Re: old mtcoreaudio code doesn't work now

On Dec 21, 2007, at 12:53 PM, Robert Ackerman wrote:

it complains about a bad method call which, indeed, does not now exist:

inConverter = [[MTConversionBuffer alloc]
       initWithSourceDescription:shtoomDescription
                    bufferFrames:inBufferSize
          destinationDescription:[MTConversionBuffer descriptionForDevice:outputDevice forDirection:kMTCoreAudioDevicePlaybackDirection]
                    bufferFrames:ceil ( [outputDevice deviceMaxVariableBufferSizeInFrames] * SR_ERROR_ALLOWANCE )];

there is no such initializer, now.

so, i need to figure out how to translate everything in my allocConterer method to what MYConversionBuffer now expects.

my old code used a AudioStreamBasicDescription object to pass to the conversion buffer init. i see that initWithSourceSampleRate ends up creating such an object within itself, so that is my clue.

i will try to refactor my code to just pass in the params that method asks for.

Hello,

Looking at the MTConversionBuffer class, there are three init methods...

- initWithSourceDevice:(MTCoreAudioDevice *)inputDevice destinationDevice:(MTCoreAudioDevice *)outputDevice

- initWithSourceSampleRate:(Float64)srcRate channels:(UInt32)srcChans bufferFrames:(UInt32)srcFrames destinationSampleRate:(Float64)dstRate channels:(UInt32)dstChans bufferFrames:(UInt32)dstFrames minimumBufferSeconds:(Float64)minBufferSeconds

- (Boolean) _initAudioConverterWithSourceSampleRate:(Float64)srcRate channels:(UInt32)srcChans destinationSampleRate:(Float64)dstRate channels:(UInt32)dstChans

It looks like first two are usable in your situation. The third creates the actual Converter -- which may or may not be all you need. Note that MTConversionBuffer is a wrapper for AudioConverterRef, which you would allocate with...

extern OSStatus AudioConverterNew(     

	const AudioStreamBasicDescription*inSourceFormat,     

	const AudioStreamBasicDescription*inDestinationFormat,     

	AudioConverterRef*outAudioConverter);  

What I would do is check elsewhere in the code and see if using MTConversionBuffer is necessary (does the wrapper provide an important functionality? or could you just use the AudioConverterRef and its accompanying setProperty/getProperty methods?)

does that help?

Jaime