Ed wrote:
> Let's say I am watching a football game in hi-def, on my 32' LCD TV. I
> don't really know if it's 720 or 1080 - the point is, the image fills
> every pixel of the screen at 16:9, and it looks fantastic. Literally,
> you can see every blade of grass. I am in video heaven.
>
> Then, I switch over to PBS and watch, oh, Nature or Masterpiece or
> something like that. I know PBS is broadcasting in hi-def but the
> image is often letter-boxed 16:9, with several inches of black space
> all around. Sure, I can expand it in some fa****on using the TV aspect
> controls but then it either is distorted or else has a certain
> fuzziness that detracts from the quality.
>
> It's not like this all the time - I think some PBS programs really are
> full-screen hi-def, like I would have expected. But it seems like the
> ones I really want to see are smaller than the available space.
>
> What is going on here? Why isn't PBS hi-def like football-game hi-def?
> I read about some PBS stations doing some sort of bandwidth-saving
> compromise on their hi-def broadcasts - is this what I am seeing?
>
> Thanks,
> Ed
The letterboxed program is likely a SD program. A number of PBS
programs have been shot in widescreen SD, not HD. some PBS stations may
zoom it on the HD channels, others will show it letterboxed. Personally
I prefer them to zoom it if it is a 16:9 SD program. This has little to
do with bandwidth, the PBS station is just playing a SD version.
You should also realize that not all true HD will fill the 16:9
screen. Movies have been filmed in many aspect ratios from 1.37:1
Academy Ratio (common up to the early to mid-1950s), 1:66.1, 1.85:1,
2.0:1, 2.20;1, 2.39:1 (cinemascope), and a few in the 50s & 60s shot at
superwide 2.76:1 (Ben-Hur is the best known example). Except for 1.85:1
which is close enough to 1.78:1 that they is usually cropped a little,
all of these will be letterboxed or pillar boxed if they maintain the
Original Aspect Ratio when showing them in HD on a HD channel.
Same goes for older TV shows shot on film which were framed for 4:3.
There is now a respectable list of TV shows going back to the 1950s that
have been re-telecined to HD and will likely show up in syndication or
on expensive Blu-Ray box sets in the next several years. These will not
fill the 16:9 screen unless they crop them (and many unfortunately will
be), but will be HD.
HD does not always equal 16:9. On the other hand, 16:9 framing does
not always mean HD, it could be a widescreen SD program. And this is a
simplified answer.
Alan F
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