[LAU] FW: audio format

[Benoît Rouits]

Le 28/05/2013 06:12, Ivica Ico Bukvic a écrit :
> Got this email a couple days ago and it appears that the author wishes
> to share this with the FOSS community. Please forward comments to Pierre
> (copied here).
>
> Best wishes,
>
> Ico
>
> *From:*pierre jocelyn andre [mailto:temps.jo at gmail.com]
> *Sent:* Sunday, May 19, 2013 5:28 PM
> *To:* ico at linuxaudio.org
> *Subject:* audio format
>
> Hello,
> sorry for my poor English,
> can you look behind this link audio format.
> http://letime.net/vocale
> Regards
>
>

Hello LAU list, Hello Pierre,

I was surpised and yet seduced by the reading of the page (see above) 
relating to an audio coding format from Pierre Jocelyn.
It is written in french. But found the idea imaginative enough to be 
worth shortly described in this list too. So, as far as i understood, 
the idea is to split the signal into a real-time (un-derminable) part 
and a predetermined part that can be extracted and shared separately to 
lossily reproduce the original audio signal.

The implementation was to encode the signal in a stream of tuples of 3 
integer values where the third one is a key of a non-resonant filter 
parameter, the second value is a step response duration, and the first 
value is the signed step amplitude.

The stream is very light then, but the dictionnary of filters can be 
heavy. What is interseting is the possibility to share families of 
dictionnaries for a certain kind of sounds (speech, music, ...) appart 
from the stream, so that hardware could have presets dicts and only the 
stream of variable-length steps is transmitted.

I find that fun, but i wonder if GSM phones does already use that kind 
of principles with their adaptative sound repdroduction algorithms.
Correct me if i'm wrong...
Cheers, Benoît.