An umbrella term for a variety of handheld devices that play back audio, video or both. Today, every smartphone is a portable media player; however, prior to the smartphone explosion in the 2007 ...

(1) A handheld device that plays video in the MPEG-4 movie file format. See MP4 and portable video player. (2) Any media player software or Blu-ray/DVD player that supports the MP4 movie file format.

Portable CDs were a terrible idea, but Moondrop reckons it can sell its version to audiophiles thanks to support for hi-res codecs.