Any way to get rid of vertically moving horizonal bars in editing?

[Joe Barta iv]

Sounds like you got a 60 cycle hum in the video, probably from having a power source to close to the camera or crossing the line sending a video signal to a recorder. I haven’t seen a filter for this, look around it’s not an uncommon problem, someone has probably attempted one. If you or someone you know is really good in After Effects they could track the bar and and adjust levels accordingly.
Good luck.

Bars & Tone
SALUTE!

[Ben Mears]

Thanks for the reply Joe! At this point it seems like its going to be really hard to remove the lines, but I did find that if I scale the video up and show less of the background, it is less noticeable. Not ideal but I think it’ll be ok. (Tracking and adjusting in After Effects is a good idea, but I don’t think its worth the time and effort that would take, ha ha)

Thanks for the info about what could be causing the problem. When I was framing the shot I did not see the hum/moving bars and I only noticed them after I looked at the recording. How can I avoid this problem in the future?

-I use an AC adapter as a power source for the camera but this has never been an issue before. What kind of power source were you referring to? I was renting an office room for this shoot and I don’t think there were any power sources in it.

-What exactly do you mean by crossing the line sending a video signal to the recorder? I want to be sure I understand this so I can be aware of it for future shoots.

I’ve been shooting video for a long time and have never really experienced this problem before, so its a bit confusing to me.

Thanks a lot for your help! Hopefully you can answer these last couple questions so I don’t run into this issue again.

-Ben

[Joe Barta iv]

“-I use an AC adapter as a power source for the camera but this has never been an issue before. What kind of power source were you referring to?”

Who knows what may be running through the walls or floors. You might have been able to see the bars if your were using an external monitor. The rolling bars can also occur when your equipment is plugged into to two different ground sources. For example, your camera is plugged into one outlet and your audio mixer or recorder is plugged into another. The electrical grounds are out of phase with each other. Make sure all your connected audio and video equipment is getting its power from the same source.

“-What exactly do you mean by crossing the line sending a video signal to the recorder?”

Oops, crossing was the wrong word. If you have an electrical cord running “along side” your video or audio cables it can sometimes cause interference that can show up as the rolling bars. Make sure to keep parallel cords separated by at least 6-10 inches. If they have to cross, do it at a right angle or perpendicular.

Hope this helps for the next shoot.

Bars & Tone
SALUTE!

[Ben Mears]

Awesome, thanks a lot Joe! You’ve been extremely helpful.

It kind of seems like the room is to blame in this case, and for future shoots I’m now always going to shoot some test video and look at it before shooting the real footage, ha ha.

thanks again,

-Ben

[Joe Barta iv]

It just occurred to me that there might be another cause of the horizontal bars in your picture, frame rate and fluorescent lights.

If you shoot in a room lit by fluorescents and are using a frame rate other than 30fps or 60fps you can get a ghosting roll from the frequency of the lights being out of sync with the camera. It can also happen if you use a variable rate on your camera to take the roll out of a TV or computer monitor, that can throw it out of sync with the lights in the ceiling too.

Just on other thing we have to keep in mind when setting up for a simple shoot.

[Ben Mears]

Joe, I think you might’ve just hit the nail on the head!

I’m fairly certain the room I was shooting in had fluorescent lighting and the footage was shot at 23.976fps. That frame rate was a mistake because somebody else had used the camera before me, and left it set to 23.9, and I failed to change it. Definitely won’t be doing that again.

I’ve recently been shooting at 29.976fps and haven’t noticed any problem, but I don’t know if I was under fluorescent lights or not. Do you think that frame rate would give the rolling bars as well?

To be safe I think I’ll just start shooting everything at 30fps, ha ha. Thanks a lot for this info, you’ve been immensely helpful!

[Joe Barta iv]

Shooting at 29.97fps or 59.94fps (both broadcast standards) will work just fine, as well as 30fps or 60fps. They are close enough to the 60hz cycle is in the fluorescent lights, there is no perceivable effects. Sorry this didn’t hit me sooner.

Keep shooting!

[Ben Mears]

Actually, my mistake. I had gotten my footage mixed up and it looks like the footage with the horizontal bars was shot at 29.97fps. Back to being a bit confused, ha ha. Your info has definitely been helpful though and I think I’ll shoot everything at 30fps going forward.