UVC Camera ,AVFoundation can not start video stream

I develop a application with an uvc camera, this camera is a webcam, I use the AVFoundation library ,but when I run the code "[self.mCaptureSession startRunning]" ,I can not get the buffer, I already set the delegate, any answer will help.

The same to me.

UVC Camera ,AVFoundation can not start video stream
 
 
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