MPEG-4

MPEG-4 Overview

Video is commonly compressed to an MPEG-4 format for playback on the mobile phone (3GP and MP4 are the most common formats).

MPEG-4 is an international standard to define, encode, and play back time-based media, like video. It is from the same committee, the Moving Pictures Expert Group (MPEG), that established MPEG-1 and MPEG-2 as standards for digital video.

The MPEG-4 file format, called MP4, is based on Apple QuickTime. When you see the extension .mp4 it is referencing the file format.

Video files with the .3gp extension (3GP) support one of the MPEG-4 standards. See the related article on the 3GP video format.

How Video Compression Works

Compressed video may be compared to frozen concentrated orange juice. By removing water from freshly squeezed orange juice at the packing house, canned frozen juice can travel great distances at the fraction of the weight and volume of the original liquid. When the consumer mixes the water back into the concentrated juice, they are returning the juice to its original weight and volume. Compression removes the bulk of data from a video file then returns that bulk to the file when it is decompressed. Of course, the decompressed video is not exactly like the original file, although good compression will minimize the apparent difference. You prefer freshly squeezed orange juice? Tough.
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