[Vorbis-dev] Ambisonics in Ogg Vorbis

[Richard Lee]

> > sox -V -S $1 -c 4 -3 -r 48000 $2 \ mixer \ 0.3536,0.3536,0.3536,0.3536,\
>  0.1768,0.1768,-0.1768,-0.1768,\ 0.1768,-0.1768,-0.1768,0.1768,\ 0,0,0,0 \
>  rabbit stat
> 
> > This then gives you a file with the channels in the format Left Front, Right Front, Left Rear, Right Rear.
> 
> This is a "cardioid" decode; fairly non-descript.  Used mainly for
> large area performance.  If your material is meant to be used at
> home, an "Energy" decoder is better and can be obtained by
> replacing +-0.1768 with +- 0.25 in the above script.

> Are you sure? Amb files store the W channel at 3dB down.

Please read 

"SHELF FILTERS for Ambisonic Decoders" from

www.ambisonia.net\Members\ricardo	for a "simple" explanation.

The full theoretical treatement is in "General Metatheory ... " which is referred to in the above paper.  Bear in mind that "General Metatheory... " doesn't use WXYZ in the same way as conventional Ambisonics.



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