Bit of a long story but please stick with me... About a year ago I bought an 'S-video + headphone to RCA cable' and I got quite a bit of use out of it streaming video from my laptop to the TV. My only problem was that on my TV I got alternating light and dark lines scrolling from the bottom to the top of the screen. It only happened with my TV though, when streaming onto various friend's TV's there were no lines so I figured it was just because my TV was old. Anyway, a few weeks ago now I got a new 37" LCD TV with VGA input and I picked up a VGA cable to stream to the new TV in hi-def, but was frustrated to find that the lines were still there. They're actually worse now because the resolution is better and they're more obvious. I've tried messing with all the settings I can find but cant figure out the cause of the problem. I dont think its electrical interference either because the cable isnt near anything electronic and I've even tried unplugging most of the electrical appliances in the house. I'm really at wits end here. I have a beautiful HD picture ruined by these scrolling lines that are nearly impossible to ignore. If anyone can suggest anything at all to try I'd greatly appreciate it.
They may be "hanover bars" .. horizontal banding caused by the wrong phasing of the chroma subcarrier.. try outputting interlaced video.. vlc is probably your best player to experiment with settings.
Thanks for the suggestion but its not a problem with just video. All output to the TV has the slowly scrolling lines, regardless of the source. It could be a game, video, even web browsing. The lines are completely unaffected. I did try messing with VLC settings anyway, but it didn't have any effect. Edit: I tried upgrading my graphics drivers, now the lines scroll quickly. Lol
I'm still trying to work out exactly what you mean by "slowly scrolling lines" .. is the picture rolling, or is it a stable picture with like bands of noise.. if so does the tv do this on the composite av signal.. or only with this laptop on the s-video out. If that's the case I suspect there is a fault somewhere in the actual video encoder on the laptop board itself. very hard to diagnose without actually seeing it
The picture is stable with light and dark lines moving from the bottom of the screen to the top. I tried taking a picture of it but it doesn't photograph very well. The best picture I was able to get was this one http://img220.imageshack.us/my.php?image=sta70964.jpg You can see the dark part of the line on the right of the screen, about even with the sandworm's lowest eye. What you cant see is that below that dark part there is a light bar, and then several smaller and dimmer light and dark bars below that one as well. I know it doesn't look like much in the picture, but it is far more obvious and annoying when viewing it in person. As for when we see this, it happens when streaming from either my PC or laptop, with both s-video and VGA. My girlfriend's laptop does not have this problem. And when I bring my laptop over to friend's houses everything works perfectly as well. So basically both my computers have this identical problem with both my TV's, but they do not have the problem on any other TV's I've tested with (at least 6 different ones) and other people's computers do not have the problem on either of my TV's either.
That is mains noise .. somewhere something is causing a large amount of about 50 or 60Hz electromagnetic interference OR.. and this is a good one... the power source you have the pc and laptop into is on a different ring main.. with possibly live/neutral reversed... causing a grounding loop.. same thing as audio hum. I would start checking the wiring to the power sockets concerned, and different cables. Really.. those are the only two options here.
Alright! Thank you! Its not exactly fixed but at least I know what the problem is! If the laptop is plugged in then I get the scrolling lines, but when it's running off battery it's perfect. I tested it on several other outlets and the lines reappear, though moving at different speeds or in different directions (sometimes up, sometimes down) I guess the power in the whole house is messed up. So that just leaves the question of why other laptops that people bring over work fine. Maybe their power supply bricks can filter out the interference? My laptop power brick is a cheapo lite-on brand so I'd gladly buy a better one if that would finally fix this stupid problem. Edit: Scratch the new power brick. I did some research on ground feedback loops and started to experiment with unplugging wires. Figured out that the loop was going out through the cable connection (HDMI to the cable box to coax cable) So I've ordered a coaxial ground isolator from amazon. I'll post when it comes and let you know if it works.
