Aspect Ration?

[MiamiLoco]

Ok, mind my ignorance please, but here is my question. I recently got a 16:9 Television and I'm watching DVDs with Progressive Scan. Needless to say they look GREAT but here is my question. How come some anamorphic DVDs fill up the whole screen, while other anamorphic DVDs Still have the black bars on the bottom and top??

[1138]

Some movies are wider than 16x9. Some, like Star Wars, are 2.35:1. This is wider than 16x9 and so thought they still benefit from anamorphic, they still have some bars on the top and bottom.

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1138 - DVD File Forum Greeter
Ty Cobb wanted to play. None of us could stand the son-of-a-bitch when we were alive, so we told him to stick it!

[Blade]

When they were deciding on the new HDTV standard, they had to pick a new aspect ratio for the TV. They settled on 16:9 (which works out to 1.78:1).

Standard TV is in 4:3 (or 1.33:1)

Most movies are shot in 1.85:1.

1.78:1 (or 16:9) was considered a good compromise between these two aspect ratios.

When you watch a 1:85:1 movie, there are still black bars, but they are so small you can barely see them.

But when you watch a movie using a much larger aspect ratio like Titanic (which uses 2.35:1) then you are going to see black bars because of the much greater difference between 1.78:1 and 2.35:1.

The anamorphic process in regards to DVD does not determine the aspect ratio, but rather how many lines of picture resolution that the DVD is capable of displaying.

On non anamorphic DVDs, the black bars on widescreen movies are actually taking up lines of picture resolution on the DVD. On an anamorphic transfer, all of the lines of picture resolution are taken up by the movie. This increase of lines used for the movie results in a higher resolution picture.

If you view the unconverted image on an anamorphic disc the picture will look like everything is very skinny and tall. HDTVs are capable of taking this picture and strecthing out the image to its proper aspect ratio.

To view anamorphic video on a standard TV, your DVD player downconverts the anamorphic image by removing lines (thereby making the image less tall and skinny) until the image is shown in its proper aspect ratio.

Hope that helps more than it confuses!

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-David
My DVDs and HT

[This message has been edited by Blade (edited 06-02-2001).]

[Hendrik]

Blade: ...hey! you did very well! this business is rather confusing, and it is pretty difficult to describe it 'in twenty-five words or less' (which appears to be the maximum reading attention span for many people these days)...

MiamiLoco: ...also take a look here http://www.dvdweb.co.uk/information/anamorphic.htm - a nicely illustrated explanation of what's what - and why - in 'anamorphics'...

. . . . . .




[This message has been edited by Hendrik (edited 06-02-2001).]

[Joe Michaels]

This thread probably belongs in Hardware but since your question has been answered here's my 2 cents:
I hope people aren't buying 16:9 Tv's to eliminate the Black Bars.
They do reduce them on some movies but don't eliminate them entirely. The true purpose for 16:9 televisions to me is to get the full resolution from a DVD or widescreen presentation. If that is what you are after and can tolerate the bars and don;t want you 4:3 picture stretched, a standard sized TV with 16:9 mode is the way to go right now.

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Email: joe@dvdfile.com
READ Joe's home Theater & Entertainment Webzine -NOW Updated regularly!!!

[This message has been edited by Joe Michaels (edited 06-02-2001).]

[Eye]

Joe keyboarded:
I hope people aren't buying 16:9 Tv's to eliminate the Black Bars.

Ha! Funny you should type that.

I have a HDTV (Pro 700 Pioneer) and many people that I have over to watch DVDs turn to me and bitch: "I thought these new HDTV things were going to get rid of those stupid black bars!?!? Looks like you wasted your money."

I usually explain the whole "aspect ratio" gig and that usually mollifies the uprising, but yeah, I bet there's quite a large slice of the buying public that thinks HDTVs will "get rid" of "those black bars".



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..:: Eye | Moderator | eye@dvdfile.com | Picture of foot.


[This message has been edited by Eye (edited 06-02-2001).]

[1138]

"On an anamorphic transfer, all of the lines of picture resolution are taken up by the movie."

Sort of. On a 1.85 image, there's just the tiniest bit of black bars still but they're usually not visible due to overscan anyway. And of course, a 2.35 anamorphic image still does have some black bars taking up resolution.

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1138 - DVD File Forum Greeter
Ty Cobb wanted to play. None of us could stand the son-of-a-bitch when we were alive, so we told him to stick it!

[mahavishnu]

And another minor correction - 16x9 was considered a good compromised between 1.85:1 (American flat ratio) and 1.66:1 (European flat ratio). Television images weren't really the issue and, indeed, most TV is shot 16:9 nowadays.

[Blade]

Originally posted by 1138:
"On an anamorphic transfer, all of the lines of picture resolution are taken up by the movie."

Sort of. On a 1.85 image, there's just the tiniest bit of black bars still but they're usually not visible due to overscan anyway. And of course, a 2.35 anamorphic image still does have some black bars taking up resolution.

My understanding was that DVD had the ability to contain up to 480 (or 525, I forget) lines of resolution. Are you saying that 1:85 and 2:35 still use some of those lines to store picture information, or are you saying that a 16:9 TV will still display small black bars? Because I didn't think anamorphic DVDs still recorded black bars as part of the image, rather they were the result of the differences in the aspect ratio of the TV and the movie.

mahavishnu,

Really? Thank you for the correction. I did not know that. I always thought it was a compromise between the US's NTSC image standard and 1.85.

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-David
My DVDs and HT

[1138]

Yep. The problem is that a 16x9 Tv (or a 4x3 that does the squeeze trick) can only squeeze the image in one way. So that one way works just right for a 1.85 movie. Unfortunately, that means that a 2.35 movie will still have some black bars encoded in the picture area. Not as much as on a non anamorphic disc, but still some. Plus, you might start to get into some stair-stepping type problems by making a 2.35 image take up the whole picture.

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1138 - DVD File Forum Greeter
Ty Cobb wanted to play. None of us could stand the son-of-a-bitch when we were alive, so we told him to stick it!

[Blade]

Originally posted by 1138:
Yep. The problem is that a 16x9 Tv (or a 4x3 that does the squeeze trick) can only squeeze the image in one way. So that one way works just right for a 1.85 movie. Unfortunately, that means that a 2.35 movie will still have some black bars encoded in the picture area. Not as much as on a non anamorphic disc, but still some. Plus, you might start to get into some stair-stepping type problems by making a 2.35 image take up the whole picture.

I can see that. I've picked this stuff up from reading forums so I'm always having to modify my explanations as I run into people smarter than me.

Thanks!