What does MP3 stand for? Music Player 3? Were there MP1’s and MP2’s? Will there be a MP4?
MP3 is short for MPEG Audio Layer 3. MPEG stands for Moving Picture Experts Group - a consortium that developed the MP3 standard. MPEG has developed a number of standards over the years for audio and video compression.
I know there was an MP2 standard - I used to use it. There is an MP4 standard, but it hasn’t been widely adopted yet.
To clarify and elaborate on Jeff Lichtman’s accurate post:
There is an MPEG1 Video standard. These are the traditional .mpg and .mpeg files you see floating around. There are, at this time, three MPEG1 Audio standards:
MPEG1 Layer 1, also known as MP1. This is the simplest MPEG Audio encoding, and is targeted to provide CD quality audio at about 320kbps. It’s not used anywhere.
MPEG1 Layer 2, also known as MP2. This is more complex than MP1, but much less so than MP3. It’s targeted to provide CD quality audio at about 256kbps and is used in VideoCDs, SVCDs, and in some DVDs, as well as in commercial radio.
MPEG1 Layer 3, also known as MP3. This is the most complex MPEG1 Audio encoding method and is targeted to provide CD quality audio at about 128kbps.
Note that the targeted bitrates for CD quality are actually for “near CD quality.” Basically, the point where it will sound somewhat “like” a CD, not actually as good as the CD.
The MPEG2 standard, of which MPEG2 Video is used for DVDs, also defined an audio encoding method called Advanced Audio Coding, or AAC. AAC is target to achieve near-CD quality at 96kbps. AAC isn’t used in DVDs, but is used in Apple’s Quicktime coding and in their new subscription music downloading system.
At this time, the state of the art in video encoding is the MPEG4 Video standard. These files are usually given the extension .MP4, but there is no new MPEG4 Audio standard, MPEG4 uses AAC from the MPEG2 specification. Most MPEG4 Video files use either AAC, AC3 (Dolby Digital), or MP3 for their audio tracks.