Re: Writing little-endian AIFF/AIFC files
Re: Writing little-endian AIFF/AIFC files
- Subject: Re: Writing little-endian AIFF/AIFC files
- From: tahome izwah <email@hidden>
- Date: Sun, 29 Mar 2009 17:44:33 +0200
AFAIK, only AIFC supports compressed sound files and little-endian
data counts as compression. AIFF does not support compression (and
therefore no little endian data). Personally I don't think there is
any reason why you would want to support little endian AIFC files
because you could as well use WAV which is little endian. I never
encountered little endian formatted AIFC files in practice so I'm not
sure who uses it and why (maybe it is faster to decode on Intel Macs
but I doubt that this makes a big difference on today's systems) .
Just my 2 cents though,
--th
2009/3/29 Adriaan van Os <email@hidden>:
> I have been trying to write little-endian AIFF/AIFC files, so far without
> success.
>
> The documentation on the subject seems to be sparse and I couldn't find any
> sample code. What I did find is:
>
> General info
> <http://en.wikipedia.org/wiki/Aiff> which mentions the 'sowt'
> semi-compressor
>
> CoreAudio
> <http://developer.apple.com/DOCUMENTATION/MusicAudio/Conceptual/CoreAudioOverview/SupportedAudioConverterFormats/SupportedAudioConverterFormats.html>
> which seems to imply that CoreAudio doesn't support little-endian AIFF/AIFC
> data nor the 'sowt' semi-compressor
>
> QuickTime
> <http://developer.apple.com/documentation/QuickTime/QTFF/QTFFChap3/qtff3.html>
> which suggests that QuickTime does
> support the 'sowt' semi-compressor
> <http://developer.apple.com/DOCUMENTATION/QuickTime/Conceptual/QT7UpdateGuide/Chapter03/03QT7_Update_Guide.html>
> which
> describes the kQTSCAudioPropertyID_ClientRestrictedPCMFlags constant.
>
> QuickTime Player
> The "Show Movie Inspector" of the QuickTime Player indicates if an AIFF/AIFC
> file (or at least its content data) is
> little-endian or big-endian. This also shows that the system software may
> choose to write little-endian rather than
> big-endian AIFF/AIFC files.
>
> First, I tried to wite little-endian AIFC/AIFF files with CoreAudio.
> Whatever I do, I get a "fmt?" error. Then, I tried
> QuickTime and had no success with either StandardCompressionSubTypeSound or
> StandardCompressionSubTypeAudio.
>
> So, my questions are:
>
> 1. Why and under which circumstances does the system software choose to
> write little-endian AIFF/AIFC files ?
> 2. How do application programmers write little-endian AIFF/AIFC files ?
> 3. Did I miss something or where is this documented ?
>
> SIncerely,
>
> Adriaan van Os
> www.microbizz.nl
>
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