[Flac-dev] Code for Ambisonics

[Brian Willoughby]

Martin,

I do not believe that there is any need for code specifically  
supporting Ambisonics.  FLAC supports conversion to and from other  
audio formats which hold multiple channels.  Ambisonics B-format  
involves channels WXYZ, C-format is UHJ or BHJ, G-Format can be any  
number of channels, but typically 5.1 on DVD.  You can work with  
Ambisonic recordings by either using individual mono files for each  
of the Ambisonic channels, or by using a 4-channel or 6-channel  
AIFF.  All of these files can be compressed into FLAC and expanded  
again without loss.

While FLAC does some special treatment of 2-channel files to detect  
correlation, this should not interfere with Ambisonic content.   
Ambisonics has much in common with mid-side encoding of dimensional  
recordings, and FLAC with automatically detect the most efficient  
compression based on any correlation.  For this reason, you might  
find smaller files with multiple stereo pairs (e.g. WX & YZ) instead  
of multiple mono files or a massive 4-channel file.

But to return to your question, exactly what kind of "support" are  
you looking for?
Where is your Ambisonic material coming from?
What format are the files?  By format, I am asking primarily what the  
file format is (RIFF/WAV, AIFF, other), but also which Ambisonic  
"format" among B-format, C-format, or G-format.

Brian Willoughby
Sound Consulting


On Mar 22, 2007, at 14:12, Martin Leese wrote:

Hi,

I have posted this three times to the flac-dev,
vorbis-dev, and ogg-dev mailing lists.

I wanted to see what code there was currently
to support Ambisonics.  So I downloaded the
code from the xiph download page for
libogg-1.1.3, libvorbis-1.1.2, vorbis-tools-1.1.1
and flac-1.1.4, but wasn't able to find anything.

If it exists then  I missed it, so could somebody
please point me to it.

Many thanks,
Martin
-- 
Martin J Leese
E-mail: martin.leese at stanfordalumni.org
Web: http://members.tripod.com/martin_leese/