[Vorbis-dev] Ambisonics in Ogg Vorbis

[Richard Lee]

> It's interesting that Richard Lee's document has the note:

>  IMPORTANT CORRECTION

>  The rectangular decoders in the early 5mar06 edition is (sic) wrong.
  Please destroy any copies of that document.

This referred to a slightly inaccurate version of the RECTANGULAR decoder which was superseded by Aaron's exact solution.

It has no bearing on what we are discussing on Square decoders.
__________________

> If the W channel is stored in the AMB file at a reduced level, and I'm decoding from an AMB file, do you expect me to ignore the effect of that reduced level of the W channel when decoding?

YES.  You have to assume the AMB file is correct.  W is NOT "stored in the AMB file at a reduced level".  The signal in the AMB file IS W.

The correct Rationalised Energy Square decoder is

LB = W' - 0.7X' + 0.7Y' etc	Eqn 4.2 Rationalised Square Decoder

from "SHELF FILTERS ..."   or a scaled version of this.  This gives best results if you do not use Shelf filters.

I have asked Martin Leese to correct his

http://www.ambisonia.com/Members/etienne/Members/mleese/file-format-for-b-format

page to clarify all this.



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