M2TS (MPEG-2 Transport Stream) is a Blu-ray BDAV container format that uses MPEG-2 transport stream and comes with a .m2ts filename extension. It can manipulate audio, video, and other metadata such as disc menu and subtitles. At a bare minimum, any Blu-ray player should play M2TS files easily.
MPEG-1 is a compression and encoding system defined by MPEG (Moving Pictures Experts Group). It creates multiple frame sequences of I, B, and P, with the I frame containing all picture data. The B and P frames only store information about the changes on the last I frame. Typically, MPEG-1 uses 1.2 Mbps data rate, which is the speed rate of CD-ROM.