49766400
        dwMaxVideoFrameBufferSize      207360
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         8
        bmCapabilities                   0x01
          Still image supported
        wWidth                            320
        wHeight                           176
        dwMinBitRate                 13516800
        dwMaxBitRate                 27033600
        dwMaxVideoFrameBufferSize      112640
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         9
        bmCapabilities                   0x01
          Still image supported
        wWidth                            640
        wHeight                           360
        dwMinBitRate                 55296000
        dwMaxBitRate                110592000
        dwMaxVideoFrameBufferSize      460800
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                             6
        bDescriptorType                    36
        bDescriptorSubtype                 13 (COLORFORMAT)
        bColorPrimaries                     1 (BT.709,sRGB)
        bTransferCharacteristics            1 (BT.709)
        bMatrixCoefficients                 4 (SMPTE 170M (BT.601))
      VideoStreaming Interface Descriptor:
        bLength                            11
        bDescriptorType                    36
        bDescriptorSubtype                  6 (FORMAT_MJPEG)
        bFormatIndex                        2
        bNumFrameDescriptors               11
        bFlags                              1
          Fixed-size samples: Yes
        bDefaultFrameIndex                  1
        bAspectRatioX                       0
        bAspectRatioY                       0
        bmInterlaceFlags                 0x00
          Interlaced stream or variable: No
          Fields per frame: 1 fields
          Field 1 first: No
          Field pattern: Field 1 only
        bCopyProtect                        0
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         1
        bmCapabilities                   0x01
          Still image supported
        wWidth                            640
        wHeight                           480
        dwMinBitRate                110592000
        dwMaxBitRate                221184000
        dwMaxVideoFrameBufferSize      921600
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         2
        bmCapabilities                   0x01
          Still image supported
        wWidth                            352
        wHeight                           288
        dwMinBitRate                 36495360
        dwMaxBitRate                 72990720
        dwMaxVideoFrameBufferSize      304128
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         3
        bmCapabilities                   0x01
          Still image supported
        wWidth                            320
        wHeight                           240
        dwMinBitRate                 27648000
        dwMaxBitRate                 55296000
        dwMaxVideoFrameBufferSize      230400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         4
        bmCapabilities                   0x01
          Still image supported
        wWidth                            176
        wHeight                           144
        dwMinBitRate                  9123840
        dwMaxBitRate                 18247680
        dwMaxVideoFrameBufferSize       76032
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         5
        bmCapabilities                   0x01
          Still image supported
        wWidth                            160
        wHeight                           120
        dwMinBitRate                  6912000
        dwMaxBitRate                 13824000
        dwMaxVideoFrameBufferSize       57600
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         6
        bmCapabilities                   0x01
          Still image supported
        wWidth                            544
        wHeight                           288
        dwMinBitRate                 56401920
        dwMaxBitRate                112803840
        dwMaxVideoFrameBufferSize      470016
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         7
        bmCapabilities                   0x01
          Still image supported
        wWidth                            432
        wHeight                           240
        dwMinBitRate                 37324800
        dwMaxBitRate                 74649600
        dwMaxVideoFrameBufferSize      311040
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         8
        bmCapabilities                   0x01
          Still image supported
        wWidth                            320
        wHeight                           176
        dwMinBitRate                 20275200
        dwMaxBitRate                 40550400
        dwMaxVideoFrameBufferSize      168960
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         9
        bmCapabilities                   0x01
          Still image supported
        wWidth                            640
        wHeight                           360
        dwMinBitRate                 82944000
        dwMaxBitRate                165888000
        dwMaxVideoFrameBufferSize      691200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                        10
        bmCapabilities                   0x01
          Still image supported
        wWidth                            800
        wHeight                           480
        dwMinBitRate                138240000
        dwMaxBitRate                276480000
        dwMaxVideoFrameBufferSize     1152000
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                        11
        bmCapabilities                   0x01
          Still image supported
        wWidth                           1024
        wHeight                           768
        dwMinBitRate                283115520
        dwMaxBitRate                566231040
        dwMaxVideoFrameBufferSize     2359296
