Why am I seeing double pillarboxes on some TV channels?
For awhile now, I've noticed some subchannels showing the 4:3 content with an extra set of pillarboxes. My TV puts light gray bars up when it sees 4:3 content. But on some channels, I see narrower black ones inside the gray ones. I'm pretty sure these extra pillarboxes are being transmitted as part of the 4:3 content (the light gray pillarboxes didn't change in width). Note: I'm watching over the air TV (no cable).
Here's a diagram of what I'm seeing (white center part has TV show):
At first, I thought maybe the content was actually narrower than 4:3 (old movies), but that's not it because some subchannels are showing 70s TV shows and these are definitely 4:3 content.
Maybe these channels are implementing some sort of newish "anamorphic widescreen" capability so someday they can air 16:9 content on a subchannel meant for 4:3? (I'm guessing. My TV is an older HDTV, so if anything was added in the last 10 years or so, it couldn't automatically handle it).
Anyone know what's going on here? Knowing what it is could help me correct for it.
UPDATE: I found a subchannel that had bars that looked like old fashioned wallpaper (instead of black). Also, I noticed the widths of the bars vary from channel to channel (some are pretty thin, the ones with the "wallpaper" look are pretty wide).
Best Answer
OK, no one knows, so I did it the hard way. I watched various channels when my TV was told to show 4:3 content in 4:3 (not stretched in any way) and looked for known round objects (car wheels, clocks, et). I found them to be squeezed. I recorded a channel that had the double pillarboxes on my HTPC and when I played it back, the extra pillarboxes were gone. Somehow my HDTV tuner/player knew the image was being squeezed and automatically stretched it. I did a lot of searching and found there is a bit that tells the TV the image is "squeezed", much like an anamorphic widescreen DVD: link one, link two. The second link is an addendum to the original standard. That probably explains why my TV doesn't auto stretch and no one else sees this--my TV is too old.
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Why are some channels not full screen?
TV is not displaying the channel content full screen or shows black bars. This indicates that the program is being broadcast in a different format then your TV is programmed to display. It often occurs when the show is broadcast in Standard Definition (SD) on and you have a High Definition (HD) TV.What is the correct aspect ratio for TV?
16:9 works great for TVs, since that is the aspect ratio used by the majority of today's TV shows, but unfortunately, most movies are made using the cinema standard, which is 21:9. 21:9 is much wider, so parts of the screen need to be filled with black bars above and below the image in order to fit most TVs.Why is letterbox on widescreen TV?
The rise of the DVD format in the late 1990s started to educate people about how theatrical movies often came in different shapes that required letterboxing to preserve their Original Aspect Ratios, and the transition from standard definition to HDTV moved everyone away from the boxy 4:3 TVs of old to a wider standard.What aspect ratio are old TV shows?
Old TV shows generally have an aspect ratio of 4x3. In order to fit them on your wider screen, 16x9 HDTV, something has to give. You can't fit a square peg in a rectangular hole, so to speak.How To Rescan Channels On A Samsung TV
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