ICMCompressionSessionEncodeFrame and Memory Problems

Subject: ICMCompressionSessionEncodeFrame and Memory Problems

From: Hannes Osius <email@hidden>

Date: Tue, 24 Jun 2008 14:09:47 +0200

Delivered-to: email@hidden

Hi,

I'm trying to create a Movie via ICMCompressionSession. The input comes from an QTCaptureSession via the QTCaptureDecompressedVideoOutput. I started to feed the frame over the didOutputVideiFrame is works fine:

- (void)captureOutput:(QTCaptureOutput *)captureOutput didOutputVideoFrame:(CVImageBufferRef)videoFrame withSampleBuffer: (QTSampleBuffer *)sampleBuffer fromConnection:(QTCaptureConnection *)connection

{

err = ICMCompressionSessionEncodeFrame( mCompressionSession, videoFrame , timeStamp, [sampleBuffer duration].timeValue, kICMValidTime_DisplayTimeStampIsValid, NULL, NULL, NULL );

timeStamp = timeStamp + timescale;

}

so now I tried to modify the a CIImage that i get from videoFrame and write it into the ICMCompressionSession using an CVPixelBuffer. The pixelBuffer came from a ICMCompression-Pixelbufferpool. Now I have memory problems the app does alloc more and more memory, even if only pass an PixelBuffer directly from the pool like this:

CVImageBufferRef buffer;

theError = CVPixelBufferPoolCreatePixelBuffer(NULL, mBufferPool, &buffer);

if(theError)....

else{

CVPixelBufferRetain(buffer);

err = ICMCompressionSessionEncodeFrame( mCompressionSession, buffer , timeStamp, [sampleBuffer duration].timeValue, kICMValidTime_DisplayTimeStampIsValid, NULL, NULL, NULL );

timeStamp = timeStamp + timescale;

CVPixelBufferRelease(buffer);

}

Someday it should look like this:

CVImageBufferRef buffer;

theError = CVPixelBufferPoolCreatePixelBuffer(NULL, mBufferPool, &buffer);

if(theError)...

CVPixelBufferRetain(buffer);

theError = CVPixelBufferLockBaseAddress(buffer, 0);

if(theError)....

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

void * rasterData = CVPixelBufferGetBaseAddress(buffer);

CGContextRef cgContextRef = CGBitmapContextCreate( rasterData, CVPixelBufferGetWidth(buffer), CVPixelBufferGetHeight(buffer), 8, CVPixelBufferGetBytesPerRow(buffer), colorSpace, kCGImageAlphaPremultipliedLast);

if(cgContextRef == nil)...

CIContext * cicontext = [CIContext contextWithCGContext:cgContextRef options:nil];

CIImage* inputImage1 = [CIImage imageWithCVImageBuffer:videoFrame];

//do CIFilter stuff .....

CGImageRef cgImage = [cicontext createCGImage:inputImage1 fromRect:[inputImage1 extent]];

CGContextDrawImage(cgContextRef, [inputImage1 extent], cgImage);

err = ICMCompressionSessionEncodeFrame( mCompressionSession, buffer , timeStamp, [sampleBuffer duration].timeValue, kICMValidTime_DisplayTimeStampIsValid, NULL, NULL, NULL );

timeStamp = timeStamp +timescale;

if(err)...

CGColorSpaceRelease(colorSpace);

CGImageRelease(cgImage);

[cicontext release];

CGContextRelease(cgContextRef);

CVPixelBufferRelease(buffer);

So i must do something wrong:

- did I forget to register a Callback for clean up the buffer?

- do I have to copy the CVBufferAttachments from the videoframe to the buffer?

- do I have to call something for clean up?

- Not enough Performance? Is does no look like. i am working on an 8-Core MacPro and all CPU's are working between 50-60%.

Datails about the ICMCompressionSession:

- Codec: Appel Prores 422 HQ

- Format is Full HD 1920x1080

- Input via AJA Card

Thanks for help

Hannes Osius

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