[Asterisk-Users] G729 vs. gsm

[Andrew Kohlsmith]

On Saturday 28 May 2005 12:34, Rusty Shackleford wrote:
> > This is meaningless drivel.
>
> Hardly. Each conversion introduces the equivalent of "gen loss". Two
> such conversions are easily encountered, especially when dealing with a
> third-party network, and will produce (in MY subjective opinion)
> positively crappy sound.

Actually Steve's right on this one -- converting to or from ulaw is not 
costing you any quality.  recoding to g729 or any other compressed codec is.  
You can convert between ulaw and alaw 10000 times and it'll sound exactly the 
same as the original 8000Hz 16-bit sample because... well... it is.

> Yes, and your guidance is oh-so-meaningful.
> <roll eyes>

Prove you're right.  I'm solidly behind Steve here; sip to sip you're gonna be 
converting to slinear at both ends just to get the sound into your ears and 
from your mouth so there'll always be at least two conversions.  

gsm and g729 sound pretty damn good for their bitrates; that's why people use 
them.  But to say they sound identical to g711 is ... well, just plain wrong.  

-A.