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AMR-NB

Started by mani_assudani February 28, 2005


Hi friends,

I have implemented complete AMR-NB Enc-Dec on proprietary DSP chip.
As we know AMR-NB works on 8 rates from 12.2kb/s to 4.75kb/s.

One thing I'll still not clear is - Why in 12.2kb/s rate LPC analysis
is done twice as compared to other rates where LPC anaylsis is done
only once. What is the overall gain ?

Regards
Manish



hi mani,

doing the LPC over two overlapping windows permits to obtain a smooth
evolution of the LPC parameters (and therefore enhance the quality)
without using a lookahead like it is used in other codecs.
This technique has been used in the EFR-GSM

nacer --- In , "mani_assudani"
<mani_assudani@y...> wrote:
>
>
> Hi friends,
>
> I have implemented complete AMR-NB Enc-Dec on proprietary DSP chip.
> As we know AMR-NB works on 8 rates from 12.2kb/s to 4.75kb/s.
>
> One thing I'll still not clear is - Why in 12.2kb/s rate LPC
analysis
> is done twice as compared to other rates where LPC anaylsis is done
> only once. What is the overall gain ?
>
> Regards
> Manish




hai manish,
I also implemented this AMR NB codec on propreitery chip. can you tell me what is the maximum MIPS that you achieved???

regards
parthu