Weird horizontal lines with PV-155 card.

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Posts: 18
Joined: Mon Jan 24, 2011 7:11 am

Weird horizontal lines with PV-155 card.

Post by erpo41 » Fri Apr 04, 2014 3:16 am

Here's the picture.

Here's more information about my setup.

CPU: Intel Core i3-3220
OS: Ubuntu 12.04 LTS
Zoneminder: 1.24 (I think. Might be 1.25.)
bttv module options: card=77,77,77,77 (per manufacturer recommendation)
Card model: PV-155
Card URL:
Card interface: PCI
bt878a chips: 4
Inputs supported: 16
Inputs in use: 13
Color mode: YUV422p
Captures per frame: 1

Troubleshooting steps performed:
  • Setting captures per frame to 2 decreases the artifacts somewhat.
  • Setting captures per frame to 3 almost eliminates the artifacts. At this setting I see them perhaps every four seconds or so.
  • Running memtest86 overnight did not turn up any errors.
  • Replacing the PV-155 card with a spare of exactly the same model did not fix the problem.
  • Applying heat sinks to the bt878a chips did not fix the problem.
  • Moving the PV-155 card to a different PCI slot did not fix the problem.
I've read that horizontal lines through the picture can be a symptom of PCI bus saturation, but I can't see how that would be happening here. By my math:

640x480 pixels per frame * 2 bytes per pixel * 2.5 frames per second * 13 inputs = 19968000 bytes per second = approx 20MB/sec. My standard 32-bit, 33MHz PCI bus should be capable of transporting 133MB/sec, and the machine isn't doing anything other than being a zoneminder server.

Any ideas about what might be causing this problem?


Posts: 943
Joined: Wed Apr 02, 2008 12:04 am

Re: Weird horizontal lines with PV-155 card.

Post by bb99 » Sat Apr 05, 2014 1:43 pm

I've seen this issue twice. Once it was a bad power supply for the camera and the second was a bad ballast in a florescent light fixture. Both times cleaning up the power to the cameras was the fix.

Just curious: Did you try BGR24 for a capture palette? (Keep in mind that all monitors using a single chip must be set up exactly the same)

Posts: 18
Joined: Mon Jan 24, 2011 7:11 am

Re: Weird horizontal lines with PV-155 card.

Post by erpo41 » Sat Apr 05, 2014 6:09 pm

I'm happy to have something else to try regarding the camera power supplies, so I'll test that on Monday.

I should have mentioned that these problems started after I removed three Hauppauge ImpactVCB 188 cards (each with a single bt878a chip and 4 BNC inputs, for a total of 12 inputs) and installed the PV-155 so I could add a 13th camera. Prior to switching out capture cards, I did not have this problem.

The thing that makes me suspicious is that the "problem lines" aren't random noise. They seem to be coming from other inputs.

Check out the areas outlined in red:

The capture in the top right corner looks normal, but the capture in the bottom left corner has lines. If you look closely at the lines, you'll see that they are lines from the picture in the top right corner.

At first I though it could be that the bt878a chip was being instructed to reuse the same memory region for capturing multiple inputs and that PCI bus transfers were failing for some video lines causing old video data to show through, but now that I look more closely, the pictures aren't aligned, so maybe that's not what's happening.

Posts: 18
Joined: Mon Jan 24, 2011 7:11 am

Re: Weird horizontal lines with PV-155 card.

Post by erpo41 » Fri Apr 11, 2014 1:52 am

Changing out the camera power supplies did not fix it.
Switching to the BGR24 capture palette did not fix it.

Posts: 195
Joined: Thu Oct 11, 2007 5:10 am

Re: Weird horizontal lines with PV-155 card.

Post by haus » Sat May 24, 2014 6:23 pm

I get this when captures_per_frame and my frame rate for each cam is too high on a card with a shared chip, and it is massively exacerbated when running anything over 320x240. I recommend going to a card or cards that have one BT878 chip per camera. Those shared chip cards that advertise 30fps are splitting it between all 4 inputs. I have one such card that has two inputs in use and I have to run 320x240, 2 captures per frame, and limit ZM to 3fps or I get either lines like you do or I see the wrong image on the camera at times. If I added two more cameras to that card I'd have to halve the frame rate to 1.5fps.

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