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                             6
        bDescriptorType                    36
        bDescriptorSubtype                 13 (COLORFORMAT)
        bColorPrimaries                     1 (BT.709,sRGB)
        bTransferCharacteristics            1 (BT.709)
        bMatrixCoefficients                 4 (SMPTE 170M (BT.601))
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       1
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              4 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x1400  3x 1024 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       2
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              4 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0c00  2x 1024 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       3
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              4 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0400  1x 1024 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       4
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              4 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               1
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         2
      bInterfaceCount         2
      bFunctionClass          1 Audio
      bFunctionSubClass       0 
      bFunctionProtocol       0 
      iFunction               5 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      1 Control Device
      bInterfaceProtocol      0 
      iInterface              5 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdADC               1.00
        wTotalLength       0x002b
        bInCollection           1
        baInterfaceNr(0)        3
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             1
        wTerminalType      0x0201 Microphone
        bAssocTerminal          0
        bNrChannels             1
        wChannelConfig     0x0000
        iChannelNames           0 
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                13
        bDescriptorType        36
        bDescriptorSubtype      6 (FEATURE_UNIT)
        bUnitID                 5
        bSourceID               1
        bControlSize            6
        bmaControls(0)     0x000000000003
          Mute Control
          Volume Control
        iFeature                0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             3
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bSourceID               5
        iTerminal               0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        3
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              5 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        3
      bAlternateSetting       1
      bNumEndpoints           1
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              5 
      AudioStreaming Interface Descriptor:
        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           3
        bDelay                  1 frames
        wFormatTag         0x0001 PCM
      AudioStreaming Interface Descriptor:
        bLength                32
        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bNrChannels             1
        bSubframeSize           2
        bBitResolution         16
        bSamFreqType            8 Discrete
        tSamFreq[ 0]        48000
        tSamFreq[ 1]        44100
        tSamFreq[ 2]        24000
        tSamFreq[ 3]        22050
        tSamFreq[ 4]        16000
        tSamFreq[ 5]        12000
        tSamFreq[ 6]        11025
        tSamFreq[ 7]         8000
      Endpoint Descriptor:
        bLength                 9
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes           13
          Transfer Type            Isochronous
          Synch Type               Synchronous
          Usage Type               Data
        wMaxPacketSize     0x0064  1x 100 bytes
        bInterval               4
        bRefresh                0
        bSynchAddress           0
        AudioStreaming Endpoint Descriptor:
          bLength                 7
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x01
            Sampling Frequency
          bLockDelayUnits         1 Milliseconds
          wLockDelay         0x0000
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        3
      bAlternateSetting       2
      bNumEndpoints           1
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              5 
      AudioStreaming Interface Descriptor:
        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           3
        bDelay                  1 frames
        wFormatTag         0x0001 PCM
      AudioStreaming Interface Descriptor:
        bLength                32
        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bNrChannels             1
        bSubframeSize           1
        bBitResolution          8
        bSamFreqType            8 Discrete
        tSamFreq[ 0]        48000
        tSamFreq[ 1]        44100
        tSamFreq[ 2]        24000
        tSamFreq[ 3]        22050
        tSamFreq[ 4]        16000
        tSamFreq[ 5]        12000
        tSamFreq[ 6]        11025
        tSamFreq[ 7]         8000
      Endpoint Descriptor:
        bLength                 9
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes           13
          Transfer Type            Isochronous
          Synch Type               Synchronous
          Usage Type               Data
        wMaxPacketSize     0x0032  1x 50 bytes
        bInterval               4
        bRefresh                0
        bSynchAddress           0
        AudioStreaming Endpoint Descriptor:
          bLength                 7
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x01
            Sampling Frequency
          bLockDelayUnits         1 Milliseconds
          wLockDelay         0x0000

`
2.视频传输
请参考:
image.png
注意下
A. 每次传输都需要填充头部信息
image.png
B. 虚拟设备需要驱动提供定时机制控制传输频率,不然会导致系统锁死

3.PTZ控制
参考下面的内容
image.png

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