View Full Version : FCP What are those striped lines moving in the white areas?


Todd Coffman
September 11th, 2005, 07:47 PM
I am editing some video and there are these lines moving across the canvas in the white areas. I assume they have something to do with the light being too bright, but I'm not sure. Can I use color correction to address that? and also is there and auto color correction tool or do I have to adjust it manually?

Zach Mull
September 11th, 2005, 09:41 PM
You are correct. Those zebra lines are from the Range Check function. Depending on the setting they either indicate whites above 100%, oversaturated colors or both. If you apply the broadcast safe filter and leave it on the default settings, it will reign all those in. As long as your image looks good to you, I don't think it particularly matters whether you have those high whites or saturated colors unless you are delivering for broadcast.

Stephanie Wilson
September 12th, 2005, 12:11 AM
I am editing some video and there are these lines moving across the canvas in the white areas. I assume they have something to do with the light being too bright, but I'm not sure. Can I use color correction to address that? and also is there and auto color correction tool or do I have to adjust it manually?

Dear Todd,

Yes, the previous post is correct. These are called zebra bars and they indicate when you have reached a certain level of IRE. Don't know where you have your level indicators set but you should be fine for broadcast until you reach 125% or superwhite. Just to reassure you, these zebra bars will not show up when you finally play your tape.

That's all I know.....

Steph

Zach Mull
September 12th, 2005, 12:53 AM
There is no such thing as IRE when you're working in digital video, and in FCP's case, 101% is the start of superwhite. It uses its own percentage units in the scopes, with 0% as black and 100% as the brightest normal white. But Stephanie is right about the final tape. If you aren't going to broadcast it and don't care to color correct, you can just turn the range check off in the View menu.

Stephanie Wilson
September 12th, 2005, 01:30 AM
There is no such thing as IRE when you're working in digital video, and in FCP's case, 101% is the start of superwhite. It uses its own percentage units in the scopes, with 0% as black and 100% as the brightest normal white. But Stephanie is right about the final tape. If you aren't going to broadcast it and don't care to color correct, you can just turn the range check off in the View menu.

Thanks Zach,

Did a little research and learned alot or at least as much as my brain is capable of learning at 12:30pm. Perhaps my misinformation stems from my shooting with a digital camera for a network with analog satelitte tranmission capability. The engineers were still always looking at the white level.

Anyhoo, I found this link that may be helpful to all....
http://www.kenstone.net/fcp_homepage/video_levels_nattress.html

Best,

Steph

Greg Boston
September 12th, 2005, 06:54 AM
Thanks Zach,

Did a little research and learned alot or at least as much as my brain is capable of learning at 12:30pm. Perhaps my misinformation stems from my shooting with a digital camera for a network with analog satelitte tranmission capability. The engineers were still always looking at the white level.

Anyhoo, I found this link that may be helpful to all....
http://www.kenstone.net/fcp_homepage/video_levels_nattress.html

Best,

Steph

Exactly. Although there is no such thing as IRE levels in digital video, we have to allow for how those digital signals will map into the analog realm for broadcast. Until the current NTSC analog transmission system goes away completely, this will be an issue. That's why it is important to keep the 8 bit RGB values between 17 and 235. Those values will keep you 'broadcast safe'.

=gb=

Glenn Chan
September 12th, 2005, 07:45 AM
100% as the brightest normal white
To be assinine, I will point out that many cameras will record superwhites (values above digital white level, or 100% on FCP's waveform monitor).

Todd: The 3-way CC has an automatic function. That does one thing (it'll compress everything).

The broadcast safe filter does something else (it compresses the highlights).

Whichever looks better, is better.

You can check out either filter on a color gradient. Make a test sequence and change it to process RGB as superwhite (under sequence settings). 255 255 255 RGB will go to 110% (FCP) instead of 100% with that setting. Normally you don't want it on.

Zach Mull
September 12th, 2005, 10:24 AM
Glenn, I don't think it's asinine to point that out. If the cameras didn't record superwhite then we wouldn't even have this thread, would we? Do you know why they record this high? Do ATSC standards or some other digital format use that superwhite range or is it helpful if your final output is for web or some other computer delivery? I can't figure out what good it is because on all the DV cameras I've used, those superwhites are just clipped. I can never get any detail out of them. Can pro cameras record detail in this range?

Stephanie, what did your engineer do if you came back with high white levels? I've read your other posts and figured you would know about broadcast (I know nothing about it). Did you always have to go through post with hot footage before you could do a satellite feed or did you take the whites down on the analog output with hardware filters or some such thing?

Todd Coffman
September 12th, 2005, 06:25 PM
This has all been very helpful information. I am most certainly a Newbi in FCP (stepping up from Pinnacle Studio on my PC), so I am trying to soak in a lot.
Thanks again for the help.

Coffkid