Getting my HDTV to work with my PC

Jul 06 2007
A FAQ to help you understand your HDTV options with an eye to HTPC usage.

What is my HDTV's native resolution?

Don't confuse "native resolution" with resolutions an HDTV set can accept. HDTVs can usually accept all formats of digital TV but they are up/down converted to the native resolution(s) of the TV.

CRT based HDTVs - (both direct-view and rear projection) Usually have two native resolutions due to their flexable nature. It is typically 480p and 1080i, in lieu of 480p a slightly different resolution colloquially called 540p (1/4 1080) is common for many RP CRT sets.

DLP, LCD, and LCoS projection - These are all fixed pixel technologies and thus have one native resolution, generally this is 720p or 1080p on the newest sets.

Flat-screen panels like plasma and LCD based TVs - These also have one native resolution. The native resolution varies highly from low-end to high-end class and can get rather complex.

The most basic Plasma displays are EDTV which is 16:9 480p (852x480). They often move up to an odd resolution of 1024x768 with a 16:9 pixel configuration or the even more exotic 1024x512 with 16:9 pixels - also called "ALIS" (Alternating Lighting of Surface) - marketing speak refers to this as 1024x1024.

These TVs, due to their odd rectangular pixel setup, are hard to get working in a pixel perfect arrangement.

Many LCD HDTV sets are exactly 720p (1280x720), this makes them perfect for connection to just about any device.  

The other common resolution you may find in many 32" and larger LCDs, as well as 50" Plasmas TVs, is 1366x768 which is a proper 16:9 resolution that has 768 lines instead of the Digital TV standard of 720 lines. This is the current marketing fad -- to have a flat panel that is "more then 720p" yet it is not 1080p which would be the next proper DTV display standard above 720p. Very few devices can match the exact resolution, meaning most devices are scaled up/down internally to the panel's resolution. PC's are one of the few devices that can output proper timings for 768p (with a minor caveat). See the section below about 1366x768 flat panels and PC interfacing. 

Many new Plasma and LCD TVs are 1920x1080 (1080p) and again this is perfect for connection to just about any device because this is a standardized digital TV resolution that PCs and consumer electronic devices support.

I have a 1024x768 16:9 Plasma what can I do to keep it at the native resolution?

Remember that 1024x768 is a 4:3 resolution to a PC, of course it will be stretched when displayed on the widescreen plasma display, the good news is that specific applications can compensate for it. SageTV 4.x, BeyondTV 4.x, and ZoomPlayer Professional have settings to change the aspect ratio and put content back into the proper ratio.

BeyondTV has a "Non-Square Pixel Compensation" setting.

SageTV under Detailed Setup--> Multimedia are Aspect Ratio settings including an "Aspect Ratio Mode" to force an aspect and then an "Aspect Ratio Settings" to adjust the percentage of stretch.

ZoomPlayer Pro has an Aspect Ratio control panel, in this you can input your resolution and the actual ratio of your display in the "Aspect Ratio Relative Stretch Calculator" and ZoomPlayer will then apply the appropriate stretch percentage.

For a Vista Media Center hack see this AVSForum thread.

So I have one of the 1366x768 flat panels how do I get the best results with it?

Using 1366x768 causes one issue for a PC which is that 1366 pixels is not divisible by 8 and due to legacy issues PC graphics cards cannot typically produce a resolution that isn't divisible by eight. Thus 1360x768 or 1368x768 are the closest resolutions. The newest drivers from NVIDIA and ATI are fairly good at working with the 1366x768 sets and can set 1368 and trim 2 pixels off to match it.

NOTE: Custom resolutions such as 1360x768 are only available with VGA or DVI/HDMI. Component video ouput is locked into the standard DTV resolutions (480i, 480p, 576i, 576p, 720p, 1080i).

There is one problem that may prevent any 1366x768 compatible resolution from working which is not a PC problem. Many TV vendors do not expect a PC to be connected via DVI/HDMI, as such the DVI/HDMI input only accepts standard Digital TV type resolutions. Download MonInfoand run it, it will tell you the various timings the port will accept. If you don't see a 136*x768 timing listed there isn't much you can do: try 720p or 1080i (or even better, 1080p if the TV supports it) and see how it scales, or switch to VGA. Many vendors of 1366x768 sets that include a VGA port allow the custom timings over VGA.

I have an LCD HDTV and it only allows 1024x768 or 1280x1024 (which are standard non-widescreen PC resolutions) so everything is stretched, what gives?

Sadly there are multiple vendors out there that don't think you, the PC user/consumer, knows how to set a proper 16:9 HDTV compatible resolution with your PC and thus limit the VGA input to standard 4:3 PC resolutions... even though it means it will be stretched. Sorry! Try DVI/HDMI.

What is my HDTV's scaler and/or video processor?

Your HDTV has to be able to accept all common SD and HD formats (this includes 480i/576i, 480p/576p, 720p, and 1080i) no matter what the TV's actual native resolution is. So to handle these different inputs your HDTV set has an analog to digital converter for the analog inputs (the analog tuner, composite, s-video, and component). Once the signal is in digital form [if it wasn't already] your TV's scaler processes the image to match the native resolution of your HDTV. This can include upscaling/downscaling and deinterlacing. This step is especially important for fixed-pixel type displays that really only look good when data is fed to it at native resolution.

What is up-conversion, down-conversion, and deinterlacing?

