MP2 (MPEG Audio Layer 2) is a Moving Picture Experts Group audio format that comes with a .mp2 filename extension. Like MP3, MP2 is a lossy format and is mostly used for sound broadcasting. Because a limited number of audio players support MP2, it’s best to convert it to MP3, which is a universal format.
AC3 is an audio format designed by Dolby Digital to offer surround sound listening. This format is available on most Blu-ray and DVD media files and is played using a Dolby Digital DVD Player. Interestingly, AC3 can be output in up to six speakers of a home stereo system. On a computer, AC3 can be opened on VLC Media Player, Apple QuickTime Player, and Windows Media Player.
VLC Media Player Apple QuickTime Player Windows Media Player