[Asterisk-Users] Chan Capi Audio Quality Issue...

[Klaus-Peter Junghanns]

Am Di, 2004-06-01 um 14.42 schrieb Stefano Finetti:
> Well, i think i've solved the problem by myself :-)
> 
> I had to change a line in chan_capi_pvt.h:
> 
> /* was : 130 bytes Alaw = 16.25 ms audio not suitable for VoIP */
> /* now : 160 bytes Alaw = 20 ms audio */
> /* you can tune this to your need. higher value == more latency */
> #define AST_CAPI_MAX_B3_BLOCK_SIZE 160
> 
> Putting the AST_CAPI_MAX_B3_BLOCK_SIZE to 130 (16.25ms audio) solved the
> problem.
> 
> I forgot to mention that i'm using Snom105 phones. It seems that with GS
> BT101 with Ilbc firmware the value 160 works fine, but with snom it
> introduces an ugly distortion and choppy audio.
> 
This is really surprising. What codec are you using on the Snom?

> Recompiled using 130 as value, and the sound now is just really fine.
> 
> A little question to Kapejod if he reads this...
> 
> Is it possibile to put an even littler value here?
> I've tried to use 80 (= 10ms audio) but it makes impossible to start * cause
> it can't load chan_capi.so module.

the minimum size for a DATA_B3_BLOCK in capi 2.0 is 128 bytes. 

> 
> Regards,
-- 
best regards

Klaus
--
Klaus-Peter Junghanns

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