Coming Soon To A Set-Top Box Near You: MPEG-4

[Gregg Lengling]

DirecTV and LG Electronics made a joint announcement that the Korean electronics giant has begun production of the first DirecTV set-top boxes that will decode signals encoded using MPEG-4 video compression. The boxes will be sold under the DirecTV brand name and will empower a massive increase in DirecTV's lineup of HDTV channels that is scheduled to begin this fall.

DirecTV plans to offer local network affiliate broadcasts in HD in major US markets later this year, but that's just the icing on the cake. By 2007 the satellite provider, which currently boasts nearly 15 million subscribers, plans to offer a total of 1,500 HD local broadcast channels and more than 150 national channels in HD. In order to squeeze in so many new HD channels a much more efficient and higher quality video compression scheme than the current MPEG-2 standard was required, hence the decision to go with MPEG-4. Given that demand for HD is expected to grow (if not boom) over the nextt few years, it's expected that other cable and satellite providers will follow suit and begin using MPEG-4 compression in the future as well.

MPEG-4 and Advanced Video Coding H.264 are essentially synonymous, and the latter is a mandatory codec for both Blu-ray Disc and HD DVD. Its proponents claim that it can generate video quality identical to current MPEG-2 compressed HD signals using just half the bandwidth.

Demonstrations I've witnessed of 1080p HD video at just 12Mbps were impressive, if somewhat inconclusive due to the typical constraints of viewing on unfamiliar display and playback hardware. 12Mbps is barely more than the maximum transfer rate of the current DVD standard and well south of data rates typically used now for MPEG-2 encoded HD signals, which are often in the neighborhood of 20Mbps. While there are no guarantees that the data rates DirecTV will employ will be as high as 12Mbps, it should also be noted that most existing HD source material is 720p or 1080i, which is not as bandwidth hungry as 1080p.

Some of the features of the new DirecTV set-top box were also given. Most notable was the HDCP-compatible HDMI output with simultaneous composite and component output, as well as a Linux-based operating system and USB port. Mention was also made of a fifth-generation "VSB" chipset, which means Over-The-Air HD signals can be received from an antenna and decoded with the new box as well.

The box will be backward compatible with MPEG-2 broadcasts, but note that an MPEG-4 compatible box will be required to view DirecTV's new MPEG-4 encoded HD channels. No word at this time as to whether any of DirecTV's existing set-top boxes are upgradeable in the field, or what, if any, concessions DirecTV will make to current customers (like me) who are owners of their current, non-MPEG-4 HDTV set-top boxes and DVRs.