Quote:
Originally Posted by Jeffhs
... Could it be the FCC has approved some sort of automatic station ID system, in which the identification information is actually in the vertical blanking interval and so is invisible to the viewers?  |
There's no such thing as a vertical blanking interval in digital TV broadcasts; the virtual channel ID is carried in metadata - without it, the TV set could only identify the RF channel it's tuned to, and the broadcasters definitely want their virtual channel number identified to the viewer instead. The requirement to identify with an FCC approved virtual channel became regulation with the adoption of the ATSC standard by the FCC. There have been a few cases where the FCC has had to rule on virtual channel number disputes between broadcasters, but there are written regulations in place about how they get assigned that take care of most cases. Originally, most stations were simply assigned their original analog RF channel number (which they had branded themselves with), but it got more complex with spectrum auctions and repacking.
I don't know or recall if the rules requiring ID as part of the video and audio was dropped with the switch to digital.