Aspect Ratio

Technically-oriented discussion of classic films on everything from 35mm to Blu-Ray
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gkoch

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Aspect Ratio

PostTue Aug 12, 2008 2:27 am

Back when I bought my first DVD player one of my first Netflix rentals was a silent movie that had a black border around the frame. Wow, i thought, DVDs are gonna show me the entire picture! AND have commentary.

But i never saw one like that again.

So what are the reasons for not seeing the entire image on even the latest restorations?
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Jack Theakston

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PostTue Aug 12, 2008 6:06 pm

The technique you're talking about is known as "windowboxing." Because cathode-ray tube sets are not locked into one vertical or horizontal hold, there's usually an amount of information that gets cut off (called overscan). By bordering the picture with a little bit of black, this keeps the larger picture intact.

However, with the increasing number of non-CRT sets taking over the market, there's no reason for this anymore. Plasma and LCD sets are more rigid in their accuracy and adjustments. Windowboxing will be unnecessary in the next five or so years.
J. Theakston
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Harlett O'Dowd

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PostWed Aug 13, 2008 7:14 am

Jack Theakston wrote:The technique you're talking about is known as "windowboxing." Because cathode-ray tube sets are not locked into one vertical or horizontal hold, there's usually an amount of information that gets cut off (called overscan). By bordering the picture with a little bit of black, this keeps the larger picture intact.

However, with the increasing number of non-CRT sets taking over the market, there's no reason for this anymore. Plasma and LCD sets are more rigid in their accuracy and adjustments. Windowboxing will be unnecessary in the next five or so years.


but are the prints available now going to play in true "full-screen" on a non-CRT TV. For example, if I ever again sit through the TCM print of Dixiana, will I be able to see Bill Robinson's feet?
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Richard P. May

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PostWed Aug 13, 2008 9:19 am

I don't find any problem showing 1:37 images on a wide screen TV. It is just necessary to be sure the TV is set correctly.
If I would blow up the image to fill the screen horizontally, it would certainly cut off the top and bottom of the full-frame image. There is a setting, however, that preserves the way the film was mastered.
Different makes of TV might, of course, have different settings.
Dick May
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Jack Theakston

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PostThu Aug 14, 2008 6:32 pm

As Dick says-- so long as you set your TV set accordingly (normal, pillarboxed rather than stretched or cropped), there should be no problem.
J. Theakston
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Dustin

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PostFri Aug 15, 2008 1:07 am

Of course, there still is an overscan even on non-CRT TVs. It's nowhere near as large, but some of the picture will still be cropped.

On a CRT TV, I assume around 20px will be lost on either side. On DLP projectors and LCD panels, I assume between 5 and 10px. DLP crops the least in my experience.

You can watch it on a monitor designed for computer use (which has no overscan even if it is CRT) and see the whole picture. One caveat, some really cheap DVD players don't bother to decode the extreme edges of the picture, assuming they won't be visible anyway, but mid-range and up DVD players and every VCR I've ever seen will send the whole picture.


Some TVs (especially CRT HDTVs), even when set to pillarbox, will crop the image to 14:9. There's not much you can do in that case, unless your DVD player offers aspect ratio options. If it does, you can set the TV to stretch and the DVD player to pillarbox and it should result in a 4:3 image.

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