MPEG1 cannot be decoded on an LC. Apple only supported MPEG1 playback on the 630/640 and rougly equivalent 5x0 Macs. And then you need to have the PDS MPEG decoder card and the AV-input card. All PowerPC Macs can decode MPEGs in software, of course. But 68ks cannot.
Pretty much the only choice is Cinepak video.
Peace,
Drew