View Full Version : [ubuntu] 1366x768 on TV

July 12th, 2009, 10:51 AM
I have a media centre PC set up and, up until now, have been using windows XP. The screen is a 32" LCD TV with a native resolution of 1366x768 (at least that is what i have assumed until recently).

I recently found the TVtime application for Ubuntu and have since installed Ubuntu on the PC. In windows, the resolution is set to 1366x768 and it fills the screen nicely. When i first installed Ubuntu, the screen acctually said unknown signal.

After sifting through large amounts of forum posts (and about 4 hours later) i am finally able to get the screen to accept a resolution of 1360x768 but the screen picks it up as 1280x768 and thus leaves me with a squashed image and black bars on either side. I achieved this by manually editing the xorg.conf file. When i try manually setting a resolution of 1366x768 (as opposed to 1360x768 ) the screen clearly doesn't like it and displays a very broken image. The screen manual actually says that the maximum resolution is 1360x768 @ 60Hz

1) If the native resolution is in fact 1360x768 as the manual claims, then why does the screen pick it up as 1280x768?

2) Where does 1366 come from? Both windows and the store i bought it from are convinced that this is the correct horizontal resolution.

It seems to me like the world of TV screens is riddled with broken standards and Microsoft, being quite accustomed to broken standards, is happy to pull a quick fix and disguise it as a different resolution. Linux therefore gets the short end of the stick because no honourable Linux developer would allow a workaround in his code.

Is there a solution to this or do i have to accept a resolution of 1360x768 crammed into a 1280x768 block?

July 12th, 2009, 06:09 PM
Yes I found this gotcha when I hooked up a Linux machine with an nvidia card to my 32" LCD TV. The TV resolution is 1366x768, but the card/driver put out 1360x768. (This also happened when I tried a Mac Mini.) Unlike your setup, my TV did its best with 1360 (it didn't think it was 1280x768 ) but the display was very disappointing. Stretching the image over those 6 extra pixels made for some unpleasant artefacts.

I was about to give up when I found hidden deep within the TV configuration menu an equivalent to 'auto' or 'auto adjustment' on a computer monitor. The TV tuned itself into the computer video output and the result was splendid. There were two thin vertical black strips (presumably 3 pixels wide) either side of the image, but the rest was fine.

Have a look in your TV menu. You might be lucky.

Interesting that you found that Windows puts out 1366x768. I'm sure I had the same problem in Windows as in Linux, but this was a couple of years ago so I might be misremembering. What is a fact is that MacOS gave me the same problem, solvable the same way with the auto function in the TV.

July 12th, 2009, 07:56 PM
Check you cable connection between the TV and computer. I have two vga extension cables, if I use on I get resolution problems and the tv is not detected properly. If I daisy chain the two cables, my tv is detected properly and the native resolution of 1366X768 is used.

July 13th, 2009, 11:32 AM
I really should have thought of that, thanks coffeecat. I actually set the screen to "Do not distort image" ages ago so that it wouldn't stretch smaller resolutions like 1024x768 but i suppose in this case it would be appropriate. It'll be 6 pixels too long though and possibly still omit some pixels because of picking it up as 1280x768. I'll give it a try later.

By the way, i have a nvidia card as well and the TV is connected via VGA cable since it doesn't have a DVI port. It does however have HDMI, do you get DVI to HDMI cables? I haven't done my homework on that. The daisy chain idea just sounds a bit dodgey but i'll give it a try if the stretching doesn't work out. Thanks guys.

July 17th, 2009, 07:46 PM
Image looks good, although still being detected as 1280x768, there's no distortion and it fills the screen nicely.

July 17th, 2010, 04:26 PM
It's exactly a year ago i was having this issue, interesting. I have set up the same media centre PC again with the same screen, i've installed Ubuntu 10.04 and as it was doing a year ago, the screen is picking up 1360x768 as 1280x768.

I would be happy with the "fill screen" solution i used last time but this time it's cutting off about 40 pixels on the right. The power button and username in the top right corner of Ubuntu are completely cut off.

I think the problem is actually with the nvidia drivers so i'd like to give the nouveau drivers a try. Default Ubuntu configuration wouldn't let me select anything above 1024x768 so if nouveau is installed by default then i'm out of ideas. Can anyone give me some insight?

July 17th, 2010, 05:50 PM
After pressing auto adjust on the TV numerous times the 1360x768 image now fits in the 1280x768 box which i have then stretched to fill the screen. This will do for the time being.

July 17th, 2010, 07:36 PM
By the way, i have a nvidia card as well and the TV is connected via VGA cable since it doesn't have a DVI port. It does however have HDMI, do you get DVI to HDMI cables?Yep, you certainly can get DVI->HDMI cables (and vice-versa too). I have nVidia DVI -> HDMI -> TV on my media centre. :)

August 29th, 2010, 02:18 PM
Most video cards/drivers need the horizontal pixel count to be a multiple of 8 - you can choose 1360 and have three blank pixels at each side of the screen, or 1368 and have a pixel disappear off each end. You'll probably need to generate a custom modeline to get these resolutions, there are various tools to do this including this one: http://xtiming.sourceforge.net/cgi-bin/xtiming.pl