I am wondering if Sorenson Squeeze 4.5 MP4 option is the same file as produced for DivX? And what is AVIX then?

Namely, if I want to produce a AVIX (or DIVX) playable file, must I get the DIVX encoder then? Any other software available to do that?

My source will be 720p HD coming from Panasonic HVX202 (DVCPRO HD) -> Canopus EDIUS -> Canopus HQ codec.

Not sure what AVIX is, but I can tell you about DIVX. You either need the DIVX encoder (I think they call it Doctor DIVX), or the codec at the minimum. Some compression software will do the actual compression as long as the codec is installed. No other software will do it unless specifically designed to do that or having the codec installed. In other words, no codec = no encoding.

Okay - thanks. Will get Doctor DIVX then. It is cheap software anyway.