You need to use virtualdub to make the file a avi, then encode the avi to mpeg2 using sw like hc enc.
virtualdub may not open the mp4 so you may need to install ffdshow and use that as the compressor codec.
In the ffdshow codecs is enable disable option, enable vc1 to wmv9 and the h.264 to enable.
In the ffdshow output make sure only yv12 is checked.
Then, when you can open your mp4 with virtualdub you can change compressed to direct stream copy so you don't lose resolution.
You may need to demux the audio and video before using the above proceedure: use tsmuxer to demux audio and video and run video through virtualdub as described above.
There is new, and then you are new.
This is a moral of the bears and their cereal.