MPEG/MPG is not actually a format but short for Moving Picture Experts Group, a working group of ISO/IEC that develops video and audio encoding standards. But in most cases MPEG is taken for the name of the standard formats introduced by that group.
There are several MPEG formats, all standardized.
MPEG-1 is initial video and audio compression standard. The video quality of this standard is almost as good as a VHS tape.
MPEG-2 compared with MPEG-1, it has better quality of coding, multi-channel sound and higher image resolution. Due to all this MPEG-2 became standard in digital television and DVD industry.
MPEG Audio Layer-3 is used for audio compression and creates almost CD quality sound. Previous versions were MPEG Audio Layer 1 and 2. Today most people know this format as MP3.
MPEG-4 was created to stream DVD quality video at lower data rates and smaller file sizes. MPEG-4 supports video/audio "objects", 3D content, sprites, text and other media types. MPEG-4 has become extremely popular due to the ability to fit a two-hour movie to a CD file retaining comparatively high quality.
MPEG-7 describes multimedia content.
MPEG-21 is supposed to become a standard as a multimedia framework.
You can use mpcstar to open files with this suffix. http://www.mpcstar.com/
