The implications of this technology are quite staggering — and maybe even offer a lifeline for some small market stations.
Although news out of Los Alamos is usually rather muted, the Department of Energy's National Laboratory has been the subject of the news rather more often in the last year than wanted by the Department: From a suspected spy, with hard drives that should have been in the vault being found by the copier, to a devastating fire that was started by another Government department, the Lab has had its share of reporters' ink. Now a breakthrough in compression algorithms brings the Lab right into the broadcasting arena.
The Lab announced that an algorithm that was developed for image compression in underground nuclear testing is “capable of compressing a HDTV datastream to the point where the HDTV and analog signals can be broadcast over the same channel.” The implications of this technology are quite staggering — and maybe even offer a lifeline for some small market stations.
Instead of simulcasting analog and DTV on different channels the Lab is saying that you can broadcast your analog signal and then superimpose your DTV data with that signal. The result is certainly analogous to the conversion days of monochrome to NTSC — and it also has some limitations with a not-completely-perfect compression/decompression. But it would mean that an older analog receiver could take the signal as transmitted and think it is an NTSC signal; the digital receiver, with a software loop, would identify the digital data in the channel and extract it for reception and decoding. The losses in the digital signal are stated by the Lab to be about 20 percent of what would have been transmitted for a full HDTV signal stream. One of the problems, apparently, is that sync signals have to be left untouched so there is “dead” processing time during those intervals when a digital receiver would still be working away.
The exact operation of the algorithm isn't being discussed by the Lab but, apparently, the vestigial sideband is being employed with some sort of quadrature modulation that the analog receiver does not understand, and some letter-boxing space is also used which the analog receiver will see as gray instead of black.
The phrasing by the Los Alamos statements, using the algorithm's developer (George Nickel) as the mouthpiece, tends to suggest that the Lab thinks there would be the chance for the existing analog channel to have the DTV signal added to it; but it is obviously too late to stop the roll out of the new channels allocated to broadcasters. In any case, the older channels have been virtually presold, with their auction values already included in the Government's budget numbers. But even the notion that a broadcaster could still broadcast an analog signal — but on the new channel — is rather exciting. Those with analog receivers could simply retune to the new channel and the original channel could be closed down. As the market gets more used to DTV the costs of making the conversion to a digital receiver will tumble and, eventually, the analog service could be curtailed.
If this technology is going to be used, things need to be addressed quite smartly — before there are enough HDTV receivers or tuners sold to make a modification like this practically impossible. There also needs to be testing done very quickly to see whether this new format of signal allows the present channel allocations to still work; certainly it is unlikely that the scientists at Los Alamos have considered such mundane needs.
This is something that needs to be brought to the attention of the FCC as swiftly as possible. Instead of being in a punishing role for what it perceives are delay tactics by broadcasters, here is a chance for the Commission and broadcasters to both get what they need at the same time. And it makes possible that the switchover date for the standards can really be met — which will please the fiscal hearts in Congress as well.
But there is a snag to all this. The Lab considers this compression algorithm to be a commercial thing — something to license. That is simply impossible if there is to be universal adoption of such a standard, and I have a really hard time understanding how taxpayers can cough up for research such as this and not be allowed to reap the rewards of it. This is not like a NASA project that turns into a commercial product to be manufactured and sold by a company who is at risk with its funds in doing so; this should be a public standard. Then we will be able to say, at least once, that the Government was here to help us.
Paul McGoldrick is an industry consultant based on the West Coast.
