What is the difference between MPEG 1,2 and 4?

Answer 1

Standardized in 1992, MPEG1 was intended for VHS-quality signal transmission primarily for the then-nascent digital video market and is still considered an efficient use of bandwidth and storage space. MPEG2 was created as the standard for digital broadcasting to provide higher levels of bandwidth transmission needed by, amongst others, direct satellite service (DSS) providers. MPEG1 has an average compression rate of about 1.5 megabits per second (Mbps); the largest possible compression rate for MPEG1 is slightly more than 5 Mbps. MPEG2 bitrates fall between about 3Mbps and about 15Mbps. Interestingly, at bitrates below 3 Mbps, MPEG1 actually performs better than MPEG2. This is because the higher level of precision built into the MPEG2 algorithm requires more processing than MPEG1. At lower bitrates, the percentage difference is great enough to cause significant digital artifacts to appear in MPEG2 encoding that do not appear in MPEG1. MPEG2 should not be used at bitrates lower than 3 Mbps.

Answer 2

MPEG is a standard that defines a group of audio and video coding and compression standards. MPEG-1 is used by VCD format (Visual CD format) and it was the first release. The other two are more complex, meaning they can achieve greater coding efficiency, improved bit rates and so on. Besides offering better performance they also require mor epowerful hardware!

Answer 3

If you are after some technical information about the different mpegs, you can go to the official mpeg site at
http://www.chiariglione.org/mpeg/

MPEG 1 is described as
"Coding of moving pictures and associated audio for digital storage media at up to about 1,5 Mbit/s"
http://www.chiariglione.org/mpeg/standards/mpeg-1/mpeg-1.htm
MPEG 2 is described as
"Generic coding of moving pictures and associated audio information"
http://www.chiariglione.org/mpeg/standards/mpeg-2/mpeg-2.htm
MPEG 4
http://www.chiariglione.org/mpeg/standards/mpeg-4/mpeg-4.htm
I could not get to the site they reference here
http://mpeg.telecomitalialab.com
Features and scope of mpg4
http://www.chiariglione.org/mpeg/standards/mpeg-4/mpeg-4.htm#1.