[Vorbis-dev] Ambisonics in Ogg Vorbis

[Paul Martin]

On Sun, Apr 22, 2007 at 07:43:16PM +1000, Richard Lee wrote:
> Paul Martin wrote :
> 
> > If you haven't got a true Ambisonic setup, you can get a flavour by using the following script to convert a 4 channel .amb to a 4 channel "square" speaker arrangement. (The latest SoX has a bug in the mixer function, which stops it taking 16 numbers.)
> 
> > 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.

> "SHELF FILTERS for Ambisonic Decoders" from
> 
> www.ambisonia.net\Members\ricardo

Invalid URL. Use / slashes instead.

-- 
Paul Martin <pm at zetnet.net> (work)
  <pm at nowster.zetnet.co.uk> (home)