[asterisk-users] Use the NEW ulaw/alaw codecs (slower, but cleaner)

[Steve Murphy]

On Tue, 2008-11-11 at 15:19 -0600, Karl Fife wrote:
> In Asterisk 1.6, there is an option to use the 'new g.711
> algorithm'.  
> "Use the NEW ulaw/alaw codec's (slower, but cleaner)"
>  
> By slower does this mean more 'expensive', or does it instead mean
> that there will be more algorithmic latency?  Both?  Can anyone speak
> to the relative increases?
>  
> With regard to accuracy, can anyone speak to what kind of situation
> might demonstrate the benefit of the new algorithm?  i.e. transcoding,
> SpanDSP, Analog interfaces (DAHDI) etc.
>  
> Thanks
> Karl

Karl--

I was involved in merging those patches into Asterisk. They are slightly
slower than the original u/a-law algorithms, but not much slower. The
u/a-law code are the fastest codecs Asterisk has. As Kevin once said,
"1.4 x of 0 is still zero". The author of the fixes told me that his
fixes straighten out problems with coding vs. decoding that were in
the original code. In the original code, he said, after 4 or so hops,
fax transmissions would no longer work.

Hope this helps.

murf


-- 
Steve Murphy
Software Developer
Digium
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