Cannot get QCAR::Image of format RGBA8888

I am using : iPod Touch 4. iOS 5.1.1. QCAR 2.0 Here is a snapshot of my code: - (CIImage*)toCIImage { QCAR::Frame frame = currState.getFrame(); QCAR::setFrameFormat(QCAR::RGBA8888, true); for (int i = 0; i < frame.getNumImages(); i++) { const QCAR::Image *qcarImage = frame.getImage(i); NSLog(@"%d", qcarImage->getFormat()); if (qcarImage->getFormat() == QCAR::RGBA8888) { int width = qcarImage->getWidth(); int height = qcarImage->getHeight(); int bitsPerComponent = 8; int bitsPerPixel = QCAR::getBitsPerPixel(QCAR::RGBA8888); int bytesPerRow = qcarImage->getBufferWidth() * bitsPerPixel / bitsPerComponent; int size = QCAR::getBufferSize(width, height, QCAR::RGBA8888); NSData* nsData = [NSData dataWithBytesNoCopy:(void*)qcarImage->getPixels() length:size]; CIImage* image = [CIImage imageWithBitmapData:nsData bytesPerRow:bytesPerRow size:CGSizeMake(width, height) format:kCIFormatRGBA8 colorSpace:CGColorSpaceCreateDeviceRGB()]; return image; } } return nil; } I have NSLogged qcarImage->getFormat() but no image has a format of RGBA8888. Is there any other operations I need to do before setFrameFormat? I just follow the codes from ARCommons