Electronic Design

Standards Around The House

The typical entertainment center is more than TV nowadays. And all of these options means a variety of video standards.

In the U.S., broadcasting companies face several challenges stemming from Congress' requirement for across-the-board DTV signaling by 2009 in both standard-definition television (SDTV) and HDTV. Greater obstacles await HDTV-capable television manufacturers, as they try to overcome three particularly thorny problems.

The first involves manufacturing TV sets that can support multiple digital broadcast standards. This challenge is courtesy of the nations that can't seem to agree on a single broadcast standard. In the U.S., there is the Advanced Television Systems Committee (ATSC), which has also been adopted by South Korea, Canada, Mexico, and other countries.

Then, there is the Integrated Services Digital Broadcasting (ISDB), developed in Japan and adopted in other countries like Brazil. Most of Europe is standardized on digital video broadcasting (DVB). The phase-alternating line (PAL) is yet another standard adopted by much of the rest of the world. And just to be different, China is in the midst of creating a new digital multimedia broadcast system (DMB), which is based on other systems.

Meanwhile, designers in Japan are proposing a new standard named Ultra High Definition Video, which is 16 times the resolution of HDTV and requires about 1 Tbyte for every five minutes when uncompressed. Given all of these ?standards,? developing a TV that can handle the various resolutions, bit rates, frames per second (fps), codecs, and video-processing techniques can be a real nightmare.

The second challenge involves moving the set-top box features, decoders, and video-processing algorithms into the HDTV, thus removing the need for a set-top box altogether. This push will create interesting future choices for consumers: do they want an all-in-one solution or a set-top box with all the latest bells and whistles? Finally, the third challenge will be to continue to drive the cost of HDTVs down, and provide affordable solutions to developing nations.

Mobile Video & Personal Media Players
Personal media players come in many shapes and sizes, and can generally play many different audio and video formats. They can be purchased with a wide variety of features and they're priced accordingly. Other mobile devices, such as cell phones, also are starting to become video-capable.

The primary challenge with mobile devices and personal media players is in maximizing the bang for the buck with respect to resolution, speed, and CPU usage while limiting power consumption as much as possible. Therefore, mobile devices must be designed with ICs that use minimal run and standby current, yet maximize the capability of their inherent small displays.

IPTV delivers DTV and video on demand (VOD) via the Internet Protocol over a broadband network connection such as DSL. Its main challenge in IPTV really lies in what performance a designer can squeeze out of speed- and bandwidth-limited Internet connections. Most people must deal with less than 1 Mbit/s. But regardless of the Internet connection speed, unless you have a fiber-optic connection, you can forget about using the advanced profiles of the H.264 or VC-1 codecs. But you can still get reasonable bit rates, resolutions, and frame rates to make the IPTV experience worthwhile.

Another IPTV challenge involves the real-time transfer requirement. Typically, consumers download a video and watch it soon after, but this doesn't work when you're trying to watch a live sporting event. As a result, service providers must encode real-time streams and avoid network congestion.

The final challenge with IPTV is handling the stream bursts associated with streaming video. This requires a reasonable stream buffer on the receiver to prevent over-run and under-run of the buffer.

Set-Top Boxes
Set-top boxes connect TVs to some external television source, which can be an Internet connection via DSL, cable, satellite, and even terrestrial signals from an antenna connection. Before 2000, they only received signals. Now, they may include a digital video recorder, a DSP chip that may be upgraded with the latest codec, video-processing features, and integrated IPTV functionality.

Set-top-box manufacturers face competition from HDTV manufacturers who now integrate set-top-box functionality into the TV. Advantages of integration revolve around the video processing, which can be tweaked for a given TV to better use its integrated features. As a countermeasure, set-top-box OEMs offer even better video processing and more integration.

HD DVD & Blu-Ray
HD DVD and Blu-ray, the latest optical disc technologies, both use a blue laser with a 405-nm wavelength to read and write data. Traditional DVDs use a 650-nm red laser. With the shorter wavelength, substantially more data can be written to the same optical disc size.

Although Blu-ray and HD DVD both use a blue laser, Blu-ray can hold about 10 more gigabytes of data (25 Gbytes total) per layer, which translates to 50 Gbytes total per disc. With those 50 Gbytes, Blu-ray discs can hold up to nine hours of HD-encoded video and up to 23 hours of SD-encoded video.

Before either technology can take off, though, consumers must choose between them. And they have to give up their old DVD players for a significantly more expensive technology. Most consumers likely will wait for a clear leader to emerge and for costs to come down. Movies on demand available from broadcasters in the HD format aren't too far off either, so expect some competition there as well.

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