Info Tech Guide

To use MPEG video files, you need a personal computer with sufficient processor speed, internal memory, and hard disk space to handle and play the typically large MPEG file (which has a file name suffix of .mpg). You also need an MPEG viewer or client software that plays MPEG files. (Note that .mp3 file suffixes indicate MP3 (MPEG-1 audio layer-3) files, not MPEG-3 standard files.) You can download shareware or commercial MPEG players from a number of sites on the Web.

The term MPEG also refers to a type of multimedia file, which is denoted by the file extension ".mpg" or ".mpeg." These files are compressed movies that can contain both audio and video. Though they are compressed, MPEG files maintain most of the original quality of the uncompressed movie. This is why many videos on the Web, such as movie trailers and music videos, are available in the MPEG format.

The MPEG compression methodology is considered asymmetric as the encoder is more complex than the decoder. The encoder needs to be algorithmic or adaptive whereas the decoder is 'dumb' and carries out fixed actions. This is considered advantageous in applications such as broadcasting where the number of expensive complex encoders is small but the number of simple inexpensive decoders is large.

The MPEG's (ISO's) approach to standardization is novel, because it is not the encoder that is standardized, but the way a decoder interprets the bitstream. A decoder that can successfully interpret the bitstream is said to be compliant. The advantage of standardizing the decoder is that over time encoding algorithms can improve, yet compliant decoders continue to function with them.

The MPEG standards give very little information regarding structure and operation of the encoder and implementers can supply encoders using proprietary algorithms. This gives scope for competition between different encoder designs, which means better designs can evolve and users have greater choice, because encoders of different levels of cost and complexity can exist, yet a compliant decoder operates with all of them.