[Speex-dev] using speex in a wireless network

Rafał Mielniczuk sadman at linuxfreak.pl
Wed Jun 3 12:50:57 PDT 2009


Hello,
        at the beginning I want to underline that I've read SpeeX 
documentation and did some tests. I know that SpeeX was designed for networks 
in which packets arrive without errors, or don't arrive at all.

SpeeX is very attractive if we consider low bit rates. I need to use SpeeX in 
very noisy environment, where speech quality doesn't matter, I'm interested 
in 2kb/s and 4kb/s using 8kHz sampling speed. Data will be transmitted 
wireless, so some packets would be damaged and BER will be greater than 0%.

My simple tests show, that by BER on level 1%, 2%, decoded SpeeX is possible 
to understand, sometimes I can hear inconvenient voice deformations. I wonder 
if somebody can advice me, which FEC coding methods is best to use and in 
which part of packet I should use it. My goal is to understand decoded SpeeX 
with largest BER and without unnecessary regrowing need of the bandwidth. 

Greetings

-- 
Pozdrawiam, Rafal Mielniczuk


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