HD Resolution Question

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giantpinkbunnyhead

Diamond Member
Dec 7, 2005
3,251
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OK, I just realized something and it's bugging me.

My TV (Westy 42") has a native resolution of 1920x1080. Which I figure is nice, since HD movies are essentially 1080i/p. So, my TV should have the same number of pixel rows as there are lines of resolution on an HD/Blu Ray disc.

Yet, when I watch an HD movie, I have small black bars on the top and bottom. So now, I don't have all 1080 lines showing a picture. Where are those missing lines going?? If HD is 1080... shouldn't I have all 1080 lines? Is the image being scaled down? Is there something I can/should do about this, or is it "just the way it is"? I'm just not understanding something here and not knowing what it is I'm not getting is bugging me.
 
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giantpinkbunnyhead

Diamond Member
Dec 7, 2005
3,251
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Yes, I understand the aspect ratio is a factor here. But this doesn't answer my question. What is happening to the missing lines? Obviously... my TV isn't displaying 1080 lines of data if I have black bars. But the movie is still coded in 1080. Is my image being scaled down so that all 1080 lines fit onto the reduced "screen size"? Or is the top/bottom of the image simply being cropped and discarded? I'm just curious what action is occurring that results in a 1080-line signal, being displayed on less than 1080 lines on my screen.

This really is more of a curiosity than a complaint. I just want to understand this mismatch better.
 
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darkswordsman17

Lifer
Mar 11, 2004
23,444
5,852
146
Those lines are just blacked out. Er, that doesn't sound right. That is to say since there is no content in those lines that there is nothing to display there. Its not taking a 1080 image and just cutting parts off. It is formatting itself to the resolution. Since its over-wide, it will therefore use up the horizontal pixel space before it uses up the vertical pixel space.
 
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krotchy

Golden Member
Mar 29, 2006
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I suppose you could say you are missing some lines, but its not affecting detail.

A 1920x1080 movie with a 2.35:1 aspect ratio would be encoded at 1920x817 roughly. However if you were you watch it on a 720p screen its 1280x544. So your 1080p screen is still showing the full horizontal detail of the movie and giving it to you as tall as it can with maximum horizontal detail.
 
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cubby1223

Lifer
May 24, 2004
13,518
42
86
Originally posted by: giantpinkbunnyhead
Yes, I understand the aspect ratio is a factor here. But this doesn't answer my question. What is happening to the missing lines? Obviously... my TV isn't displaying 1080 lines of data if I have black bars. But the movie is still coded in 1080. Is my image being scaled down so that all 1080 lines fit onto the reduced "screen size"? Or is the top/bottom of the image simply being cropped and discarded? I'm just curious what action is occurring that results in a 1080-line signal, being displayed on less than 1080 lines on my screen.

This really is more of a curiosity than a complaint. I just want to understand this mismatch better.
Click to expand...
Watch a widescreen dvd then the fullscreen dvd version of the same movie on your old 4:3 crt. Ask yourself where are the missing lines on the widescreen dvd, then also since you've watched both versions, also ask yourself which movie is actually "missing" something.
 
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Auric

Diamond Member
Oct 11, 1999
9,591
2
71
Not another one of these threads :p

HDTV sports an aspect ratio of 1.78:1 -a compromise betwixt film formats of 1.37/1.33 (also SDTV) and 1.85. Whereas the widescreen film formats are 2.35 (olde timey) and 2.39 (contemporary). That is unpossible on disc formats so 2.40:1 is used. Ergo, 1920x800. Ergoplus, matting of 140 pixels (x2).

With correct configuration, 1:1 pixel mapping results in a precise image with nothing lost. "Failing" to use the maximum available area is merely psychological since HDTV has been promoted as cutting-edge whizbang supermarvyfab... and "widescreen", which it may be in relation to SDTV but of course not film.

So this must be taken into consideration when choo-choo choosing a display for such content. Since, for example, given a 42" model's height of about 524-ish (?) mm, only 388 will be utilized, resulting in a significantly smaller image than possibly expected when those expectations are based solely upon TV/video content.

Anyhoo, open this test pattern in a video player (such as MPC) to confirm an accurate image. Use the step patterns here for colour, contrast, &c. calibration too.
 
prism

prism

Senior member
Oct 23, 2004
967
0
0
Originally posted by: montypythizzle
Originally posted by: Tiamat
Originally posted by: montypythizzle
Originally posted by: PurdueRy
The other lines of resolution are drawing the black bars.
Click to expand...

Isn't he going to get burn-in from those black bars? :p
Click to expand...

Only on plasma tv :p
Click to expand...

Even with Monster cables?? :shocked:
Click to expand...

Of course not if you're using Monster Cables. Plus, if you're using them, you automatically get free premium channels from your dish/cable provider, and a free lifetime pass to the Playboy Mansion.
 
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Auric

Diamond Member
Oct 11, 1999
9,591
2
71
Thinking aboot this s'more... consider Ben-Hur which sports an aspect ratio of 2.76:1 (oh yeah, now we're talking real widescreen!). Watching that on a 42" HDTV is akin to Citizen Kane (1.37:1) on a 21" SDTV, height-wise (approximately 330mm), so delivers the same "experience", resolution aside. However, the importance of resolution diminishes with size and that's getting rather small.
 
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giantpinkbunnyhead

Diamond Member
Dec 7, 2005
3,251
1
0
Originally posted by: krotchy
I suppose you could say you are missing some lines, but its not affecting detail.

A 1920x1080 movie with a 2.35:1 aspect ratio would be encoded at 1920x817 roughly. However if you were you watch it on a 720p screen its 1280x544. So your 1080p screen is still showing the full horizontal detail of the movie and giving it to you as tall as it can with maximum horizontal detail.
Click to expand...

Ahhh... I think I get it now... so, even though the movie itself is labelled 1080i/p... doesn't mean it's encoded with 1080 lines. So I am still getting line-by-line from the disc to the TV; but the difference is that the disc doesn't have 1080 lines of resolution on it; only 817 (in your example). So, the image isn't being scaled OR cropped after all... it was in it's final size all along. Thanks for the explanation!
 
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montypythizzle

Diamond Member
Nov 12, 2006
3,698
0
71
Originally posted by: Prism
Originally posted by: montypythizzle
Originally posted by: Tiamat
Originally posted by: montypythizzle
Originally posted by: PurdueRy
The other lines of resolution are drawing the black bars.
Click to expand...

Isn't he going to get burn-in from those black bars? :p
Click to expand...

Only on plasma tv :p
Click to expand...

Even with Monster cables?? :shocked:
Click to expand...

Of course not if you're using Monster Cables. Plus, if you're using them, you automatically get free premium channels from your dish/cable provider, and a free lifetime pass to the Playboy Mansion.
Click to expand...

Yeah, good to hear, I am glad I used only the finest 24K plated connector TOSLINK cables.
 
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