MPEG-1, also known with the file extension of .mpg, is a compressive standard for video and audio format. It was used specially in CD disc. It was become as an international standard officially by the end of 1992. Its output quality is nearly the same as a traditional VCR, i.e. with the resolution of 352x240 and certain bitrates of 1.15Mbps. It's just too low in quality and because of that, the Video CD, which uses MPEG-1 as its core tech, couldn't make a hit in developed countries.
Generally speaking, there are 3 generations of MPEG-1, and simply known as MP1, MP2, MP3.
MPEG-1 Layer1, or MP1, is mainly used in Digital Compact Cassette (DCC).
MPEG-1 Layer2, or MP2, is now widely used in Digital Television, CD-ROM, CD-I, and VCD.
MPEG-1 Layer3, or MP3, the best known layer for us, is now used in audio encoding.
These three generations of MPEG-1 output the same quality with different compressive rate. And the compressive rate of the later generation would be faster than its predecessor.
You may be confused about how to play your CD files on your handsets or MP3 player. Then what can you do? That's simply a piece of cake. Try to use iOrgSoft Video Converter to convert .mpg to .mp3. The process would really short and you can fast convert MPEG-1 to the supportable formats for your devices.
iOrgsoft MPG Converter for Mac can nicely handle all digital video formats among muxed or demuxed MPG/MPEG, MPEG-2, MPEG-4 video and audio file standardized by the Moving Picture Experts Group (MPEG) on Mac OSX.