Your HDTV has special electronics to convert all incoming signals to its native resolution. To do this a signal may need to be converted with various algorithms to a higher resolution (up-conversion) or possibly filtered down to a lower resolution (down-conversion). If the signal is interlaced such as good old analog TV (480i/576i) the HDTV must stitch the interlaced lines back together for display when using a progressive scan screen.

For example: If one has a 720p native LCD HDTV when one watches standard analog cable TV it is converted into digital, deinterlaced, and then up-converted to 720p to match the TV's native resolution. Most HDTV broadcasts are 1080i, so when one watches an HDTV channel off the air the TV's video processing unit deinterlaces it and then filters it down to 720p.

What resolution should I use for my HDTV set?

Generally the answer is: the native resolution of your HDTV set.
With CRT tehnology TVs this gets a little harder to answer, 480p is nice if you need to work with things other then an HTPC front end. But 1080i is a proper HDTV resolution.

The other complication is if you have one of the plasma TVs with the oddball setup that uses 1024x768 or 1024x512/ALIS but in a 16:9 pixel configuration. Here you will probably want to pick one of the standard DTV resolutions it supports and see how the internal scaling of the display handles things, 720p would be the closest resolution.

I have a projector what is the best resolution to use for it?

This is a lot like the fixed pixel question, if the projector does a good job with its' scaler you may very well find you like a higher resolution then the native of the projector. Again it depends on the technology your projector uses, the notes on rear-projection sets based on the same technology apply here too.

What refresh rate should I use?

HDTV sets are consumer electronics. They don't have a "refresh rate" that you can set in the same way a PC monitor does. In countries on a 60hz power cycle you need to use a 60hz refresh rate. In other countries where a 50Hz power cycle is used, a 50Hz refresh rate should be set, many new HDTV sets sold in 50Hz countries accept 60Hz input too. Anything higher may cause permanent harm to your TV set.

NOTE: This is changing with select high-end digital displays that operate at 72Hz or 120Hz to make a perfect multiplication from 24fps film material. Currently this is rare so don't set above 60Hz unless you know you have the specific premium plasma model from Pioneer

Why does my 1080i native set flicker so much?

Interlaced resolutions only draw every-other line on the screen at any one time. Because of this the otherwise fine details are diminished and a clear refreshing is visable. When watching video or using a GUI optimised for TV use this tends to be easily ignored, after all standard TV is interlaced and we have been watching that for 50+ years. When looking at a fine detailed GUI, such as the Windows desktop, interlacing become painfully apparent. Interlaced video is hardly ideal and is especially true when connecting a PC to an HDTV. Because of these issues 1080p native HDTV sets seem to be the holy grail of home theater and PC to HDTV connections.

What is this PowerStrip (often abbreviated "PS") I hear about?

PowerStrip is a display utility by Entech Taiwan. It offers a ton of tools. You can see the whole list at the Entech site. The features we are usually concerned with for HTPC use are the custom resolution tools. PowerStrip allows you to make a custom resolution with the timings that best match your TV set.

Do I have to use PowerStrip?

Typically you do not have to use PowerStrip. Both NVIDIA and ATI have excellent support for HDMI/DVI and component output, both vendors include HDTV resolution presets and offer the optional ability to enable overscan compensation.

NOTE: NVIDIA's current display drivers seem to not allow custom resolutions created from PowerStrip.

The top/bottom/sides of my screen are going past the edge! What do I do?

That is normal, a television set overscans on purpose. This is to hide minor imperfections that are often at the edges of analog TV signals. This is also to have TV completely fill your screen. PC output (along with proper HD sources such as HD DVD and Blu-ray players) generally doesn't suffer this issue so minimizing the overscan is often desired. ATI and NVIDIA's drivers offer methods of overscan compensation. PowerStrip can also help you by making a custom resolution inside a standard timing. Ideally you do not want to do this with your PC, the HDTV should have a 1:1 mode (also called 'dot-by-dot', 'pixel-by-pixel', or 'Just Scan') which removes the overscan, overscan is not necessary for a digital display, especially when it is being fed a digital source.

I setup my display just fine, but when I reboot Windows sets the resolution back to 800x600 or 640x480, what do I do?

Some HDTVs, projectors, etc. seem to confuse Windows for various reasons.

The first step is to make sure you have up-to-date drivers for your video card.

If you are using an NVIDIA card you might need to try toggling "Force TV Detection" and if you set an overscan preference check the box for "Remember my preferences". Also if you are connected via DVI/HDMI you may need to check the "Treat Digital Display as HDTV" option.

If these tips don't work you can try forcing a monitor profile instead of the generic "Plug and Play Monitor" driver. The most common driver to use comes with Windows XP and supports HDTV resolutions is the Sony W900, this is what I colloqually call "The Sony Trick". For more see the next section below.


The "Sony Trick"
-------------------

Open up the Display Properties, choose the Settings tab, and click Advanced. Click on the Monitor tab. Make sure you have the correct monitor selected if you have more then one device connected (for example: a PC monitor and an HDTV) and click Properties. Click the Driver tab. Click Update Driver. Choose "Install from a list or a specific location (advanced)". Now click the little radio button next to the "Don't Search. I will chose the driver to install." You will then have to uncheck the "Show compatible hardware" box. Now scroll down for the Sony section. Choose Sony GDM-W900. This should (but it doesn't always) override the what the PnP info from the HDTV was telling your PC. Click OK to let it update, and now notice you have tons of resolutions, including some preset HDTV ones.

NOTE: The Sony Trick is only useful for output types that are seen as a monitor (this means VGA or DVI/HDMI only). Component output from a video card is done somewhat differently and is not normally customizable.

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