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Author Topic: Theater View not accounting for properly calibrated TV overscan.  (Read 7016 times)

lalittle

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Regarding the problem where Theater View does not account for the normal amount of overscan on TVs, Matt said:

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This is the job of the video card / TV.

I use Theater View via S-Video to a TV all the time, and with my ATI card, you can configure it to make it fit perfectly.

Check for new drivers or settings in your TV.

This is actually not the proper way to deal with this situation.  TV monitors are made by design to crop a little off the edges of the image in order to eliminate any distortion that occurs at the edges of the images it displays.  Computers and computer monitors, on the other hand, don't do this -- they use the ENTIRE frame right up to the edges.  Because of this, some graphics cards allow you to adjust the amount of overscan in the output, giving you the ability to adjust the image to that you can see the entire desktop on a TV monitor.

Unfortunately, not all graphics cards allow you to do this.  Nvidia cards, for example, only allow 2 settings -- overscan and underscan.  When you select underscan, it actually scans the image well in from the outside edges of the frame, leaving a black border around the edges that is literally not being scanned on at all.  This is actually bad for the tube since the edges receive uneven wear over time.  This is also not the correct way to view NTSC content which was created with overscan in mind -- i.e. content is specifically created with the knowlegde that the edges (about 5% on all edges) won't be seen.  In other words, if you have your TV set up to "properly" display DVDs, it WILL cut into the information in MC's Theater View mode.

My system, which is used for video editing, has the overscan properly calibrated for standard NTSC output from the computer -- the amount of overscan it uses is "correct."   On this monitor, the edges of the Theater View screen do not fit withing the visible frame.  It would not make sense to adjust the TV to accomodate Media Center since the TV is already "properly" calibrated with the "correct" amount of overscan, and I don't want to use underscan for reasons already stated.  MC Theater View is therefore the "odd man out" -- it is designed to be used on an NTSC device, yet the image breaks the standard rules for keeping the image in the "safe" area of the screen where ALL TVs will display it properly.

Since Theater View is specifically designed to display on a TV and not a computer monitor, why not design the layout with this in mind, and keep the information within the official "safe" area of the screen.  This will ensure that Theater View works properly on ALL sets with ALL graphics cards.

Thanks,

Larry
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lalittle

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #1 on: April 15, 2004, 03:20:57 pm »

Just to add to this, I would recommend taking a look at the menu screens from some mainstream DVDs on an underscanned monitor to see the typical distance they keep the "necessary" parts of the image in from the edges.  I've yet to see a DVD menu that had portions of the selection items cut off by the overscan.  I'd guess that somewhere around 5% to 7% in from the edges work for Theater View.

Also, a google search for "action safe" and "title safe" should bring up some examples of the official frame lines for these areas.

Larry
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Matt

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #2 on: April 15, 2004, 04:26:45 pm »

The Theater View skins all use basically the same main.xml file.

However, Theater View's layout is quite flexible, and is simple to tune by editing main.xml with a text editor.

Maybe you could make a modified version of a skin that deals well with overscan.  We'll include it with the build if it works well.

Thanks Larry.
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Matt Ashland, JRiver Media Center

loraan

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #3 on: April 15, 2004, 04:45:21 pm »

had portions of the selection items cut off by the overscan.  I'd guess that somewhere around 5% to 7% in from the edges work for Theater View.

"Safe Action" is 5%, "Safe Title" is 10%.

My $0.02: my TV has about 3-4% overscan all around. But I've used PowerStrip to configure the video timings of my graphics card so that it underscans just exactly enough to fit on the screen with zero over/underscan. I recommend that anybody who's having the problem discussed on this thread check out PowerStrip. It's got a bit of a learning curve, but it's totally awesome once you get it working right. Custom resolutions, custom display timings, you name it...

One caveat: Powerstrip works best with ATI cards. Many other cards don't allow the full range of custom resolutions and timings.
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lalittle

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #4 on: April 15, 2004, 08:44:19 pm »

The Theater View skins all use basically the same main.xml file.

However, Theater View's layout is quite flexible, and is simple to tune by editing main.xml with a text editor.

Maybe you could make a modified version of a skin that deals well with overscan.  We'll include it with the build if it works well.

Thanks Larry.

I'll look into this and see what I can come up with.

Thanks,

Larry
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lalittle

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #5 on: April 15, 2004, 08:58:41 pm »

Matt,

Do you have any information that might help me decode the settings in that file?

For example, is there a "global" margin setting, or do I have to manually edit each item?

loraan,

I wouldn't want to use powerstrip even if it DID work with my graphics card since everything is already set up for standard NTSC video display on the TV monitor.  It wouldn't make sense to change the settings just to use Media Center.  It would make more sense to adjust the Theater View so that it worked correctly with the "correct" monitor settings.

Thanks again,

Larry
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lalittle

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #6 on: April 15, 2004, 09:23:44 pm »

Matt,

I'm getting the hang of this.  After a little trial and error it looks like I should be able to achieve what I'm trying for.  How do I send you the file when I'm done?

