My LCD just won't map 1 to 1!

[kieswled]

Hello everybody!

I have a 26' Toshiba, HD Ready (1366X768). I'm connecting it via VGA with my laptop.

The problem is that I simply cannot make the bloody LCD map 1 to 1 despite the right resolution!

I managed to force the video card to output 1366x768 using Powerstrip. (1360 and 1368 are also possible) Vertically, there is perfect pixel mapping (768), but horizontally not.
When displaying 1024X768, there is perfect pixel mapping on both dimensions (after setting 4:3 in the TV and getting huge black bands on the sides), so it is possible!
I thought the problem might me over/underscan, but playing around H-size, H-position and Phase didn't make it better. (I used the dedicated picture in "Nokia monitor tester" to tell if it's getting better or worse)
The TV doesn't have a lot of options I can set. It just has the ones mentioned above, and on "auto" it just stretches the image to fit the screen.
How can I not get 1:1 when the TV gets exactly the same number of pixels it can display? Could there be a problem with the geometry?

Any ideas? Remember, the problem is only with the H axis, the V one is perfect.

[scaryjim]

The TV could be lying about its capabilities?

I've only ever dealt with 1 1366x768 monitor - a cheapish 19" widescreen - and it had horrendous striping on the horizontal plane - very much like a TFT running at something other that its native resolution. Of course, there's no way a manufacturer would admit to it, but I strongly suspect that the panels are *not* natively 1366x768, and that resolution is only supported through horizontal scaling. Try some resolutions with a smaller horizontal size - maybe 1280x768?

[jimbouk]

I had exactly the same problem on a shiny Sony 32" TV my housemates bought. TVs just aren't designed to work as monitors. It could be a refresh rate issue confusing things, the graphics card will output at 60Hz I assume, would the TV be on 50Hz or 48Hz or similar?

[scaryjim]

... TVs just aren't designed to work as monitors. ...

It depends on the TV. I have a 26" 1280x768 TV that works perfectly with my PC on both VGA and DVI connections. But I strongly suspect that a lot of manufacturers claim a 16:9 ratio when they use 16:10 panels... which would give the problems with horizontal sync the OP is experiencing while leaving the vertical sync fine...

I thought if the GPU was issuing a higher refresh rate than the monitor / TV could cope with it'd just complain outright with a "signal out of range" message?

[KidChameleon]

I had a similar problem with my Sony TV recently. I have my HTPC connected by DVI->HDMI and if I set it to 1920x1080 the tv will cut the edges off all around. Apparently it's a problem with the TV not supporting 1:1 over HDMI.

In Ati Catalyst Control Center, setting it to 1080p gave the above problem so I was scaling the image down to fit the screen. That made everything fuzzy and jagged. Then I found out I can set a custom resolution, which ended up being 1824x1024 to fit on the screen. I'm not sure what effect that would have on an HD movie.

It doesn't have that problem through VGA and 1920x1080 looks fine.

[Pob255]

There's another factor that I've hit before when connecting laptops up to projectors, the laptop it self.

what res does your laptop run at? I ask because I've had a lot of issues which are caused by differing resolutions outputs.
Basically most laptops can only output to one resolution, so if your laptop screen is a non-wide screen then it can be next to impossible to get it to output a wide screen signal at the same time. (this sounds like it could be the situation)
The way around it is to set the laptop to display to the exturnal monitor only (commonly it's fn+F5 to cycle between display output settings, but check your laptop because it varies)
Then you may be able to set the resolution correctly.

[kieswled]

Of course, there's no way a manufacturer would admit to it, but I strongly suspect that the panels are *not* natively 1366x768, and that resolution is only supported through horizontal scaling. Try some resolutions with a smaller horizontal size - maybe 1280x768?

I am pretty sure that the panel actually has 1366x768 pixels. I already tried 1280X768 and all other resolutions I could think of.

I had exactly the same problem on a shiny Sony 32" TV my housemates bought. TVs just aren't designed to work as monitors. It could be a refresh rate issue confusing things, the graphics card will output at 60Hz I assume, would the TV be on 50Hz or 48Hz or similar?

The TV's specifications say 60Hz. Anyway, I also tried setting 56 and 50Hz with absolutely no change.

I thought if the GPU was issuing a higher refresh rate than the monitor / TV could cope with it'd just complain outright with a "signal out of range" message?

That's right. As soon as I set the output to more than 60Hz, I get such a message.

There's another factor that I've hit before when connecting laptops up to projectors, the laptop it self.

what res does your laptop run at? I ask because I've had a lot of issues which are caused by differing resolutions outputs.
Basically most laptops can only output to one resolution, so if your laptop screen is a non-wide screen then it can be next to impossible to get it to output a wide screen signal at the same time. (this sounds like it could be the situation)
The way around it is to set the laptop to display to the exturnal monitor only (commonly it's fn+F5 to cycle between display output settings, but check your laptop because it varies)
Then you may be able to set the resolution correctly.

Did you even read my post? I can output whatever resolution I want to from my laptop, that is not the problem. Geez!
And of course I don't just duplicate the desktop. Oh, and: I newer saw a graphic card in my life that could only output one single resolution, just like I newer saw a monitor in my life that could display only one.


Anyway, in case somebody reads this that actually knows what they are talking about: I noticed that I always get at least 6 shady vertical areas (where interpolation is done), regardless of resolution (in the 1280-1368 area) and TV settings. This leads me to think that the bloody TV always makes some kind of rescaling that I cannot control. (maybe to 1360 and then 1366)

[Blaineoliver]

Try 1440x900, my brothers tv bizarely uses this resolution.

[Champman99]

I can only really echo what has been said above. Different TV's have wildling varying capabilities as monitors. My mums Philips a very early (2003), very expensive at the time 30" LCD has a (rather perculiar) native resolution 1280 x 768 of, and will happily run 1080i or 720p but only over component cable. Over VGA it will only accept 1024x768 or 640x480. It was released before the HD ready standard, so doesnt have any HDMI inputs sadly.

Wheras my much more modern LG 26" TV natively supports 1080p ( I use it as monitor) but also maps one to one with every obscure resolution you can think of.

Not much help I know, but TV support with PCs ranges from awesome to terrible.