GSM library - gsm_explode

[rg]

Archived from groups: comp.compression,comp.speech.research,rec.audio.tech (More info?)

Dear all,

I have to do some GSM codec related analysis of audio and I've been using
the GSM library available from http/kbs.cs.tu-berlin.de/~jutta/toast.html.
I have managed to compile the basic core API (without the toast client) in
WindowsXP. I am using the gsm_explode function to extract the information
for each frame as I process the audio. By reading through the source code
for the gsm_explode function, I have gotten some idea of what each of the 76
members of the info array mean but I would appreciate if someone could
provide some detail from the perspective of the GSM standard.

LARc 0-7 (8), which I guess represents the long-term predictor
coefficients.
Nc (1), bc(1), Mc(1), xmaxc(1) and xmc (13) (17 in total) are repeated for 4
times and (I guess) represent the short-term predictor coefficient.

I would especially appreciate it if someone could tell me what Nc, bc, Mc
and xmaxc represent.

Any help would be greatly appreciated,

Many Thanks,

RG

 

[Guest]

Archived from groups: comp.compression,comp.speech.research,rec.audio.tech (More info?)

rg wrote:

> Dear all,
>
> I have to do some GSM codec related analysis of audio and I've been using
> the GSM library available from http/kbs.cs.tu-berlin.de/~jutta/toast.html.
> I have managed to compile the basic core API (without the toast client) in
> WindowsXP. I am using the gsm_explode function to extract the information
> for each frame as I process the audio. By reading through the source code
> for the gsm_explode function, I have gotten some idea of what each of the 76
> members of the info array mean but I would appreciate if someone could
> provide some detail from the perspective of the GSM standard.
>
> LARc 0-7 (8), which I guess represents the long-term predictor
> coefficients.
> Nc (1), bc(1), Mc(1), xmaxc(1) and xmc (13) (17 in total) are repeated for 4
> times and (I guess) represent the short-term predictor coefficient.
>
> I would especially appreciate it if someone could tell me what Nc, bc, Mc
> and xmaxc represent.

Look in the file "private.h" to find these answers.

> Any help would be greatly appreciated,
>
> Many Thanks,
>
> RG

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Hawk Software
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