Create UIImage from CMSampleBufferRef using video format kCVPixelFormatType_420YpCbCr8BiPlanarFullRange - iphone

Question

Im capturing from the iphone camera device using CVPixelFormatType_420YpCbCr8BiPlanarFullRange for faster processing of the grayscale plane (plane 0).
I am storing an amount of frames in memory for later video creation. Before I was creating the video in grayscale so I was storing only the plane that contains the luminiscense (plane 0).
Now I have to store both planes and also create a color video from them, for storing the frames I use something like this :
bytesInFrame = width * height * 2; //2 bytes per pixel, is that correct?
frameData = (unsigned char*) malloc(bytesInFrame * numbeOfFrames);
The function for creating the image from the grayscale buffer I was using :
- (UIImage *) convertBitmapGrayScaleToUIImage:(unsigned char *) buffer
withWidth:(int) width
withHeight:(int) height {
size_t bufferLength = width * height * 1;
CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, buffer, bufferLength, NULL);
size_t bitsPerComponent = 8;
size_t bitsPerPixel = 8;
size_t bytesPerRow = 1 * width;
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceGray();
if(colorSpaceRef == NULL) {
DLog(#"Error allocating color space");
CGDataProviderRelease(provider);
return nil;
}
CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault;
CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
CGImageRef iref = CGImageCreate(width,
height,
bitsPerComponent,
bitsPerPixel,
bytesPerRow,
colorSpaceRef,
bitmapInfo,
provider, // data provider
NULL, // decode
YES, // should interpolate
renderingIntent);
uint32_t* pixels = (uint32_t*)malloc(bufferLength);
if(pixels == NULL) {
DLog(#"Error: Memory not allocated for bitmap");
CGDataProviderRelease(provider);
CGColorSpaceRelease(colorSpaceRef);
CGImageRelease(iref);
return nil;
}
CGContextRef context = CGBitmapContextCreate(pixels,
width,
height,
bitsPerComponent,
bytesPerRow,
colorSpaceRef,
bitmapInfo);
if(context == NULL) {
DLog(#"Error context not created");
free(pixels);
}
UIImage *image = nil;
if(context) {
CGContextDrawImage(context, CGRectMake(0.0f, 0.0f, width, height), iref);
CGImageRef imageRef = CGBitmapContextCreateImage(context);
image = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
CGContextRelease(context);
}
CGColorSpaceRelease(colorSpaceRef);
CGImageRelease(iref);
CGDataProviderRelease(provider);
if(pixels) {
free(pixels);
}
return image;
}
I have seen that this question is similar to what I want to achieve :
kCVPixelFormatType_420YpCbCr8BiPlanarFullRange frame to UIImage conversion
But I think this would add an extra step to my conversion.
There is any way of creating a color UIImage form the buffer directly?
I would appreciate some indications.