Macos OSX Mojave上的FFMpeg访问AVFoundation usb子设备摄像头

我有一个用于VR的双USB摄像头：两个摄像头，一个USB连接。在linux上，它出现在/dev/video0和/dev/video1中，我可以使用ffmpeg-I/dev/video0进行捕获

在莫哈韦，我可以在USB集线器中看到两个设备：

USB 2.0 Hub:

Product ID: 0x0101
Vendor ID:  0x1a40  (TERMINUS TECHNOLOGY INC.)
Version:    1.11
Speed:  Up to 480Mb/sec
Location ID:    0x14200000 / 8
Current Available (mA): 500
Current Required (mA):  100
Extra Operating Current (mA):   0

    Stereo Vision 2:

    Product ID: 0x9901
    Vendor ID:  0x0ac8  (Z-Star Microelectronics Corporation)
    Version:    27.02
    Serial Number:  SN0099
    Speed:  Up to 480Mb/sec
    Manufacturer:   SHENZHEN RERVISION TECHNOLOGY
    Location ID:    0x14220000 / 10
    Current Available (mA): 500
    Current Required (mA):  500
    Extra Operating Current (mA):   0

    Stereo Vision 2:

    Product ID: 0x9902
    Vendor ID:  0x0ac8  (Z-Star Microelectronics Corporation)
    Version:    27.02
    Serial Number:  SN0100
    Speed:  Up to 480Mb/sec
    Manufacturer:   SHENZHEN RERVISION TECHNOLOGY
    Location ID:    0x14210000 / 9
    Current Available (mA): 500
    Current Required (mA):  500
    Extra Operating Current (mA):   0

但当我列出设备时，只能看到一个[0]：

ffmpeg -f avfoundation -list_devices true -i ""
    [AVFoundation input device @ 0x7fae5b501a80] AVFoundation video devices:
    [AVFoundation input device @ 0x7fae5b501a80] [0] Stereo Vision 2
    [AVFoundation input device @ 0x7fae5b501a80] [1] FaceTime HD Camera
    [AVFoundation input device @ 0x7fae5b501a80] [2] Capture screen 0

从该设备捕获从其中一个摄像头捕获

---

如何让ffmpeg同时检测第二个usb设备？

一年后我又重新讨论了这个问题。ffmpeg的更新使两台设备都能正常观看

==> Upgrading 1 outdated package: 
ffmpeg 4.1.4_2 -> 4.3.1

ffmpeg -f avfoundation -list_devices true -i "" 

[AVFoundation indev @ 0x7f85b2e00380] AVFoundation video devices:
[AVFoundation indev @ 0x7f85b2e00380] [0] Stereo Vision 2 #2
[AVFoundation indev @ 0x7f85b2e00380] [1] Stereo Vision 2
[AVFoundation indev @ 0x7f85b2e00380] [2] FaceTime HD Camera
[AVFoundation indev @ 0x7f85b2e00380] [3] Capture screen 0