MP4 Player is the best tool for Movie and music lovers nowadays,as it has caught up with the release of countless devices that can easily store up to 20,000 songs and 100 hours of video since the advent of converting normally large audio and video files into smaller file sizes without sacrificing the quality of the sound or the image. Differences between MP3 Players and MP4 Players Memory:Seemingly,the memory volume of MP4 Player is much bigger than that of MP3 Player,as each file of MP4 Player is even bigger than that of MP3 Player.You know,MP3 Player only can store MP3 format music and TXT format file,but MP4 Player not only can store those documents MP3 Player can,but also includes AVI/ASF/FLV and other video format files.