[FFmpeg-soc] [soc] G.723.1 Encoder: Compute LPC coefficients

[Mohamed Naufal]

On 12 August 2010 03:36, Justin Ruggles <justin.ruggles at gmail.com> wrote:
> Mohamed Naufal wrote:
>
>> +/**
>> + * Estimate autocorrelation of the input vector.
>> [...]
>> + * Use Levinson-Durbin recursion to compute LPC coefficients from
>> + * autocorrelation values.
>> [...]
>> + * Hamming window coefficients scaled by 2^15
>
> Are these functions required to be bit-exact as defined by the
> specification or are they implementation-dependent?  I ask because they


The spec requires them to be bit-exact to the reference.

> are quite similar to our existing autocorrelation and levinson-durbin
> functions (though obviously 16-bit fixed-point rather than
> floating-point).  Also, is a Hamming window required or can some other
> window function be used?
>


A Hamming window is to be applied according to the spec.

Thanks
Naufal