MPEG-4 is an internationally accepted media format but somehow Microsoft does not recognize it. This is why for some strange reason; Windows Media Player does not play your media files in MP4 format. You need to install DirectShow compatible MPEG-4 decoder packs if you want to play MP4filesusing Windows Media Player. Ligos LSX-MPEG Player is one such decoder pack that enables your Windows based computer to be able to play media files in MP4 format. As you find more and more video files made in MP4 format on internet, it is prudent to get Ligos LSXMPEG player for your computer.