Larry
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Scarpad

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #7 on: April 16, 2004, 06:46:35 am »

Lalittle any chance you could email me this file as well? I'll give it a go on my set..

scarpad@comcast.net
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loraan

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #8 on: April 16, 2004, 10:26:01 am »

I wouldn't want to use powerstrip even if it DID work with my graphics card since everything is already set up for standard NTSC video display on the TV monitor.  It wouldn't make sense to change the settings just to use Media Center.  It would make more sense to adjust the Theater View so that it worked correctly with the "correct" monitor settings.

I guess I have a different perspective on it. NTSC signals are intended to be overscanned, but computer screens aren't. If I'm displaying a computer screen on a TV, I'd rather adjust the computer screen so that it doesn't overscan. But I use my HTPC for desktop computing a significant amount of time. If the TV were a secondary display that only played movies (in other words, if I had a dedicated monitor for my desktop), I would probably prefer to leave it overscanned.
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lalittle

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #9 on: April 16, 2004, 03:48:42 pm »

I guess I have a different perspective on it. NTSC signals are intended to be overscanned, but computer screens aren't. If I'm displaying a computer screen on a TV, I'd rather adjust the computer screen so that it doesn't overscan.

My take on it is the other way around -- that is, you AREN'T displaying a "computer screen" on the TV, but rather you're displaying an NTSC image that's simply generated by the computer.  The Theater View screen is specifically designed to be viewed on a TV screen, so it should follow the same rules as OTHER NTSC sources rather than using a set of rules that applies to a different type of monitor.  If you're using the computer to generate signals that would normally be viewed on a TV screen -- i.e. DVDs or TV stations -- then you should be using normal overscan settings since these signals are designed to be viewed on a monitor with overscan.

It doesn't make sense to have Theater View following "computer screen" rules when it's designed to be displayed on a TV screen.  If you adjusted the monitor for the "current" Theater View screen, then DVD and TV images will be incorrectly displayed.

Larry

Scarpad -- I'll send you what I have so far.
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Nolonemo

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #10 on: April 16, 2004, 04:44:07 pm »

I don't get the point of this discussion at all.  My video card has a TV out, and included in the driver/control center software is the ability to adjust the image size sent thru the video out to account for the TV overscan.  That doesn't affect the image display on the monitor.  Don't all TV out cards have this feature in their software?

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lalittle

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #11 on: April 16, 2004, 05:14:00 pm »

I don't get the point of this discussion at all.  My video card has a TV out, and included in the driver/control center software is the ability to adjust the image size sent thru the video out to account for the TV overscan.  That doesn't affect the image display on the monitor.  Don't all TV out cards have this feature in their software?

I'm not clear what it is you don't get.  In a nutshell, TV monitors are simply not designed to show the entire image being broadcast to it.  They "overscan" the image so that the edges are slightly cut off.  If you adjust your graphics card to compensate for this fact, then any type of NTSC output designed for display on a TV monitor with be displayed INCORRECTLY on your TV -- you'll be seeing the edges of the image that are supposed to be cut off due to the TV's overscanning.

Since the Theater View mode is specifically designed for display on a TV and NOT a computer monitor, then shouldn't it follow the rules for the display of images on a TV monitor?  In it's current form, it's not following these rules.

Regarding graphics cards' ability to adjust the image, many cards can't do this, and others only allow 2 settings -- overscan and underscan.  Using underscan puts the image well in from the edges of the screen with a black border around the entire image.  This is 1) bad for the tube due to uneven wear and 2) (once again) NTSC images will literally be incorrectly displayed when using this setting.

Rather than making adjustments to the graphics card settings depending on what you're viewing, it makes more sense to just make the Theater View follow the industry standard rules for displaying images on a TV monitor -- after all, this is what this mode was designed for.

Larry
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Rob L

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #12 on: April 16, 2004, 05:35:30 pm »

But the point is that your graphics card is REALLY crappy if it doesn't allow you to adjust the image - that means it's USELESS for doing anything other than showing stuff where you don't mind losing a fair amount of the picture.

You're going to have the same problem with a whole load of things, not just Media Center.

And it's not *that* difficult to adjust the card - most cards. Powerstrip, and it's not the only utility, does support a HELL of a lot of different cards.

That said, if you really do want to lose a lot of the display output, then it's presumably not that big a deal to tweak the theatreview layout to accommodate it - but it'll be annoying for everyone else to then have that extra space round the outside wasted as a result!

By the way, is NTSC a lot worse in this respect than PAL? It certainly sounds like it...
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lalittle

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #13 on: April 16, 2004, 06:29:09 pm »

But the point is that your graphics card is REALLY crappy if it doesn't allow you to adjust the image - that means it's USELESS for doing anything other than showing stuff where you don't mind losing a fair amount of the picture.

