[Mp4-tech] MP4 CELP

[Ramzi Elkhater]

Hello All,
    I havent seen much discussion regarding the MP4 CELP , however I'm 
hoping that someone will be able to help me.
    I have a question regarding the windowing for LPC analysis. 
According to the informative Annex 3.B (pp.94)in the CELP documentation 
(subpart 3 of the ISO) it says that LPC analysis is performed multiple 
times per frame each time with a different window and offset, yielding 
multiple sets of LPC coefficients per frame.
   The question is which one of these coefficients are transmitted, 
since to my understanding only one set of LPC coefficients per frame are 
expected at the decoder.
note: I looked at the refrence software and it seems the coeffients from 
the last LPC analysis are used and the rest simply ignored. which does 
not make much sense.
Thank you in advance for all your help.
Ramzi Elkhater,