iphone - CVPixelBuffer リーク

Question

次のように CVPixelBuffer バッファを作成して使用します。

            //Create buffer
            CVPixelBufferRef conversionBuffer = nil;
            if (indx < [self.sideImageList count] - 1)
            {
                UIImageView *tempImageView = [self.sideImageList objectAtIndex:indx + 1];
                CGRect originalBackgroundFrame = [tempImageView frame];
                UIView *tempView = [tempImageView.subviews objectAtIndex:0];
                [tempView removeFromSuperview];
                tempImageView.layer.borderColor = [UIColor clearColor].CGColor;
                [tempImageView setFrame:CGRectMake(0, 0, kVideoWidth, kVideoHeight)];

                UIImage *backgroundImage = [UIImage imageFromView:tempImageView];

                [tempImageView addSubview:tempView];
                tempImageView.layer.borderColor = [UIColor yellowColor].CGColor;
                [tempImageView setFrame:originalBackgroundFrame];

                UIImage *resizedBackground = [ICVideoViewController imageWithImage:backgroundImage 
                                                                      scaledToSize:CGSizeMake(kVideoWidth, kVideoHeight)];
                UIImage *appendedImage = [ICVideoViewController appendImage:resizedBackground
                                                                         to:conversionImage 
                                                                    atPoint:CGPointMake((kVideoWidth - conversionImage.size.width)/2,
                                                                                        (kVideoHeight - conversionImage.size.height)/2)
                                                                 otherPoint:CGPointZero];

                //Fill Buffer
                conversionBuffer = [ICVideoViewController pixelBufferFromCGImage:[appendedImage CGImage] size:CGSizeMake(kVideoWidth, kVideoHeight)];
            }
            else
            {
                //Fill buffer
                conversionBuffer = [ICVideoViewController pixelBufferFromCGImage:[conversionImage CGImage] size:CGSizeMake(kVideoWidth, kVideoHeight)];
            }
            while (adaptor.assetWriterInput.readyForMoreMediaData==NO)
            {
                [NSThread sleepForTimeInterval:0.1];
            }
            if (indx == [self.sideImageList count] - 1)
            {
                break;
            }
            [adaptor appendPixelBuffer:conversionBuffer withPresentationTime:CMTimeMake((frameRate*i)+frames-1, frameRate)];

            while (adaptor.assetWriterInput.readyForMoreMediaData==NO)
            {}
            //release buffer
            CVPixelBufferRelease(conversionBuffer);

バッファを設定するために使用するメソッドは..どこかからこのメソッドを取得しましたが、何か問題があるようには見えません..

 + (CVPixelBufferRef) pixelBufferFromCGImage:(CGImageRef)image size:(CGSize)size
 {
 NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                         [NSNumber numberWithBool:YES],     kCVPixelBufferCGImageCompatibilityKey,
                         [NSNumber numberWithBool:YES],  kCVPixelBufferCGBitmapContextCompatibilityKey,
                         nil];
 CVPixelBufferRef pxbuffer = NULL;
 CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault, size.width,
                                      size.height, kCVPixelFormatType_32ARGB, (CFDictionaryRef) options, 
                                      &pxbuffer);

 NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);

CVPixelBufferLockBaseAddress(pxbuffer, 0);
void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);
NSParameterAssert(pxdata != NULL);

CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(pxdata, size.width,
                                             size.height, 8, 4*size.width, rgbColorSpace, 
                                             kCGImageAlphaNoneSkipFirst);
NSParameterAssert(context);



CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image), 
                                       CGImageGetHeight(image)), image);
CGColorSpaceRelease(rgbColorSpace);
CGContextRelease(context);

CVPixelBufferUnlockBaseAddress(pxbuffer, 0);
return pxbuffer;
 }

このメソッドでリークが発生しているようです（礼儀のリークツール）が、何が間違っているのかまだわかりません。