First, most people would not consider nvidia cards "crappy" just because they only allow for two modes -- overscan and underscan.  Second, the card does what it's designed to do just fine -- display output designed for TV on a TV monitor.  When you use the card in this manner, you're not losing ANY picture that you are supposed to be able to see -- the only part of the image you lose is the part that you're "supposed" to lose.

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You're going to have the same problem with a whole load of things, not just Media Center.

I use the card's TV output for things like video editing.  For these type of applicaitons, adjusting the card to eliminate overscan would be an INCORRECT way to set it up.  If I adjusted the card so that the current Theater View fully fit on the TV screen, then the image would be improperly calibrated for viewing NTSC images.

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And it's not *that* difficult to adjust the card - most cards. Powerstrip, and it's not the only utility, does support a HELL of a lot of different cards.

Again, this is not about whether or not it's possible to eliminate overscan -- it's about the fact that you shouldn't HAVE to.  If Theater View mode is designed for display on a TV monitor, why shouldn't it follow the industry standard rules for displaying images on a TV monitor?  Why not design it to follow the same rules that ALL other devices designed for outputting to a TV monitor follow?

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That said, if you really do want to lose a lot of the display output,

I don't want to "lose a lot of display output."  I want to have the Theater View, which was presumably designed to be viewed in a home theater type situation, work like EVERY other component designed for home theater -- i.e. every DVD player, videotape player, satellite receiver, cable box, laserdisc player, etc. out there.  Would you claim that all these other devices "lose a lot of their display?"  They all work exactly how I say Theater View should work.

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then it's presumably not that big a deal to tweak the theatreview layout to accommodate it

I am doing just that -- so far so good.

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but it'll be annoying for everyone else to then have that extra space round the outside wasted as a result!

I think you'll find that the opposite is the case -- i.e. that most people would prefer to have the image display properly with the standard overscan settings.  This means that for most people, it will work by default without having to adjust the graphics card settings (which the average joe might not even know how to do.)  What I'm suggesting is also the only way for the higher end crowd to properly set up a their PCs as HTPCs (Home Theater PCs.)  A properly set up HTPC requires a standard amount of overscan to be used.  If a HTPC is technically set up "correctly," the current MC Theater View will have the information on the edges of the screen cut off.  If, on the other hand, you tweak the graphics card settings to eliminate overscan, then you will no longer have properly calibrated output from your HTPC.

That aside, is having the buttoms and information set it a little from the edges of the screen really that big of a deal for the people that insist on eliminating overscan?  In other words, which is worse; having some people "waste" a little space around the edges of the screen, or having some people lose portions of the buttons and information?  It seems to me that the best solution would be to do it "right" (i.e follow industry standards for displaying images on a TV monitor) and have all the information visible to everybody all the time.

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By the way, is NTSC a lot worse in this respect than PAL? It certainly sounds like it...

I don't know -- perhaps NTSC uses more overscan.

Larry
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lalittle

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #14 on: April 16, 2004, 09:24:20 pm »

Scarpad,

I sent you two Theater View skins edited to account for overscan.  Did you get them?

Larry
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salsbst1

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #15 on: April 20, 2004, 07:21:25 am »

I worked hard to get compensate for and avoid overscan on my TV.  If MC took it upon itself to compensate (and thus overcompensate) for overscan I think I'd blow a gasket.
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lalittle

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Re:Theater View not accounting for properly calibrated TV overscan.
« Reply #16 on: April 20, 2004, 05:23:14 pm »

I worked hard to get compensate for and avoid overscan on my TV.  If MC took it upon itself to compensate (and thus overcompensate) for overscan I think I'd blow a gasket.

I'm simply advocating that images designed for display on a TV should follow the INDUSTRY STANDARD rules for displaying images on a TV.  EVERY TV and EVERY COMPONENT (DVD players, VCRs, Satellite Receivers, etc) is designed with overscan in mind, and ALL program material made for TV is made to account for this.  Why are some people so set on the idea that this ONE device should break the rules that EVERY other device follows?

Here is the important thing to note:  If the Theater View skins account for overscan, the people that adjust their systems to eliminate overscan can STILL use Theater View just fine -- the buttons will simply be a little bit smaller and a little bit in from the edges of the screen.  In a practical sense, this will have no effect on their use of this mode -- I seriously doubt many people would even take notice of it.  These people can continue to eliminate overscan and continue to use Theater View normally.

The situation is not so friendly the other way around.  If the skins DON'T account for overscan, then the people that want to continue using industry standard overscan settings (the Home Theater PC crowd, for example) will be hampered by the fact that when using Theater View, the buttons and information on the edges of the screen get cut off.  Their use of the Theater View skins is far from "uneffected" by this situation.

Doesn't it make a lot more sense to design the system so that it "works" for everybody rather than forcing people to make adjustments that they don't want?  The bottom line, once again, is that the Theater View is designed for TV, so why not follow the rules of ALL other devices and program material designed for TV?

Then again, MC could always offer both types of skins.  In the end, this seems like a waste of time given that the "downside" to the anti-overscan crowd is basically so minor, but it could be done.

Larry
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