Was watching Seinfeld on CW and it was in hi-def. It filled my TV screen and looked as clear as the commercials. The OTA broadcasts this channel in 720p. So how is it that these old shows -- and even older -- can now be shown in hi-def? Is the source material hi-def but downgraded back in the day for OTA CRT low-res viewing? Old film and video tape, by nature, has the fidelity to be viewed in hi-def today?? Were old shows filmed/recorded in 4:3 or 16:9? If the former then I assume they crop the image to fit the latter?