kExtAudioFileProperty_CodecManufacturer and client formats
kExtAudioFileProperty_CodecManufacturer and client formats
- Subject: kExtAudioFileProperty_CodecManufacturer and client formats
- From: Christopher Liscio <email@hidden>
- Date: Tue, 24 Aug 2010 10:39:41 -0400
Hey folks,
I've been noodling around and looking for ways to make my ExtAudioFile reading go a bit faster on devices w/ the hardware AAC codec.
I had a hunch that ExtAudioFile wasn't using the hardware AAC decoder by default, and noticed that iOS 4 added a nifty new property for me to assert this fact: kExtAudioFileProperty_CodecManufacturer
The header seems to indicate it was provided for _encoding_ using hardware, but I'm interested in _decoding_ using the hardware.
So, I tried it, and it didn't work. :)
However, it's not the request of the hardware decoder that fails---it's the setting of kExtAudioFileProperty_ClientDataFormat that fails.
I'm setting a deinterleaved floating-point format for reading, and ExtAudioFileSetProperty(ClientDataFormat) is returning 'perm'.
I suspect that since, according to the header, setting the ClientDataFormat "triggers the creation of the codec," this could be related to my not having access to the hardware at the time of the call.
However, an alternate explanation might be that the hardware decoder simply isn't compatible with my use of floats as the client data format?
Any insight from the CoreAudio team, or anyone else that's successfully used this, would be great!
Cheers,
Chris Liscio
http://supermegaultragroovy.com
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