Method to find device's camera resolution iOS

Question

Whats the best method to find the image resolution going to be captured using setting AVCaptureSessionPresetPhoto.
I am trying to find the resolution before

Answer 1

With the function below, you can programmatically get the resolution from activeFormat before capture begins, though not before adding inputs and outputs: https://developer.apple.com/library/ios/documentation/AVFoundation/Reference/AVCaptureDevice_Class/index.html#//apple_ref/occ/instp/AVCaptureDevice/activeFormat

private func getCaptureResolution() -> CGSize {
    // Define default resolution
    var resolution = CGSize(width: 0, height: 0)

    // Get cur video device
    let curVideoDevice = useBackCamera ? backCameraDevice : frontCameraDevice

    // Set if video portrait orientation
    let portraitOrientation = orientation == .Portrait || orientation == .PortraitUpsideDown

    // Get video dimensions
    if let formatDescription = curVideoDevice?.activeFormat.formatDescription {
        let dimensions = CMVideoFormatDescriptionGetDimensions(formatDescription)
        resolution = CGSize(width: CGFloat(dimensions.width), height: CGFloat(dimensions.height))
        if portraitOrientation {
            resolution = CGSize(width: resolution.height, height: resolution.width)
        }
    }

    // Return resolution
    return resolution
}