Luigi Auriemma

edit: I'm pulling the project.

Uhmm in these days I can't help you because I have other projects in mind and lately I have lost any interest for game related software.
Anyway after a very quick pass of hex editor it seemed to have some fields used also in the network protocol of Ventrilo but I bet you have already recognized them since are just the version, nickname, phonetic and so on.
If you have doubts about the format of some fields probably filemon could help you a bit since shows the various offset and amount of bytes read.

I'm reviving the project. I have figured out much of everything about this VRF container format and wrote a simple program that works for it.

All voice streams are saved unchanged and are in order by xmit event. The header is 10552 bytes fixed in length. The audio segment table is stored in memory and is appended to the file when recording is stopped (recovery is possible).

unvrf:
The structs in this source code are very similar to that in the Vent protocol.
The program supports both version 2 and 3 of Vent's VRF.

EDIT: Links are dead/outdated. Go to mangler.org for more info.