Overscan question

[MasterRoshi]

I was wondering if LCD tv's also have overscan. I know most if not all CRT tv's have overscan so I tried a sony bravia 46" LCD tv, but the edges are still cut off after burning. I was wondering maybe if it the converting program I used crop off the edges? If I run the .IFO file on my computer and the edges are still there does it mean its not related to the converter and its the TV that did it?

[jagabo]

Most LCDs overscan. Many of the newer 1080p HDTVs have a non-overscan option. For example, my Samsung 4665 has a "Just Scan" mode with no overscan and a "16:9" mode with overscan.

Open your video with VirtualDubMod to see if any has been cut off. From your description it sounds like your encoder did not crop the frame.

[edDV]

Yes they do. They know if they didn't overscan, noobs would be returning their TV's beacuse of all the garbage around the edges.

[JohnnyMalaria]

Yes they do. They know if they didn't overscan, noobs would be returning their TV's beacuse of all the garbage around the edges.

True. But...a lot of prosumer camcorders (DV and HDV) still insist on having overscanned LCD/CRT monitors without the ability to turn it off. The number of times I see vignetting from a teleconverter when viewing on the PC pisses me off to no end. Same for the mic's windsock. It isn't visible when recording nor on an overscanned TV. But for web distribution etc, it requires cropping and rescaling.

So I'm pleased that current LCD TVs overscan...

[MasterRoshi]

Most LCDs overscan. Many of the newer 1080p HDTVs have a non-overscan option. For example, my Samsung 4665 has a "Just Scan" mode with no overscan and a "16:9" mode with overscan.

Open your video with VirtualDubMod to see if any has been cut off. From your description it sounds like your encoder did not crop the frame.

Ok, it doesn't cut off in virtualdubmod, so I guess it is the overscan problem and not a conversion problem. If I burn as a data disc and play on a divx player, will it also be cut off?

[jagabo]

If I burn as a data disc and play on a divx player, will it also be cut off?

Yes, it will still be cut off. The DVD player will send the same image to the TV and the TV will do exactly the same thing.

If your HDTV has a VGA input you might be able to play the video on your computer and see the whole image. HDTVs usually don't overscan the VGA input.

[MasterRoshi]

Hmm ok. One last question about overscan, do all tvs overscan by the same amount or does it depend? I was thinking of adding padding around each edge, is that a common thing for people to do? Or do people just leave the sides cut off...

[JohnnyMalaria]

Hmm ok. One last question about overscan, do all tvs overscan by the same amount or does it depend? I was thinking of adding padding around each edge, is that a common thing for people to do? Or do people just leave the sides cut off...

It depends which is why overscan exists in the first place. Its purpose is to hide the multitude of sins that arise with cheap electronics used for consumer TVs (CRT ones). So values anywhere from 5% to 15% aren't uncommon especially with cheaper and older TVs.

[jagabo]

Hmm ok. One last question about overscan, do all tvs overscan by the same amount

No. It ranges from about 2 percent to 10 percent on each edge. On CRTs the amount of overscan usually isn't even on all four sides. LCDs tend to overscan less than CRTs.

I was thinking of adding padding around each edge, is that a common thing for people to do? Or do people just leave the sides cut off...

People often do that when their video has subtitles near the bottom or sides of the frame.

[manono]

One last question about overscan, do all tvs overscan by the same amount or does it depend?

It depends on the TV set. Some have a small amount cut off, and some have a lot. As near as I can tell you may lose anywhere from almost nothing up to about 20% with 10% perhaps being an average. My Sony LCD loses almost nothing to the overscan. My previous Samsung DLP lost a bit more but had a VGA setting where you saw the whole picture with a thin added black border around the picture.

Personally, I don't add borders around the video to account for the overscan. Some do, especially if they're converting from AVI with burned in subs that sometimes get partially lost in the overscan.

One thing not brought up yet is the fact that quite a few DVD players actually send a cropped picture to the TV set. Then you get hit with a double whammy.

Edit: jagabo was faster.

[lordsmurf]

Not even close. It's a 7% average. It can be as small as 3-4% or as large as 10%. It won't be 20%.

[JohnnyMalaria]

By definition of their very technology (i.e., pixels with perfectly fixed geometry), LCD display panels cannot overscan. Any that seems to occur is because the display's driver is programmed to deliberately rescale the image to lose the traditional overscan region.

[JohnnyMalaria]

Debating the percentages is a bit pointless - it depends on how you are calculating it.

If you are simply saying 5% on each side then that equates to 10% of the total area of the display. 10% per side gives 20% total. Losing a fifth of the image is significant.

The point is that it varies and non-overscanned displays are a pain for the vast majority of video sources and will continue to be so until consumer and prosumer video gathering equipment come with non-overscanned monitors.

[jagabo]

By definition of their very technology (i.e., pixels with perfectly fixed geometry), LCD display panels cannot overscan. Any that seems to occur is because the display's driver is programmed to deliberately rescale the image to lose the traditional overscan region.

This is a pointless distinction in terms of the OP's question.

The point is that it varies and non-overscanned displays are a pain for the vast majority of video sources

I don't find it a pain. But I guess I don't shoot serious video.

[MasterRoshi]

There was actually an option to select "full pixels" on the TV which I believe would show the edges of the video, but I wasn't able to select that option =/

[edDV]

There was actually an option to select "full pixels" on the TV which I believe would show the edges of the video, but I wasn't able to select that option =/

From a TV manufacturer's point of view, 3-5% overscan is a good thing. They got many complaints from computer greeks who fed in their Windows desktop and couldn't see the top and bottom toolbars or the side icons.* The computer gamers chimed in complaining about lost edges. Console games are designed to overscan and have more centralized menus.

The TV industry response was to offer the VGA "PC PORT" without overscan intended for Windows desktops, computer games and Powerpoint / Excel presentations. Only a few manufacturers offer full scan or "just scan" on the analog or HDMI ports.


*ATI, NVidia and Intel added a zoom option to the display card menus to help resize the desktop to compensate for overscan. The downside is blurring caused by resize filters.

[lordsmurf]

By definition of their very technology (i.e., pixels with perfectly fixed geometry), LCD display panels cannot overscan. Any that seems to occur is because the display's driver is programmed to deliberately rescale the image to lose the traditional overscan region.

My Sharp LCD has an overscan. Most all televisions, LCD or not, have an overscan. It has to be done, for legacy support of VHS, traditional signals ... even HD has CC crap on screen.