#import <avfoundation avfoundation.h="">

// Switching between front and back cameras

- (AVCaptureDevice *)cameraWithPosition:(AVCaptureDevicePosition)position

{

    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];

    for ( AVCaptureDevice *device in devices )

        if ( device.position == position )

            return device;

    return nil;

}

- (void)swapFrontAndBackCameras {

    // Assume the session is already running

    NSArray *inputs = self.session.inputs;

    for ( AVCaptureDeviceInput *input in inputs ) {

        AVCaptureDevice *device = input.device;

        if ( [device hasMediaType:AVMediaTypeVideo] ) {

            AVCaptureDevicePosition position = device.position;

            AVCaptureDevice *newCamera = nil;

            AVCaptureDeviceInput *newInput = nil;

            if (position == AVCaptureDevicePositionFront)

                newCamera = [self cameraWithPosition:AVCaptureDevicePositionBack];

                else

                    newCamera = [self cameraWithPosition:AVCaptureDevicePositionFront];

                    newInput = [AVCaptureDeviceInput deviceInputWithDevice:newCamera error:nil];

                    // beginConfiguration ensures that pending changes are not applied immediately

                    [self.session beginConfiguration];

            [self.session removeInput:input];

            [self.session addInput:newInput];

            // Changes take effect once the outermost commitConfiguration is invoked.

            [self.session commitConfiguration];

            break;

        }

    } 

}