How to fix leak CVPixelBuffer

问题

please tell me where is leak in this code...

//here I did video with images from Document Directory

- (void) testCompressionSession:(NSString *)path
{
if ([[NSFileManager defaultManager] fileExistsAtPath:path]) {
    [[NSFileManager defaultManager] removeItemAtPath:path error:nil];
}
NSArray *array = [dictInfo objectForKey:@"sortedKeys"];

NSString *betaCompressionDirectory = path;
NSError *error = nil;

unlink([betaCompressionDirectory UTF8String]);

NSLog(@"array = %@",array);
NSData *imgDataTmp = [NSData dataWithContentsOfFile:[projectPath stringByAppendingPathComponent:[array objectAtIndex:0]]];
NSLog(@"link : %@",[projectPath stringByAppendingPathComponent:[array objectAtIndex:0]]);
CGSize size = CGSizeMake([UIImage imageWithData:imgDataTmp].size.width, [UIImage imageWithData:imgDataTmp].size.height);
//----initialize compression engine
NSLog(@"size : w : %f, h : %f",size.width,size.height);
AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:[NSURL fileURLWithPath:betaCompressionDirectory]
                                                       fileType:AVFileTypeQuickTimeMovie
                                                          error:&error];
NSParameterAssert(videoWriter);
if(error)
    NSLog(@"error = %@", [error localizedDescription]);

NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:AVVideoCodecH264, AVVideoCodecKey,
                               [NSNumber numberWithInt:size.width], AVVideoWidthKey,
                               [NSNumber numberWithInt:size.height], AVVideoHeightKey, nil];
AVAssetWriterInput *writerInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSettings];

NSDictionary *sourcePixelBufferAttributesDictionary = [NSDictionary dictionaryWithObjectsAndKeys:
                                                       [NSNumber numberWithInt:kCVPixelFormatType_32ARGB], kCVPixelBufferPixelFormatTypeKey, nil];

AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerInput
                                                                                                                 sourcePixelBufferAttributes:sourcePixelBufferAttributesDictionary];
NSParameterAssert(writerInput);
NSParameterAssert([videoWriter canAddInput:writerInput]);

if ([videoWriter canAddInput:writerInput])
    NSLog(@"I can add this input");
else
    NSLog(@"i can't add this input");

[videoWriter addInput:writerInput];

[videoWriter startWriting];
[videoWriter startSessionAtSourceTime:kCMTimeZero];

dispatch_queue_t    dispatchQueue = dispatch_queue_create("mediaInputQueue", NULL);

[writerInput requestMediaDataWhenReadyOnQueue:dispatchQueue usingBlock:^{
    //BOOL isEffect = NO;
    int i = 0;
    float totalTime = 0.0f;
    float nextTime = 0;
    if ([writerInput isReadyForMoreMediaData]) {
        while (1)
        {   
            if (i <= [array count] && i > 0) {
                nextTime = [[dictInfo objectForKey:[array objectAtIndex:i-1]] floatValue];
            }
            totalTime += i == 0 ? 0 : nextTime;
            CMTime presentTime=CMTimeMake(totalTime, 1);
            printf("presentTime : %f  ",CMTimeGetSeconds(presentTime));
            if (i >= [array count]) 
            {
                NSData *imgData = [NSData dataWithContentsOfFile:[projectPath stringByAppendingPathComponent:[array objectAtIndex:i-1]]];
                UIImage* tmpImg = [UIImage imageWithData:imgData];
                tmpImg = [self imageWithImage:tmpImg scaledToSize:size];
                while ( !writerInput.readyForMoreMediaData)
                {
                    sleep(0.01);
                }
                CVPixelBufferRef buffer = NULL;
                buffer = (CVPixelBufferRef)[self pixelBufferFromCGImage:[tmpImg CGImage] size:size];
                [adaptor appendPixelBuffer:buffer withPresentationTime:CMTimeMake(totalTime-nextTime+(nextTime/2.0), 1)];
                NSLog(@"%f",totalTime-nextTime+(nextTime/2.0));
                [writerInput markAsFinished];
                [videoWriter finishWriting];
                //CVPixelBufferPoolRelease(adaptor.pixelBufferPool);
                [videoWriter release];
                break;
            } else {
                NSData *imgData = [NSData dataWithContentsOfFile:[projectPath stringByAppendingPathComponent:[array objectAtIndex:i]]];
                UIImage* tmpImg = [UIImage imageWithData:imgData];
                //tmpImg = [self imageWithImage:tmpImg scaledToSize:size];
                //UIImageWriteToSavedPhotosAlbum(tmpImg, nil, nil, nil);
                while (!adaptor.assetWriterInput.readyForMoreMediaData && !writerInput.readyForMoreMediaData)
                {
                    sleep(0.01);
                }
                CVPixelBufferRef buffer = NULL;
                buffer = (CVPixelBufferRef)[self pixelBufferFromCGImage:[tmpImg CGImage] size:size];
                if (buffer)
                {
                    if(![adaptor appendPixelBuffer:buffer withPresentationTime:presentTime])
                        NSLog(@"FAIL");
                    else
                        NSLog(@"Success:%d",i);
                    CVPixelBufferRelease(buffer);
                }
            }
    i++;
        }
    }
}];

//and here I did CVPixelBufferRef from CGImageRef

- (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, kCGImageAlphaPremultipliedFirst);
NSParameterAssert(context);

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

CVPixelBufferUnlockBaseAddress(pxbuffer, 0);
return pxbuffer;

leak log is :

CVObject CFRetain 00:37.957.985 2 0x1ecae0 0 CoreVideo CVPixelBufferPool::createPixelBuffer(__CFAllocator const*, __CFDictionary const*, int*) Malloc 96 Bytes Malloc 00:40.015.872 1 0x1f0750 96 CoreVideo CVBuffer::init() CVPixelBuffer Malloc 00:40.969.716 1 0x1f2570 96 CoreVideo CVObject::alloc(unsigned long, __CFAllocator const*, unsigned long, unsigned long)

回答1:

Look here:

CVPixelBufferRef buffer = NULL;
CVPixelBufferPoolCreatePixelBuffer(NULL, adaptor.pixelBufferPool, &buffer);
CVPixelBufferLockBaseAddress(buffer, 0);
buffer = (CVPixelBufferRef)[self pixelBufferFromCGImage:[tmpImg CGImage] size:size];

first a pixel buffer gets created and its address put info buffer variable, then the same variable gets overwritten by pixelBufferFromCGImage, so its previous content cannot be released any more.

EDIT

you've just removed the code I used, so my answer is now no more applicable.

Now this part:

CVPixelBufferRef buffer = NULL;
buffer = (CVPixelBufferRef)[self pixelBufferFromCGImage:[tmpImg CGImage] size:size];
[adaptor appendPixelBuffer:buffer withPresentationTime:CMTimeMake(totalTime-nextTime+(nextTime/2.0), 1)];
NSLog(@"%f",totalTime-nextTime+(nextTime/2.0));
...

You have a commented out CVPixelBufferPoolRelease(adaptor.pixelBufferPool), which is okay, since in this version you have not pixel buffer pool, but I miss here a call to CVPixelBufferRelease(buffer).

来源：https://stackoverflow.com/questions/8645452/how-to-fix-leak-cvpixelbuffer