Hooking up your PC to your HDTV set
date written: march 22, 2005 11pm

Most HDTV sets have Composite, Component-In(YPbPr), DVI and S-video inputs. Newer HDTVs support HDMI inputs. My HDTV does not support HDMI input. It's not a crisis though. My Mitsubishi WS 48313 supports 480i, 480p and 1080i resolutions and these are native.

After almost a year of usage, that was early December 2004, I realized that I was not using the full potentials of my hdtv. So, I went to Wal-Mart and bought the US Digital HDTV receiver. This is an Off-The-Air(OTA) HDTV receiver. I connected my external roof-mounted RadioShack VHF/UHF antenna to the receiver via Component(YPbPr) cable and initiated channel scanning. I was disappointed because during the scan, the receiver froze while scanning channel 36. I waited for 2 hours and nothing happened. Fortunately but was not really aware, I rotated my antenna using the Radio Shack rotor and I restarted the scan again. This time, the scan finished its process. I went to Antennaweb to find out what digital channels were available in my area. I tuned to channel 11 WTTW-DT and was amazed when I saw the picture quality. Weeks passed, I noticed that something was missing with the current setup. Paying $198 for an hd equipment that only does video output and not record was totally ridiculous and impractical. Well, you've guessed what I did just like what you guys do. I returned it! Hehehe! After that, I did more and more and more research....and gladly found my new wife, Mythtv. :)

For more information on how I was able to build the same functionality but using opensource technology, please visit my Building your High Definition HTPC.

I bought the Nvidia 6600 GT card for its PureVideo technology support. The card I got which is a Leadtek Winfast A6600 GT comes with 3 video output interfaces, 15pin VGA female, DVI-I female and a proprietary 6 pin PS2 S-video interface. The package came with a 6 pin PS2 S-video to Component YPbPr converter and DVI-male to VGA 15pin female converter. I would like to highly emphasize that this card is not a capture/tuner card. I bought a different PCI card for capturing HD OTA contents and that is the Air2PC card.

I started searching on how I can use my hdtv as my computer monitor. I was really afraid of using my hdtv as my computer monitor because in the Mitsubishi manual, it mentioned that the DVI input is not compatible with personal computer's vga output. So, there was a chance of breaking or frying the chips once I start bombarding the DVI port on the HDTV set using an incorrect Horizontal and Vertical refresh rates. Eventhough I was in the doubting or state of fear, I went to Wal-Mart and bought a 6 ft DVI cable. However, the fear still prevented me from hooking it up. I contacted Nvidia and mentioned to them that my Mitsubishi supports EIA-861B standard. Well, what the Nvidia support guy told me is that I should be fine. All I have to do is to download the latest Windows XP driver on their site and hook it up to the DVI out of the card and onto the DVI input of the HDTV. Well, with this, I had to shutdown my Fedora(FC3) and had to find an idle harddisk where I can install Windows XP. To put it in a nutshell, I was able to drive my HDTV at 1920x1080i using Windows XP. This testing proved that it should work in Linux. Well, the tough part was to generate a custom 1920x1080 modeline that will be used by Xorg or XFree86. Configuring resolution in X is totatlly way different in Windows XP. I've got to send kudos to Bill Gates about that click-click change mode functionality. Fortunately, some guys at http://www.highdefforum.com did have an article about modelines and how to get them. I read the thread and followed. I downloaded the moninfo and powerstrip tools for Windows XP. Using moninfo.exe, I was able to retrieve the EDID information from my Mitsubishi set. More information about EDID can be read here. Remember, you can only download EDID information via DVI connection.

BTW, I wrote a HOWTO about compiling and installing the latest kernel(2.6.11.6 as of this writing) with air2pc support. The link also contains a HOWTO about installing latest Nvidia graphics driver(1.0-7167 as of this writing). You can find it here.

Before I started messing up with my HDTV, I tested the card using a regular vga monitor. As my experimentation continued in X-windows(Xorg) in Linux, I went through tons of hurdles on how I can get 1920x1080 resolution to work properly with Linux and hdtv set via the MonLink input channel(the DVI). I was only able to set my resolution to 640x480 and 320x200. This was totally unacceptable. Fonts were HUGE! I contacted Mitsubishi and asked about EDID information. They said that my WS 48313 can only do 640x480. I really couldn't believe that even Mitsubishi didn't know their product well. LOL! Luckily, README.txt from Nvidia linux driver came to the rescue. There was a way to prevent the HDTV set from sending its EDID information to the video card. This way, I can force X to use my own horizontal/vertical refresh rates and resolutions. The line was

Option "NoDDC" "TRUE"

This is similar to IgnoreEDID option. Please refer to the Nvidia README.txt for more information about options.

