iPhone 4 AVFoundation : Capture from front and rear cameras simultaneously

问题

I was wondering if it was possible to capture from both cameras simultaneously using AVFoundation framework. Specifically, my question is whether both front and rear AVCaptureDevices can be active at the same time or not.

Currently I know that an AVCaptureSession instance can support only one input (and output). I create two AVCaptureSessions, attach front camera device to one and rear to other, I then point the outputs of the sessions to different SampleBufferDelegate functions. What I see is that one delegate function is active for a few frames, then the other takes over. It seems as if AVFoundation somehow turns off a camera device if another one is being used. Can anyone confirm this or share their experiences regarding this subject?

Thanks in advance

回答1:

Answering my own question:

1. This is not possible.
2. Switching between front and rear camera to emulate similar behavior is too slow (Takes about 500ms per switch according to my tests)

Source: https://devforums.apple.com/message/369748#369748

来源：https://stackoverflow.com/questions/4807619/iphone-4-avfoundation-capture-from-front-and-rear-cameras-simultaneously