From http://stackoverflow.com/questions/20267006/configure-ios-camera-parameters-to-avoid-banding-in-video-preview

11

_

a

- (BOOL) setupCaptureSessionParameters
{
    NSLog(@"--- Configure Camera options...");
    /*
     * Create capture session with optimal size to OpenCV processing
     */
    captureSession = [[AVCaptureSession alloc] init];
    captureSession.sessionPreset = AVCaptureSessionPreset640x480;

    AVCaptureDevice *cameraBack =[self videoDeviceWithPosition:AVCaptureDevicePositionBack];

    if ([cameraBack lockForConfiguration:nil])
    {
        NSLog(@"lockForConfiguration...");
        // No autofocus
        if ( [cameraBack isFocusModeSupported:AVCaptureFocusModeLocked])
        {
            cameraBack.focusMode = AVCaptureFocusModeLocked;

        }
        // Focus center image always
        if ( [cameraBack isFocusPointOfInterestSupported])
        {
            cameraBack.focusPointOfInterest = CGPointMake(0.5, 0.5);
        }
        // Autoexpose color is have a several change of lights
        if ( [cameraBack isExposurePointOfInterestSupported] )
        {
            cameraBack.exposureMode = AVCaptureExposureModeContinuousAutoExposure;
        }
        // Auto adjust white balance is user aim to a reflectant surface
        if ( [cameraBack isWhiteBalanceModeSupported:AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance])
        {
            cameraBack.whiteBalanceMode = AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance;
        }
        // Only Focus far
        if ( [cameraBack isAutoFocusRangeRestrictionSupported])
        {
            cameraBack.autoFocusRangeRestriction = AVCaptureAutoFocusRangeRestrictionFar;
        }
        // Choose best rate depending preset
        AVCaptureDeviceFormat *bestFormat = nil;
        AVFrameRateRange *bestFrameRateRange = nil;

        for ( AVCaptureDeviceFormat *format in [cameraBack formats] )
        {
            for ( AVFrameRateRange *range in format.videoSupportedFrameRateRanges )
            {
                if ( range.maxFrameRate > bestFrameRateRange.maxFrameRate )
                {
                    bestFormat = format;
                    bestFrameRateRange = range;
                }
            }
        }
        if (bestFormat)
        {
            cameraBack.activeFormat = bestFormat;
            cameraBack.activeVideoMinFrameDuration = bestFrameRateRange.minFrameDuration;
            cameraBack.activeVideoMaxFrameDuration = bestFrameRateRange.maxFrameDuration;
        }
        [cameraBack unlockForConfiguration];
         NSLog(@"unlockForConfiguration!");
    }
}