livetrax/libs/appleutility/CoreAudio/PublicUtility/CAAudioUnitOutputCapturer.h

/*
     File: CAAudioUnitOutputCapturer.h
 Abstract: Part of CoreAudio Utility Classes
  Version: 1.1
 
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*/
#ifndef __CAAudioUnitOutputCapturer_h__
#define __CAAudioUnitOutputCapturer_h__

#include <AudioToolbox/ExtendedAudioFile.h>

/*
	Class to capture output from an AudioUnit for analysis.

	example:

	CFURL fileurl = CFURLCreateWithFileSystemPath(NULL, CFSTR("/tmp/recording.caf"), kCFURLPOSIXPathStyle, false);

	CAAudioUnitOutputCapturer captor(someAU, fileurl, 'caff', anASBD);

	{
	captor.Start();
	...
	captor.Stop();
	} // can repeat

	captor.Close(); // can be omitted; happens automatically from destructor
*/

class CAAudioUnitOutputCapturer {
public:
	enum { noErr = 0 };

	CAAudioUnitOutputCapturer(AudioUnit au, CFURLRef outputFileURL, AudioFileTypeID fileType, const AudioStreamBasicDescription &format, UInt32 busNumber = 0) :
		mFileOpen(false),
		mClientFormatSet(false),
		mAudioUnit(au),
		mExtAudioFile(NULL),
		mBusNumber (busNumber)
	{	
		CFShow(outputFileURL);
		OSStatus err = ExtAudioFileCreateWithURL(outputFileURL, fileType, &format, NULL, kAudioFileFlags_EraseFile, &mExtAudioFile);
		if (!err)
			mFileOpen = true;
	}
	
	void	Start() {
		if (mFileOpen) {
			if (!mClientFormatSet) {
				AudioStreamBasicDescription clientFormat;
				UInt32 size = sizeof(clientFormat);
				AudioUnitGetProperty(mAudioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, mBusNumber, &clientFormat, &size);
				ExtAudioFileSetProperty(mExtAudioFile, kExtAudioFileProperty_ClientDataFormat, size, &clientFormat);
				mClientFormatSet = true;
			}
			ExtAudioFileWriteAsync(mExtAudioFile, 0, NULL);	// initialize async writes
			AudioUnitAddRenderNotify(mAudioUnit, RenderCallback, this);
		}
	}
	
	void	Stop() {
		if (mFileOpen)
			AudioUnitRemoveRenderNotify(mAudioUnit, RenderCallback, this);
	}
	
	void	Close() {
		if (mExtAudioFile) {
			ExtAudioFileDispose(mExtAudioFile);
			mExtAudioFile = NULL;
		}
	}
	
	~CAAudioUnitOutputCapturer() {
		Close();
	}

private:
	static OSStatus RenderCallback(	void *							inRefCon,
									AudioUnitRenderActionFlags *	ioActionFlags,
									const AudioTimeStamp *			inTimeStamp,
									UInt32							inBusNumber,
									UInt32							inNumberFrames,
									AudioBufferList *				ioData)
	{
		if (*ioActionFlags & kAudioUnitRenderAction_PostRender) {
			CAAudioUnitOutputCapturer *This = (CAAudioUnitOutputCapturer *)inRefCon;
			static int TEMP_kAudioUnitRenderAction_PostRenderError	= (1 << 8);
			if (This->mBusNumber == inBusNumber && !(*ioActionFlags & TEMP_kAudioUnitRenderAction_PostRenderError)) {
				OSStatus result = ExtAudioFileWriteAsync(This->mExtAudioFile, inNumberFrames, ioData);
				if (result) DebugMessageN1("ERROR WRITING FRAMES: %d\n", (int)result);
			}
		}
		return noErr;
	}
	
	bool				mFileOpen;
	bool				mClientFormatSet;
	AudioUnit			mAudioUnit;
	ExtAudioFileRef		mExtAudioFile;
	UInt32				mBusNumber;
};

#endif // __CAAudioUnitOutputCapturer_h__