Re: Audio Converter and Endians problem
Re: Audio Converter and Endians problem
- Subject: Re: Audio Converter and Endians problem
- From: Mark Cookson <email@hidden>
- Date: Tue, 28 Jan 2003 09:38:59 -0800
It used to be that you could download all of the headers from the Apple
Developer Support web site, though they're going to be in StuffIt file
or .smi disk image, so if you can't expand that, then it's not going to
do you any good. Search around on the Apple Developer web site, the
headers might still be there. They used to be in the MPW SDK, though I
believe that MPW has given way to Project Builder, so you might just
have to download that and see if you can expand it to get to the
headers.
You can read an AIFF or AIFC file on a PC just as easily as a Mac can
read a WAVE file (in fact, a WAVE file and an AIFF file look very
similar).
An AIFF and AIFC file have all of its fields described with big endian
values, but an AIFC file also describes a compressed data section.
Once you get to the DATA section, you have to interpret it with the
knowledge gained from parsing the format section of the AIFC. For
purposes of making things simple, endian conversion is considered to be
a compression, which is why it requires an AIFC file to contain it. In
this case that means you parse the format to know that the data is
little endian format, and then reading it as little endian data.
--
Mark Cookson
Engineering Droid
Apple Computer, Inc.
Core Audio CPU Software
5 Infinite Loop MS 305-3SQ
Cupertino, CA 95014
On Tuesday, January 28, 2003, at 03:07 AM, Richard Dobson wrote:
My problem is that I currently don't have access to a Mac system. I am
mostly lurking on this list until that situation changes, as I am
determined it will soon. But it means I don't have the development
system either, so can't read header files to find out stuff.
If this is truly an aspect of generic AIFF-C (i.e could conceviably
crop up on a file being read on an Intel platform,) it needs to be
formally documented in an external specification document, not just in
Mac developer header files. Otherwise, I have to regard it as
"undocumented". Just how public/portable is all that stuff? It is only
used for reading CDs in Macs?
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