After spending 3 days of continuous troubleshooting, I got it to work. However, new issues came up which was people call it interlace bug. I have another article here that tackles deeply about the issues/bugs that I've found when using different Xorg configuration. I have escalated this to Nvidia in IRC and they even spent hours with me troubleshooting why tearing was evident on the DVI interface. Actually, it was not only tearing that was happening but CPU also goes to 99%. Please refer to my article for more information about it. The tearing however was not really annoying but sometimes, it just affects the awesome quality of an HD program. I went back to IRC freenode and chatted with my friends at mythtv users. They kept telling me that there is a bug in all the Linux Nvidia drivers that uses the DVI output port. Folks there told me that my only hope was to buy the VGA to Component Video Converter 9A69 from Audio Authority and this was the route that some mythtv folks did and they got rid of the tearing issues. I told myself that this hobby was becoming expensive. I also told myself that I will just have to wait for Nvidia to come up with a bug free Linux driver but that may take years.

One month passed. I went back to continue troubleshooting as to why tearing happens. It was becoming really annoying. I tried so many combinations in /etc/X11/xorg.conf but I never had any success. I was actually at the point where I want to replace Xv or XvMC overlay support in mythtv. It's because, I've noticed that mplayer experiences the same problems too when using these 2 overlay libraries. But if I use different library such as gl, x11 or sdl, I am able to watch an mpeg2 file in mplayer. However, eventhough it was working in single headed configuration, the tearing didn't go away. Huh?!?! It was a PITA!!! I just told myself that early morning, that I have to accept the reality that (a) hdtv is not capable, (b) Xv library is hosed or (c) the Nvidia graphics driver is b0rk3d!!!

I went back to my Mitsubishi manual and got interested in the DTV input channel. In the manual, it mentioned that it supports RGBHV signal. This text reminded me of my first job as technical support guy when I was supporting our CAD engineers. They had huge EIZO monitors which they use for their Autocad v13 applications. I used to replace their monitors when it gets faulty. These monitors have RGB inputs using BNC connectors plus two other connectors, HV w/c I didn't know at time. I just matched it. :) I went back to my manual and also looked at the back of my WS 48313. I found out that my hdtv has RGBHV input, however it was an RCA type connector. Click here to see a screenshot of the RGBHV input RCA ports. I was so exicited that I bought the 6ft VGA HD15 to Component cable. I read some topics about it and I assumed that this cable will have a sync on Green. Unfortunately, it didn't work. This was putting pressure because I was thinking that maybe, the only working solution to utilize the VGA primary port on the Nvidia card was to buy the VGA to Component Video Converter 9A69. I searched again for another whole day and found this link. I kept a local copy of the pinouts that was geared towards my requirement and that is building VGA to RGBHV connector. I went to Radio shack and bought a cheap 75 ohm 6 pieces of RCA connectors( $3.99), one VGA 15pin male connector($1.75) and one VGA housing(~$2.99). So, here is the cable that I came up with that used this pinout settings. The cable I built looks really poor since I used 2 separate UTP network cables. I needed 5 pairs. I connected the VGA-to-RGBHV cable to the DTV input on the HDTV. You can see it here. I turned on my HDTV and change to DTV input. Guess what? Nothing happened. I rebooted Linux just like I did when I use the cable I bought from cablewholesale.com. Using the cable from cablewholesale, even when I rebooted Linux, I still didn't see any video output on my HDTV. But using the homebrew VGA-to-RGBHV cable, I was able to see the BIOS during bootup. GDM gui was displayed in my HDTV at 1080i(which I was already getting back when I was using DVI cable). I quickly login to find out if system will come to a freeze when I start watching any recorded programs in mythtv. I selected American Idol recorded last March 15. I was expecting a CPU pegged but guess what, it didn't freeze, mythtv happily played the recorded program. And the greatest thing about it is that the tearing went away. We know that Channel 32 or FOX channel broadcasts their programs in 720p. This was one of the things I was thinking that could be causing the tearing. But I was wrong. Even if my Xorg is set to 1080i, I don't see anymore tearing even on the fastest scenes. I'm really ecstatic on the results and especially, it only costs me $9 to build this cable. Here are some pics I took this afternoon.

nadia.jpg
vonzell.jpg
simon.jpg
wttw1.jpg
wttw2.jpg
weeklyexplorer.jpg
csi miami high defintion
1080p quicktime movie screenshotsNEW!!!

The screenshots above doesn't really give justice. Picture is so real when you are in front of it. That's one of the strength of a CRT rear projection TV. Even if it's an old technology, it doesn't suffer from Screen Door Effect like LCD/DLP does. This is another reason why I'm going to buy a 3-tube CRT projector in the future.

And for the working /etc/X11/xorg.conf, I'm currently using this configuration. You will see tons of modelines in the configuration file. I mentioned this earlier. Rather than rebooting back n' forth to XP to generate a new modeline, I'm just using this link to generate my own custom modeline.