How to convert .mp4 videos .vlc format.
Converting MPEG-4 Videos directly to a VLC Playlist (.mp4 to .vlc conversion) is, per se, not possible. But you can certainly add a MP4 video to a VLC playlist, thus generating a .vlc file.
There is really no need for a conversion, since the VLC Media Player supports a large amount of media formats, including .mp4 files, and also comes with its own conversion utility accessible through the 'Media -> Convert/Save as' function.