Hi all,

I'm suffering from poor sound quality on my setup, using GSM on the a-leg and PCMU on the b-leg. I'm thinking it's mostly bandwidth/network related, so I'm considering switching to G729 on both legs, as that is the only compressed codec that the b-leg supports (it's a sip gateway).

But a complicating factor is that the calls need to be recorded in mp3.

So I have some questions that I hope someone here can answer:

Does transcoding (for example GSM<>PCMU) negatively affect the sound quality, even when the CPU seems to be ok with it?
If yes, does recording 2 legs using the same codec (say G729) to a different sound format (say mp3) have the same (negative) effect?
When you use G729 on both legs (using mod_com_g729), it is even possible to record to mp3?

Thank you,

Kees