MPG, The file with a .mpg extension belongs to the group of file extensions for MPEG-1 or MPEG-2 audio and video compression. MPEG-1 Part 2 video is not easily available, and this extension (MPG file format) typically points to a MPEG program stream which is defined in MPEG-1 and MPEG-2, or an MPEG transport stream which is defined in MPEG-2. Other extensions such as .m2ts also exist specifying the accurate container, in this case, MPEG-2 TS, but this has little pertinence to MPEG-1 media. The .mp3 is the most common extension for files containing MP3 audio. An MP3 file is a typical stream of raw audio; the traditional way to tag MP3 files is by writing stream data to “garbage” segments of each frame, which save the media information but are discarded by the mpg file player. This is a similar technique used to tag the AAC files, but less supported nowadays.