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Posted by Captain Jinks on 12/11/05 01:42
Why don't you take your question up with several of the major hardware
manufacturers and see what they say rather than ask a forum full of
novices? Frankly it doesn't sound like you know enough on the subject to
review any equipment that I'd want to buy.
Jinks
In article <gmgraves-900EB5.07320808122005
@newsclstr02.news.prodigy.com>, gmgraves@pacbell.net says...
> I have a technical question about DVD aspect ratios. I'm not sure
> exactly how to phrase it so that it's clear, but I've come here because
> I can find nothing on the web that covers this.
>
> As you probably know, many HDTVs and HD-ready sets automatically assume
> that any time they see a component video input that has a 31.5KHz raster
> or higher, it's indicative of a high-definition program. This causes the
> TV to automatically apply the anamorphic stretch to the standard NTSC
> 4:3 frame to make it 16:9. In some sets, this anamorphic stretch is user
> defeatable, but in most, it is not.
>
> Most modern DVDs made from old TV shows, older, non-widscreen movies, or
> even DVDs that have the widescreen picture letterboxed rather than
> anamorphically squeezed, display the progressive picture output fine on
> sets where the anamorphic stretch can not be defeated, but other DVDs
> will display the progressive output as 16 X 9 when they should display
> it as 4:3 - with the inevitable distortion to the picture, of course.
>
> My question is simply this. Why is it that some 4:3 DVDs get stretched
> to 16:9 when played on a progressive player (irrespective of what one
> does with the "aspect ratio" controls in the set-up menu) while other
> 4:3 DVDs don't get stretched? Is there a 'bit' that can be set in the
> DVD headers at mastering which tells the player that the picture is 4:3,
> and when that bit isn't set, the player outputs the picture as 16:9? Or
> is the content of the discs that display correctly mastered
> anamorphically squeezed complete with side-bars? If the latter, how come
> they still look correct when played back on a normal NTSC monitor using
> composite or S-VHS inputs?
>
> I need to know this because I review a lot of DVD players for an on-line
> video magazine and I've not seen ONE player that will allow some of
> these 4:3 DVDs to display properly when output progressively or
> up-sampled and I'm at a loss to explain exactly why this happens.
>
> Thank you in advance for any insight into this phenomenon that you can
> give me.
>
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