MP2

In audio context, MP2 stands for MPEG-1/2 Layer II (see also the MPEG-2 FAQ of the MPEG Audio Subgroup), but this abbreviation is also used for MPEG-2 video files.

The tooLAME implementation of this standard still gets developed nowadays and is regarded as having a better sound quality than the original reference software:

http://mikecheng.d2.net.au/#tooLAME

Musepack can be considered as a derivative from this standard, as it is based on the same principles, but developed into a subband codec of its own with superior audio quality.

This format is currently used in broadcast like satellite, DVB and DAB.