White Line in Video Output

[wrems]

Does anyone have an idea why I get a little white/grey bar through my recordings? It's about in the middle and runs horizontal across the image. It’s a faint line but annoying to look at. See attached photos.

[bcjenkins]

What's your source and connections? What type of tuner? If PCI what other cards do you have in adjacent slots?

B

[Fastrack]

Originally Posted by wrems

Does anyone have an idea why I get a little white/grey bar through my recordings? It's about in the middle and runs horizontal across the image. It’s a faint line but annoying to look at. See attached photos.

I'm gonna take a shot in the dark, but I bet it's a ground loop.

If you don't have anything playing and you turn up your stereo/speakers do you hear a 60hz hum? And if you do, and you unscrew the cable from the PC does it stop?

[stevech]

ground loops are usually rolling vertically, slowly, because AC power is 60Hz and (USA) TV is 59.x Hz. And the bar tends to be about 20% of the picture height.

A weak hum bar will still roll but might look skinnier.

I get a huge hum bar on my TV's AUX-in RCA jack for composite video, when that feed runs a long way to a PC in the garage - and it is plugged into a the opposite AC phase. The solution I use is (bad) to lift the PC power cord's ground pin, to eliminate the hum by floating the PC's chassis. Have to do this with any periperals that have a 3-wire AC plug too, or lift the ground for the whole plug strip that feeds all these devices.

A "Hum-bucker" transformer won't fix ground loops. It will fix induced AC hum.

But this may be a tangent to the OP's problem.

Can also be a weak TV signal in another city if it's off the cable or antenna.

[wrems]

Originally Posted by bcjenkins

What's your source and connections? What type of tuner? If PCI what other cards do you have in adjacent slots?

B

I have SD Comcast cable with a Hauppauge MCE 500 tuner card with no adjacent cards in PCI slots. I use an MVP for video output but the line is being recorded from the source.

[wrems]

Originally Posted by Fastrack

I'm gonna take a shot in the dark, but I bet it's a ground loop.

If you don't have anything playing and you turn up your stereo/speakers do you hear a 60hz hum? And if you do, and you unscrew the cable from the PC does it stop?

I tried this... I really don't hear a difference. There is a slight hum regardless of being connected to cable or not. It's very slight.

[wrems]

Originally Posted by stevech

The solution I use is (bad) to lift the PC power cord's ground pin, to eliminate the hum by floating the PC's chassis. Have to do this with any periperals that have a 3-wire AC plug too, or lift the ground for the whole plug strip that feeds all these devices.

Not exactly sure what you mean by this. Could you elaborate?

[Fastrack]

Originally Posted by wrems

Not exactly sure what you mean by this. Could you elaborate?

He is speaking of the same thing I am. Do you have any other grounded equipment?

These lines appear because the 2 grounds (cable and house wiring are trying to find a common ground point), and the ground mV actually travels along the sheilding on the video cables.

If you TV for example also has a cable input - and your computer is also connected to your tv it can also cause a "ground loop"

Ben

[wrems]

How do ensure that all my equipment is grounded? As far as I know it is. I really don’t know too much about this subject. I'm just trying to fix the lines from appearing in my video output.

[bcjenkins]

If you live in a house take a look at the point where the cable connection comes in. Make sure they have put a grounding block on it.

[Fastrack]

Originally Posted by wrems

How do ensure that all my equipment is grounded? As far as I know it is. I really don’t know too much about this subject. I'm just trying to fix the lines from appearing in my video output.

bcjenkins - you are correct and most cable systems are grounded when entering the house, but if it not properly tied in with the electrical ground then the loop appears.

wrems - the easiest thing to do is remove ALL cable connections from your equipment. If the lines disappear it's a ground loop caused by the cable company, you have a few options:

1) Call the cable company and ask them if they have any idea what a ground loop is and do they fix it - should be covered - no charge to you. I have heard of some companies fixing this.

2) Buy a ground loop isolator - these go on the line before connecting to your equipment they lift the ground on the cable to prevent the loop:
http://www.21best.com/21_best/electr...ale_.html#CATV

3) Lift the ground on the PC - ie use a cheater plug. Not the best solution as if the device malifunctions you could get a big shock. If you do go this route it's best to plug the device that you removed the ground from into a GFCI outlet - which will protect the human touching the equipment from getting a large shock.

#1 & 2 are the ideal solutions, but you must test the theory first buy disconnecting the incoming cable from the devices. You can also get a ground loop from a Satellite, but it's much more rare.

[bcjenkins]

Also, you might want to try a different PCI slot. I have heard of issues being caused by capacitors, etc.

[GKusnick]

Originally Posted by wrems

...but the line is being recorded from the source.

I'm confused. Your thread title says "white line in video output" but now you seem to be saying it's in the input. What steps have you taken to narrow down the point at which the defect gets introduced into the image?

For instance, does the defect appear when tuning channels directly using the Hauppauge software, without going through Sage? Does it appear on all channels or just some? If you hook the coax directly to your TV, is the defect present then? If you hook up a composite video source (say a camera or DVD player) to the RCA jack on your capture card, does the defect appear in that image? If you take the recorded files to another machine and play them back using WMP, is the defect still present?

Before you go juggling cards around or chasing off after ground loops, you first ought to nail down whether the problem originates during playback or recording, or whether it's already present in your cable signal before you record. Maybe you've done some of this troubleshooting aleady, but if so it's not clear (to me anyway) how much.

