A veg to mp4 conversion seems to be mainly related to attempts to export projects from Sonic Foundry (.veg) as MPEG-4 video files (.mp4).
You can "convert" .veg projects using the File ► Render as.. function. There are several options for saving the project, including WMV, MP4, MOV and some other multimedia formats. Just do not forget to unselect like loop region or the resulting file will be just 1 or couple second long.
Updated: October 31, 2016