Re: How to apply a CIFilter to a QTCaptureOutput

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

{

OSStatus err = noErr;

if (isRecording) {

long presentationTime = [sampleBuffer presentationTime].timeValue;

long duration = [sampleBuffer duration].timeValue;

CIImage *inputImage = [CIImage imageWithCVImageBuffer:videoFrame];

[effectFilter setValue:inputImage forKey:@"inputImage"];

//How do I get CIImage back into the CVImageBufferRef?

err = ICMCompressionSessionEncodeFrame( compressionSession, videoFrame, presentationTime, duration, kICMValidTime_DisplayTimeStampIsValid, NULL, NULL, NULL );

}

If you use the code in CaptureAndCompressIPBMovie you can still adapt it to using QTKit Capture for capturing the video frames themselves. Look at the documentation for QTCaptureDecompressedVideoOutput to to see how to get the raw frames acquired by a capture session.

Good luck.

David Underwood
QuickTime Engineering

On May 28, 2008, at 10:25 AM, Brad Ford wrote:

On May 28, 2008, at 3:31 AM, Hannes Osius wrote:

Hi,

I am new to developing in Mac osx application. I trying so write a small app, that records a Video from a camera via QTCaptureDevice, apply a CIFilter and write the movie to disk.

I picked the example "MyRecorder" and setup a custom CIFilter for the QTCaptureView using the Delegates "view:willDisplayImage:" so now I see a Preview with the filter applied, but how to I write this to a movie file?

There's currently no way to get the contents of your buffer to loop back into the path that would get the frames into the movie file. You're hooking into a delegate method that lets you peek at the buffer, but not alter its contents inline. If you want to add effects and write the result to a movie file, you'll need to write the file yourself. There are examples of how to do this in CaptureAndCompressIPBMovie (disregard the Sequence Grabber sourcing code).

-Brad Ford
QuickTime Engineering
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