Apple

My conversion routine is heavily based on the UseExtAF class in the ConvertFile example in the CoreAudio SDK, and I'm trying to convert to Apple Lossless, which I thought would work because I can use 44.1 KHz Lossless as an ASBD for recording, and it works great.

convertedStreamDesc.mSampleRate = 44100.0;

convertedStreamDesc.mFormatID = kAudioFormatAppleLossless;

convertedStreamDesc.mChannelsPerFrame = 1;

// try to fill out this asbd

UInt32 convertedStreamDescSize = sizeof (convertedStreamDesc);

conversionErr =

AudioFormatGetProperty(kAudioFormatProperty_FormatInfo, // inProperrtyId

0, // inSpecifierSize

NULL, // inSpecifier

&convertedStreamDescSize, // ioPropertyDataSize

&convertedStreamDesc); // outPropertyData

if (conversionErr != noErr) {

[self failTo: @"AudioFormatGetProperty" withOSStatus: conversionErr];

return;

}

I fail at to get the property, with kAudioDeviceUnsupportedFormatError:

Error in AudioFormatGetProperty: Error Domain=NSOSStatusErrorDomain Code=560226676 "Operation could not be completed. (OSStatus error 560226676.)"

Is there something else I need to do to set up the ASBD? When I used lossless for recording, I only set these three parameters (formatter, channels, sample rate) and it was fine. Or am I just doing it wrong?

Thanks in advance for any suggestions.

--Chris