[wrems]

You’re right I have been confusing. Sorry about that. I live in an appt so I can’t check where the source comes in.

It seems to me that the line is being recorded at the source. Since when I play it back on any computer I get the little white line. Attached is another example of an inconsistent problem I get again only on certain channels, and at certain times. This sample is bluntly more obvious and seems to start at bottom of the screen and work its way up. Sometimes in parallel pairs, and sometimes just a single line. It is intermittent, and other times all I get is a few white horizontal flicks like horizontal snow all over the screen. It's not always there, and only visible sometimes. It's really inconsistent. This too doesn’t appear directly from Comcast, only when recorded through my tuner card.

Originally Posted by GKusnick

does the defect appear when tuning channels directly using the Hauppauge software, without going through Sage?

Haven’t tested this yet. I will test this.

Originally Posted by GKusnick

Does it appear on all channels or just some?

Only appears on some stations, and not all the time??

Originally Posted by GKusnick

If you hook the coax directly to your TV, is the defect present then?

No.

Originally Posted by GKusnick

If you hook up a composite video source (say a camera or DVD player) to the RCA jack on your capture card, does the defect appear in that image?

Haven’t tested this. I will try this too.

Originally Posted by GKusnick

If you take the recorded files to another machine and play them back using WMP, is the defect still present?

Yes

[GKusnick]

Since it doesn't appear on your TV, but does appear in the recorded files, it sounds to me like the defect is originating inside the PVR500. This could be caused by grounding issues or interference from neighboring cards as already discussed, or possibly by some sort of crosstalk between the two tuners of the PVR500 itself. Does the pattern of interference on one tuner change when you change the channel on the other tuner? You can test this by viewing live TV on one tuner and then setting manual recordings on various other channels at the same time.

There'a been some discussion in the Hardware section of the forum of image quality issues with some batches of PVR500. I apparently have two of the good ones, but other folks haven't been so lucky.

[AWS]

Wrems:
Has there been any solution to your problem? I'm having the same exact issue.

Thanks.
AWS

[wrems]

Originally Posted by AWS

Wrems:
Has there been any solution to your problem? I'm having the same exact issue.

Thanks.
AWS

Actually no. It is still the same. I haven’t been able to devote too much time lately in tracking the culprit down. Basically, I'm just living with it for now until I ante up the money to bring in a digital cable box, or Sat TV.

I think the signal coming in is terrible, I notice a huge difference in quality switching from regular cable (no Sage) and then watching TV through Sage. Sage does a really nice job of cleaning the signal of most of the garbage. Overall, the picture still isn’t very good, I think my solution lies in a digital STB.

The thing I haven’t figured out (nor taken the time to find out) is whether I can purchase a digital cable box to use with Comcast so I don’t have to pay them rental fees for one with DVR capabilities. All I need is the vanilla box to clean the signal coming into Sage.

[Razillian]

Would you happen to have a cable splitter sitting back among a mess of wires prior to going into the PVR500? Only reason I ask is I was seeing the same thing on my nVidia dual tuner and it seemed to have gotten much better after I raised the splitter up from the rest of the cabling mess and connected the ground screw via wire to a solid ground (computer case).

What had lead me to try that was that if I plugged the cable directly into the card and bypassed the splitter the white line did not appear (or atleast as much).

[AWS]

I have a splitter at my cable source as it comes out of the ground and into my house; that 2-way splitter is grounded to a pretty good-sized wire "plugged" into the ground (outside of house). One 75-Ohm cable goes to my living room where I have my one and one SageTV box. The other end goes to my cable modem and gear up in my office.

I then have another 2-way splitter in the living room off the primary lead that goes into each PVR-350 (two of them). I've added a ground wire from that 2-way splitter to the ground prong on the wall plug of my line conditioner (wall --> line conditioner --> surge supressor). So I know I'm tapping into the "same ground" as everything else in the room (TV, computer, amp, sub). That took away about 50% of my original hum.

I then added a grounding wire, experimenting here, attached to where the mounting bracket of the sound card attaches to the sound card itself down to a bare metal screw that attaches to my powersupply. That didn't do anything.

So then I tried grounding out the TV (does NOT have a third, grounding prong, in the plug) to my other gear but still no change.

I do get a horizontal bar that slowly scrolls up the screen. And I also get a pretty loud hum coming across my subwoofer - not my speakers, just my subwoofer. I've tried grounding all components together but still no luck.

At this point I think it might be the Creative Audigy 2 ZS card I have in there; however, I do have two of the same cards and have the same problem when using either card. So it might not be the card (hardware) but rather a driver issue ??? Grasping here. When the PC is booting up and still in DOS mode there is no grounding loop hum but as soon as Windows Vista initializes the card then I get the hum. I do have on-board audio so I guess that can be my next step to take tonight to see if using on-board audio causes the same problem.

[jtshea]

I have a similar issue. It appears on analog cable 17, 18, 19 and 24. My white bars are thicker and there are two of them. I see the problem on my ATI Theater 650 tuner, but not on my Hauppauge PVR-150. I've tried most of the suggestions above, except for checking out the grounding (which I will do tonight). One other difference with my problem, is that the white bars seem to slide up and down randomly sort of like an audio level meter. It's not just a slow crawl in one direction.