I’m a Philadelphia Eagles fan. I’m also a fan of “free”. So I was thrilled last week when the local ABC affiliate broadcast Monday Night Football over the air, because I don’t have cable or satellite service so I don’t get ESPN. The local station also broadcast the game in HDTV on their digital channel. Unfortunately, reports from a number of sources — including my friend Peter Putman — indicate that the over-the-air HDTV broadcast looked awful.
According to who you listen to, the problem was either that the station’s encoder was set incorrectly, or they were compressing the signal too much in order to use bandwidth for their two simulcast stations over the same digital channel. The fact is that local stations do compress HDTV signals; according to Peter, it can be as low as 8 Mb/sec which is far below the 19.38 MB/sec bandwidth available on an ATSC digital broadcast channel.
As Peter points out in a recent column for Insight Media, there is no equivalent to a “weights and measurement” enforcement agency for HDTV signals at this point. Broadcasters — over-the-air, cable, and satellite — can compress the signal all they want. The networks may try to establish some minimum standards for their programming, but enforcement remains an issue. As a result, it is important that consumers keep an eye on the quality of the transmissions they receive, and to complain when quality suffers as a result of signal compression.