There are a huge number of portable media players in the market. Here, a list of the key features of MP4 players and MP3 players has been rounded up in order to help you pick up the model that is right for you. Music playback This is a core feature of a portable MP3 player. Most Portable Media Players support a diverse range of audio files, from the ubiquitous MP3 to Apple's AAC, to more niche formats such as FLAC and OGG. As long as MP3 and AAC files are supported it is fine, but if you need higher-quality music playback then choose a MP3 player with FLAC or ALAC support — these 'lossless' audio files have the highest quality possible. Photos and documents playback Though displaying photos is a relatively minor feature, it would be a useful item if you want to keep your holiday snaps for some solace on the soul-crushing bus to work or school. JPEG is supported almost mandatory but BMP and PNG can also be supported as a bonus. Other document types such as PDF are occasionally supported — at a pinch you would use a mini MP4 player to read an e-book. Video playback Video playback will be enjoyable for long train or bus commutes — catching up on downloaded TV show episodes or vodcasts is easy with a portable media player and a pair of headphones.MP4 players are such players which often support DIVX, WMV and MOV, and some MP4 players are even able to play FLV Flash videos from YouTube. Furthermore, some portable media players have integrated speakers, so you can place them on a table and listen to the music without headphones. The majority of MP3 players are bundled with a set of ear-bud headphones, but generally these are mediocre at best. And to buy MP3 players with a third-party pair of headphones can make sure you get the best sound quality.