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Re: Audio data format and file type - how to match?
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Re: Audio data format and file type - how to match?


  • Subject: Re: Audio data format and file type - how to match?
  • From: "tahome izwah" <email@hidden>
  • Date: Sat, 22 Jul 2006 23:39:21 +0200

Thanks... but... isn't there a simpler way to determine a compatibility matrix?

Something like...

CAGetCompatibleFileTypesFromStreamType(char *fileType, AudioFileTypeID
*type, long *numTypes);

...or CAGetCompatibleStreamTypesFromFileType() for doing the reverse?
In my humble opinion, this whole CoreAudio business seems overly
complicated and has a pretty steep learning curve. ExtAudioFile is a
step in the right direction, but some things (like matching file type
and stream format) are still very inconvenient and require a lot of
coding...

Thanks for listening,
--th


2006/7/21, Doug Wyatt <email@hidden>:

On Jul 20, 2006, at 23:13 , tahome izwah wrote:

> Hi all,
>
> I have a question about the four char codes describing the audio data
> format and the actual file types of the files that can hold such
> data... is there any call that tells me from such a four char code
> what the right file type(s) should/can be?
>
> For instance, if I let the user select from a list of encoding options
> in a save-as dialog box and he selects "MPEG-4 AAC" (corresponding to
> the four char code kAudioFormatMPEG4AAC in an
> AudioStreamBasicDescription that I set up), how do I know what file
> type I have to pass to ExtAudioFileCreateNew() to create the correct
> audio file (in this case kAudioFileM4AType)?
>
> To be future-proof, I'd not like to go through all the available file
> types manually so I guess there must be an option/call that I can
> use...?

Have a look at /Developer/Examples/CoreAudio/PublicUtility/
CAAudioFileFormats.cpp

Also in /Developer/Examples/CoreAudio/PublicUtility/Services/
AudioFileTools, try the "audioformats" tool.

Doug

--
Doug Wyatt
Core Audio, Apple


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  • Follow-Ups:
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References: 
 >Audio data format and file type - how to match? (From: "tahome izwah" <email@hidden>)
 >Re: Audio data format and file type - how to match? (From: Doug Wyatt <email@hidden>)

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