[Gta04-owner] GTA04 voice routing now working!

Radek Polak psonek2 at seznam.cz
Fri Feb 3 15:02:06 CET 2012


Hi,
i have worked some more on the voice routing program.

First it has now git repository here[1]. You can play with it and improve it 
it. I have chosen LGPL license, but if you need something else please let me 
know.

Since last mail i have changed the sequence in loop - it first records from 
both cards and then plays on both card which is more logical.

The code now also ignores read errors in umts recording direction - this is 
normal before call is estabilished. When no such read error occurs it starts 
the routing loop and ends up on first read error which indicates that call was 
hung up.

I have also made the period buffers as small as possible. Now their size is 250 
frames which gives us at 8000Hz nice 31.25ms long latency. I made a call and 
got confirmed that everything is ok (no delay, no echo, sound quality ok) and 
the same success was in received call.

Next thing to do is to check if we still have echo - i have earpiece volume 
very low and no echo was noticed, but i think that with higher volume it will 
be there. But i have in my mind simple echo suppression algorithm...

So happy calling from your GTA04!

Radek

https://github.com/radekp/gta04-gsm-voice-routing


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