MPEG-2 for Future TV's, PC's, and CD-ROM's

Dimitris Anastassiou, professor of electrical engineering

Among Columbia University's leading digital technology researchers is Dimitris Anastassiou, professor of electrical engineering. Dr. Anastassiou's words tumble out in explanation of the important breakthrough for which he is responsible. His work will be used in the PC's and TV's of the future. Fortunately, his rapid-fire speech is not as compressed as the technology he invented.

His work makes Columbia the only University in a consortium that licenses this new technology, dubbed MPEG-2, that makes possible all forms of digital transmission - digital versatile discs (DVDs), direct satellite TV, high definition TV (HDTV), digital cable systems, personal computer video, and interactive media. MPEG-2 is a technique to compress a video signal (sequence of images) to send it, and decompress it to show it.

"This technology represents television signals with the digital 0's and 1's of a computer code,'' said Dr. Anastassiou. "It squeezes down the number of 0's and 1's to a manageable number that can satisfy the requirements of limited-capacity digital transmission channels.''

The technology furnishes sophisticated signal processing techniques that eliminate redundancy. For example, in a televised picture of a TV anchor person, the background remains the same. MPEG-2 compression tells the decoder to continue to replicate that background without constant transmission of the image. The variable images thus become the only ones that need to be transmitted and decoded.

Dr. Anastassiou's developments are complex and can be used only in conjunction with patents held by eight companies that form a portfolio of 33 patents. Together they form MPEG-2, the acronym for Motion Picture Expert Group. The Antitrust Division of the U.S. Department of Justice recently approved an arrangement that allows a single administrator to license MPEG-2 technology. These key technologies represent a market worth billions of dollars.

Commercial companies already are using these digital technologies. Direct satellite TV has a tiny satellite dish that receives the 0's and 1's via the airwaves and, through a decoding box, recreates the images and pixels on the TV screen. This takes about four million 0's and 1's per second. High definition TV (HDTV) is being developed by an alliance of companies and will need to generate about 20 million bits of 0's and 1's per second, said Dr. Anastassiou, resulting in larger TV screens that can show incredible details.

"It is like, in some magical way, using mathematical manipulations, these 0's and 1's determine that particular point is a dark red dot and the one next to it is less red,'' he explained. "Each 0 and 1 is interpreted, and, as long as the 0's and 1's are the same, the picture and sound will always be the same, with no deterioration.''

The digital technology is standardized world-wide, similar to the technology behind the facsimile machine. In effect, the fax machine employs compression and decompression technology that allows one fax machine to talk to another fax machine. It is better for all that there be only one standard for the process.

For digital technology, the MPEG-2 patent pool was created to set the standard. "The royalties to use the technology will be fairly small,'' said the professor, "so standard implementation will be possible without tremendous cost for the manufacturers.'' But the market is huge. "This technology will be in every PC and TV manufactured in the near future,'' he predicted.

Dr. Anastassiou is currently leading a new campus-wide center, the Columbia New Media Technology Center (CNMTC), aimed at developing the next generation of multimedia technology, in partnership with industry (both big and small local new media companies), government agencies and both the City and State of New York.

It is a collaborative effort involving the Schools of Engineering and Applied Science, Journalism, Business and Teachers College. He believes that Center faculty and students have excellent chances to develop many new, and equally important, inventions that will greatly benefit Columbia.