http://virtualdubmod.sf.net
VirtualDubMod can convert both MPEG-1 and MPEG-2 files to the AVI container format, but the process is slow due to recompression with an AVI-compatible codec.
It has been awhile since working with video, but VirtualDubMod may also be capable of performing a direct stream copy of the MPEG data to a AVI container file. Open the MPEG file, select stream copy for both video and audio, then try saving the result to an AVI format.
Robert Richmond