Thread: How can I improve TV picture quality?

I just built my first Mythtv system and everything works, including lirc to change channels on my Dish Network STB. The problem is, video output to the TV looks like crap. Text is blurry and there is a lot of color shadowing effects on screen. Of course, output to a monitor looks great. Here are details of video for the system:

Input: PVR150 card using composite output from Dish Network Satellite box

Output: S-video output on an FX 5200 Nvidia card. The S-video output is converted to composite and fed to the TV.

TV: It is an old 27 inch CRT. It handles 800x600 resolution or 640x480. I'm in the USA, so it is NTSC-M.

Video Driver: I'm running Ubuntu 7.04 and I am using the "nvidia-glx" module available from Ubuntu repositories.

I thought it might be the conversion from S-video out to composite causing the problem. However, I tried a second computer (with similar hardware) that has a video card with composite out. The second computer had similarly bad video quality on TV output. I also tried connecting it up with different composite cables. If I try composite input directly from my satellite STB or output from my DVD player, it looks great.

I've done a fair amount of reading about this and it seems like S-video and composite out is generally bad. Unfortunately, my TV is old and doesn't have S-video, component, DVI, or VGA inputs. I only have coaxial cable and composite inputs. I've tried changing the output resolution from 800x600 to 640x480 and they are both equally bad.

So is there anything I can do to improve picture quality? Would a VGA scan converter like these:



www<dot>ramelectronics<dot>net/html/PC-TV_GEZ-1000.html
www<dot>ramelectronics<dot>net/html/PC-TV_GTM-2000.html

or perhaps:

www<dot>compusa<dot>com/products/product_info.asp?pfp=BROWSE&N=200366&product_code= 50186965

result in better picture quality?

I'm a little frustrated after spending so much time getting this set up. I managed to put together a relatively inexpensive, quiet system (mostly from junk parts off of ebay) and the performance is great. I know the best solution would be to buy a new LCD TV with VGA inputs, but that just isn't in the budget right now.

Well, I just ordered a "grandtec ultimate 2000" scan converter from Amazon.com. It was $64. I'm not sure if it will offer better video quality than TV-out from my video card, but it is a whole lot less expensive than buying a TV.

I've searched around and I can't find anyone who has reported a head-to-head comparison between a scan converter and TV-out from a video card. I'll report how it works when I get it in 5-9 business days.

I found a scan converter on sale at my local radio shack for $60, so I bought one. For anyone who cares, the scan converter produces a little better picture quality, but don't expect to use your low definition television for web browsing. It is OK for movies. In fact, the quality for video is similar to what I get from my DVD player. Text is still hard to read, even for low resolution settings.

Thanks for posting the results of your test. I was wondering about those converters but never jumped on the bandwagon.

The specific model I got is made by Grandtec and is called "PC to Video Component" (model# GXP-2000). Radio Shack told me they are on clearance and they won't carry that model anymore and instead will carry a model by a different manufacturer. There are a lot of places on the web that sell the same or similar models.

The nice thing about the scan converter is it has a remote control that enables one to adjust picture quality (brightness, contrast, hue) and also the horizontal and vertical position. Since it is working off the VGA port, there are no driver/module issues in Linux to contend with.

After some further experimentation, I found that my television always has some ghosting images, especially with red color. It appears that the scan converter produces the same quality as coming from the satellite set top box. I watched a DVD using Mplayer and the scan converter to output to my TV. The quality was indistinguishable from the output from my DVD player. (all connections made with composite cables).

If I had it all to do over again, I would buy the scan converter and get the least expensive video card I could find. The scan converter is much easier and more flexible. You don't have to install a driver and manually edit the xorg.conf file like you do for TV-out on a video card.

Thanks for the info, I want to try this soon.