Vorbis dev - Mar 2010 - How are floor and residue used in OV Codec?

Hi All,

I have a doubt in Vorbis coding.
It is said, the encoder subtracts the floor from the MDCT of the data to  
get the residue. But in the decoder, the 'dot product' of of the floor
and
residue is done to get back the data. If subtraction is done at one end,  
addition should be done at the other end. What exactly is 'dot product'?
Can you name the function in the decoder code where it is done?

Thanks,
Niranjan
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
http://lists.xiph.org/pipermail/vorbis-dev/attachments/20100305/cd59b68a/attachment.htm