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Technology Stocks : C-Cube -- Ignore unavailable to you. Want to Upgrade?

To: J Fieb who wrote (40118)	4/24/1999 9:38:00 AM
From: John Rieman	Respond to of 50808

The JVC decoder sounds like C-Cube silicon, JVC microcode. What's happening in MPEG? A Divicom author............... broadcastengineering.com Future MPEG technology Question: What new MPEG technologies are coming and how will they affect and interoperate with the equipment purchased today. Should equipment purchases be delayed until the new technology is available? By Eric Norton Let's take a quick tour of what is happening in the MPEG world: • MPEG audio layer III (a.k.a MP3) is a format for compressing audio at extremely low bit rates. Of course, the bandwidth (and sound quality) is correspondingly reduced. MP3's real application is the Internet, and the demands of the broadcast community will require them to stick with MPEG layer II or Dolby Digital (AC-3). • MPEG AAC (Advanced Audio Coding) is a nonbackwards-compatible multichannel audio format. It has been adopted by the Japanese market, but as mentioned ATSC broadcasters will use Dolby Digital. Non-ATSC MPEG-2 broadcasters have a choice of Dolby Digital or MPEG layer II, and that choice is usually dictated by what the set top box supports. • MPEG-4 is intended for multimedia applications (ah, that Internet again) at very low bit rates. There is no immediate application in the broadcast world, except perhaps for the inclusion of MPEG-4 data into an MPEG-2 transport stream for delivering web-browsing material to set top boxes. The video quality of MPEG-4 would not be acceptable by broadcast standards, as it wasn't designed for broadcast. • MPEG-7 (formally called the Multimedia Content Description Interface) is a scheme for making video and audio databases searchable. Thus a text description accompanies the video and audio. While this might be very interesting to the news producer searching for specific material, or for the web browser, it has no immediate effect on broadcasting to the home. So while exciting work continues in many areas of video, audio, and data compression, there are no revolutionary MPEG developments for broadcasters in the near future. Of course, I am considering high-definition (main profile @ high level) to be here and now, not in the future. So what should broadcasters be looking for? • A strong encoding core. Let's remember that MPEG is a decoding specification. It says what is legal, but doesn't say how to encode. Thus there is a wide variance of encoder quality on the market today. While most encoders look the same at 8Mb/s, at 2Mb/s there is a considerable difference in video quality. Be sure to pick an encoder that provides good pictures at your desired bit rate, resolution, and filtering. • Efficient use of bandwidth. If you have 19.39Mb/s, you might as well use it. Does your encoder vendor support statistical multiplexing of channels so that you are maximizing your return on bandwidth? Can you also add data to the transport stream to support datacasting applications such as web browsing? • An upgradable architecture. MPEG encoding is very complex. This is mainly because our eyes are very complex. The way we notice some noise but not others, the way we are more sensitive to horizontal motion than to vertical motion, the way we are generally more comfortable with soft pictures than motion artifacts, and a whole list of other psycho-optical relationships make the eye a very demanding customer. As work continues in understanding how the eye responds to say, scene transitions, work also continues in making the MPEG compression algorithms more efficient. Be sure to pick an encoder that allows you to seamlessly upgrade the encoding algorithm in the future. • A scalable architecture. Supporting high-definition and standard definition in the same transport stream and allowing seamless switching between the two will ease the burden on the operator and deliver a much more enjoyable end product to the consumer. Eric Norton is group manager of product marketing for Divicom, Milpitas, CA.