Direct VCD 2 RMVB conversion? (via Helix Producer?)

[RX78]

Recent I have great interset of converting some of my big mpeg files sitting in my HD to RMVB in order to save space..........

Here is my problem. When I asked Helix Producer to load a mpeg 1 (VCD) file, It refused. Then I looked at the log file, it said something like this:

unexpected file formart, C:\123.mpg may be a flat file.
missing RIFF header, C:\123.mpg is not a valid AVI file.
etc.

Since all the articles I can see are telling us how to convert from DivX to RMVB. Do I must convert my mpeg 1 files to DivX 1st ?

If so, what setting is best to conserve the quality when converting to DivX before converting to RMVB?

Thanks in advance.

[mgh]

Helix Producer accepts mpg files both 1(VCD) and 2 (DVD) directly.