Wrong screen resolution with HDMI output to HDTV

Question

I own an HDTV with a native resolution of 1360x768.

Sometimes I plug in my laptop to watch movies, and I used to do it with a VGA cable. I've had no problem setting the laptop to the TV native resolution with the VGA cable (1360x768).

Having acquired an HDMI cable recently, I can't go past 1280x720, and if I do, the TV displays "invalid format". At 1280x720, the image is viewable but not centered, so for example I can't see the windows taskbar or titlebars.

I've tried both cables (VGA and HDMI) with the same settings: Laptop's display turned off and trying to set the Tv's native resolution.

What could I try to fix this issue? Could it be a faulty cable? (I'm using a Thinkpad with Windows 7)

EDIT: My graphics adapter appears listed as Mobile Intel(R) 4 Series Express Chipset Family (Searching for my laptop's model yields Intel GMA 4500MHD as the graphic card)

I'm downloading a driver update from Intel's website. I'll report my progress when I check its behavior tomorrow.

Answer 1

Without knowing what your graphics adapter is, there's not much I can suggest. If the following information doesn't help, update your post with information about your graphics adapter (aka video card), and I will update this answer with some more ideas.

Try updating the drivers for your graphics adapter. Here are the most common manufacturers and their driver pages:

• ATI cards (Such as Mobility Radeon): http://support.amd.com/us/Pages/AMDSupportHub.aspx
• nVidia cards (Such as GeForce): http://www.nvidia.com/Download/index.aspx?lang=en-us
• Intel cards: http://downloadcenter.intel.com/default.aspx?iid=gg_support-EN_01+home_downloadctr

Answer 2

VGA is analog, HDMI is digital. When you were connecting your computer to your TV via a VGA cable different hardware in your TV was processing the signal. It is likely that your TV simply cannot process a digital signal of the resolution you are looking for. Most manuals list the resolutions TV's are capable of via different connections, so make sure your TV can support the resolution you want over HDMI.

If the picture looks ok at 1280x720 but it is just off centered then you can press a button on your TV remote to center the picture. Double check your TV manual to see what button does this, but usually it is called something like "View Mode", "Wide", "Stretch", "Zoom", etc.

Another issue might be your GPU itself. It's specs say it is capable of resolutions up to 1080p, but there have been issues of it not working with some resolutions (though your desired resolution is not on the list). I also saw several places where people were having trouble with that chipset in Linux (though I assume you are running Windows).

Answer 3

If your setting is "duplicate displays", the maximum resolution is limited by the display of your laptop. If your setting is using 2 displays, you can set the resolution of the TV-display to be higher.

Furthermore, if your screen is centered on your TV and it's not using full width and height, it might be that your graphic software (like nVidia, AMD, ...) is using an overscan of a certain percentage (mostly 10%). You can set that to 0% to use the full width and height of the TV at all times!