Re: kExtAudioFileProperty_CodecManufacturer and client formats
Re: kExtAudioFileProperty_CodecManufacturer and client formats
- Subject: Re: kExtAudioFileProperty_CodecManufacturer and client formats
- From: Christopher Liscio <email@hidden>
- Date: Fri, 27 Aug 2010 12:16:50 -0400
Dumb question---
If the HW codecs can work with the AudioQueue API, could I not also get hardware decoding by using a pure AudioConverter, or is there some kind of secret sauce in the AudioQueue that isn't exposed yet?
I certainly wouldn't mind going that route, as the 'extra work' would be a bit more compatible with the code I'll have to inevitably dig into and change...
Also, digging through the archives, I noticed you said that ExtAudioFile _does_ have decoding access:
http://lists.apple.com/archives/coreaudio-api/2009/Sep/msg00206.html
Colour me confused! ;)
Thanks,
Chris Liscio
http://supermegaultragroovy.com
Learn _your_ music with Capo: http://capoapp.com
On Aug 25, 2010, at 1:36 PM, William Stewart wrote:
> I know it is more work, but if this is a critical feature for you, you can use the AudioQueue's offline render functionality. It allows you to use the hw codecs, and gives you back buffers of decoded audio you can then use as you need too. There is a tech note about this with some example code
>
> Bill
>
> On Aug 25, 2010, at 6:00 AM, Christopher Liscio wrote:
>
>>
>> On Aug 24, 2010, at 8:27 PM, Doug Wyatt wrote:
>>> The 'perm' error is indeed a result of an attempt to create the AudioConverter and failing due to lack of permission to use the hardware decoder.
>>
>> OK, that's what I feared.
>>
>>> The header is correct; kExtAudioFileProperty_CodecManufacturer only supports use of hardware encoders.
>>
>> D'oh! I filed rdar://8352659 to track this one.
>>
>> I'm not sure if the hardware supports MP3 decoding, but it'd be a huge performance win for some of the stuff I'm working on which does some offline audio analysis.
>>
>> Cheers,
>>
>> Chris Liscio
>> http://supermegaultragroovy.com
>> Learn _your_ music with Capo: http://capoapp.com _______________________________________________
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