iOS AVCaptureSession - How to get/set the number of frames per second recorded?

Question

I\'m new to AVCaptureSession and wish to better understand how to work with it. So I managed capturing the video stream as separated CIImages and convert them to UIImages. Now I

Answer 1

To set the capture session frame rate, you have to set it on the device using device.activeVideoMinFrameDuration and device.activeVideoMaxFrameDuration (if necessary).

In Swift 4 you can do something like this:

extension AVCaptureDevice {
    func set(frameRate: Double) {
    guard let range = activeFormat.videoSupportedFrameRateRanges.first,
        range.minFrameRate...range.maxFrameRate ~= frameRate
        else {
            print("Requested FPS is not supported by the device's activeFormat !")
            return
    }

    do { try lockForConfiguration()
        activeVideoMinFrameDuration = CMTimeMake(value: 1, timescale: Int32(frameRate))
        activeVideoMaxFrameDuration = CMTimeMake(value: 1, timescale: Int32(frameRate))
        unlockForConfiguration()
    } catch {
        print("LockForConfiguration failed with error: \(error.localizedDescription)")
    }
  }
}

And call it

device.set(frameRate: 60)