tv quality issues, video/audio

[liquidskin]

Hey All,

I got GB-PVR goin on my old laptop and it looks and sounds great on the laptop monitor. TV guide is working, recording is working, Im really happy with the program.

I guess the problems Im running into, (which I guess have nothing to do with GB-PVR) is that I'm getting these quick diagonal lines moving throughout the whole screen as well as audio interference when the screen colors change.


First, the video..

I'm sending from my laptop an S-VIDEO to a RF modulator to coax. Resolution on the source is at 800x600 with a 60hz. I love the way the video looks on the screen, but I really cant stand it on the TV. The TV is a bit aged (as you could guess from the use of the rf modulator).. Also, I got a pretty low-grade s-video cable. I think I opted for the cheapest one off amazon.

Where should I start in terms of diagnosing that problem? Is it likely that it could be the cable?

In regard to the audio, this is confusing the hell out of me. The TV will sometimes buzz, but it has nothing to do with what's being inputted into the modulator. I can disconnect the audio cables completely and Ill hear the same buzz. It seems to happen when the screen colors change, so I cant figure out how video is affecting audio. For example, I'll be watching a show and hear some buzz, the show will fade to black for commercial and for that second I'll hear silence.

I know its alot, but if anyone can give me any ideas, Id really appreciate it.

Thanks

[liquidskin]

observation: the audio buzz seems to be coming from white picture. the set is silent on a black screen, but if i click over to a white screen on the desktop, it buzzes like crazy.

[Anthony]

I got GB-PVR goin on my old laptop and it looks and sounds great on the laptop monitor. TV guide is working, recording is working, Im really happy with the program. I'm getting these quick diagonal lines moving throughout the whole screen as well as audio interference when the screen colors change. I'm sending from my laptop an S-VIDEO to a RF modulator to coax. Resolution on the source is at 800x600 with a 60hz. I love the way the video looks on the screen, but I really cant stand it on the TV. The TV is a bit aged (as you could guess from the use of the rf modulator).. Also, I got a pretty low-grade s-video cable. I think I opted for the cheapest one off amazon.

First, check all your connections to make sure everything is hooked up correctly.

If your RF modulator lets you switch to a different channel, see if the other channel works better.

My guess would be the RF modulator is just low quality and introducing interference, or it is sending out a strong signal that is overpowering your TV. You could try adding an attenuator (from Radio Shack or similar) between the modulator and TV to see if it makes a difference.

If you have a VCR, you could try feeding the signal from your laptop into the VCR, then output the RF to your TV. Compare that with your modulator to see if there's a difference.

Maybe get a new TV (or a newer used TV off of Craigslist or similar)?

Anthony

[AndyPro]

That buzz is coming from a signal being sent to it that is "too white". Especially with an RF modulator, the video signal being sent form your computer really has to conform to broadcast standards. If something is whiter than white, the carrier gets overmodulated and that bleeds through to the audio portion of the filters and decoders inside your TV. White needs to be no higher than 100 IRE (I temporarily forget what IRE stands for!) and black no lower than 7.5 IRE or your TV can interpret it as a sync signal and thigns go all wonky.

The problem is that your computer doesn't give a hoot about IRE or broadcast standards at all. and it uses full gamut from 0 being black, to whatever really really white equals.

See if your video card has a setting for NTSC or something. Some do, and it will help control that.other than that, try turning your brightness down on the image you're outputting. so white is less white.


If neither of these work, it's possible hte TV is jsut going out the door. older sets do that when thier filters are so old they jsut dont do thier job properly anymore. Especially if ti was a cheaper set to begin with.

--Andy P

[liquidskin]

Thanks for the replies. I managed to get the sound under control by adjusting the brightness and contrast. All I have in my way now is the crappy picture. I just gotta get some test equipment to see if I can find the problem.

[zeroexecutioner]

On my bedroom PC running GBPVR, I have an older TV that I connect s-video out to composite and the picture is OK at 800x600. I have a laptop that I don't normally run S-video out on, but I hooked it up to the TV at the same resolution and it is much blurrier, and it has diagonal lines that appear to scroll from the top left to the bottom right of the screen. I've always assumed that it's just a limitation to the s-video out on my laptop with the older TV I have. But seeing this thread, I hooked the s-video out up to my LCD TV and had the same results. I think that it might be related to the video cards power/performance in my laptop.

By the way, the laptop is an IBM Thinkpad T30 1.6Ghz with the 8Mb ATI Radeon Mobility