HD Service

(From The Yahoo Avid User's Group)

When cable systems first rolled out their HD service its quality was quite good. Now, as they've added HD channels it appears they've begun cranking up the compression.

The worst was the Patriots/Broncos game a a few weeks ago on CBS. When a field goal or point after attempt was kicked and the camera tilted up and down rather quickly to follow the path of the ball, the fans behind the goal posts literally turned into a pixelated mass of squares. It was truly awful.

Oddly it varies. Sometimes CBS sucks, sometimes FOX, sometimes NBC. Rarely do all three look like crap. Never does ESPN or HBO.

I have an antenna and can pick up WGBH (PBS) and WBZ (CBS) off air quite well. I live 30 miles from the transmitters, so the others take some monkeying. I switched to the Pats broadcast and it looked beautiful.

I watched a transmission demo at NAB years ago -- don't recall the company -- but they were touting their "on demand" bandwidth multiplexing.

Basically, the pipe's "X" big -- and there are "Y" channels in the pipe. If channel "Y5" hits a scene (football crowd pan) where it needs more than it's allocated bandwidth, it can momentarily "borrow" it from a channel -- channels (Y16/Y21) -- that may not be using all their bandwidth at the moment (dark static scene in a film).

It made perfect sense at the time -- but it wasn't hard to figure out that between a baseball game and a football game something in the multiplexed stream was going to suffer heavily.