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Kona 3 Output has Slight Horizontal flutter?

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ViperJPB
Kona 3 Output has Slight Horizontal flutter?
on Nov 11, 2007 at 7:57:19 am

I have only noticed this tonight (I have had the system since May) and now it's hugely distracting. It's very difficult to see in normal video footage but on higher contrast graphics (like Bold white text on dark backgrounds) there is a slight horizontal flutter that varies at different heights, almost like static or a fielding flutter, visible especially along the edges of the text and dark background. This flutter can be seen in video if examined closely. Difficult to see from a distance or with moving video. I am viewing on a SD JVC 15" Broadcast Monitor, about a foot away from me, via SDI from a Kona 3 breakout box. The flutter is visible on the output from any application, HD or SD, and SDI or composite on the same monitor (hard to tell if present on other low quality consumer TV). I am curious if this is normal? Is it an aspect of a high contrast image viewed on a broadcast tube based monitor? Or is it a problem with my Kona3 Card, breakout box, or even the broadcast monitor or the monitors SDI card? Maybe it's a cable issue? The effect can be seen on multiple projects and all projects are broadcast legal. I am using a Duel Quad Core Mac Pro with 9GB of RAM and 1.5TB Raid. Any help, suggestions, or answers welcome.


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walter biscardi
Re: Kona 3 Output has Slight Horizontal flutter?
on Nov 11, 2007 at 12:34:12 pm

You can see this on an interlaced monitor if your text is sitting on the wrong scan line for your format. Such as NTSC SD, your text should always land on an even line. With HD, it should land on an odd line.

Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.

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ViperJPB
Re: Kona 3 Output has Slight Horizontal flutter?
on Nov 11, 2007 at 5:48:00 pm

Thanks for the response.This happens in normal video though as well. Same effect, a horizontal flutter that looks like a line of static almost from right to left that flashes and distorts anything under it for that fraction of a second it flashes and then dissapears to flash in another area at a different horizontal height. Very difficult to see on video unless your close to the monitor and in high contrast areas...darkness seems to lesson the effect. I hope it's as simple as a field issue and natural occurence of a field based tube monitor...but the fact that it's not specific to text and it occurs regardless of placement on the screen and it distorts or flutters the video beneath it and it jumps around, I don't think it is. Could it be an electrical disturbance? The SDI cable sits on two DVI cables behind my computer monitors before emerging on the other side to go into the monitor? I'm going to go by some component cables today and run them from the Kona3 to a LCD monitor to see if it is the Kona's problem or the monitor. However that would only prove that the component outs of the Kona are fine and that it's either the SDI outs or the Broadcast monitor. Any other suggestions or help would be greatly appreciated.


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JeremyG
Re: Kona 3 Output has Slight Horizontal flutter?
on Nov 11, 2007 at 8:11:19 pm

If you export a Quicktime and watch it on the computer, does it happen in the quicktime?

Just trying to rule out a software or hardware issue.


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ViperJPB
Re: Kona 3 Output has Slight Horizontal flutter?
on Nov 11, 2007 at 8:29:07 pm

It is not visible on the computer's LCD screen at all, only on the output from the Kona on the broadcast monitor. Every piece of software that can utilize the kona output to the broadcast monitor has the same effect in the external monitor with any and all footage and formats(After Effects, Final Cut, Combustion, Color). I hooked up an external Canopus box that gets fed via FireWire and sends an S-video connection to the same broadcast monitor, and it shows the same effect. That makes me think its the monitor and not the Kona. I'm going to buy some bnc cables this afternoon and wire up an HD LCD via component from the Kona to make sure. I will re-post when I know more.


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ViperJPB
Re: Kona 3 Output has Slight Horizontal flutter?
on Nov 11, 2007 at 11:36:04 pm

Okay I have now connected an LCD monitor to the Kona via Component and there is no problem whatsoever! When sending SDI from the Kona card or S-Video from the Canopus box to the broadcast monitor you can see the same subtle horizontal line flutter (probably a pixel thick almost like a field or static line). This line pops in and out in a fraction of a second and always at varying heights. I think I can see it on my consumer TV as well..but not as pronounce. So it's not the Kona card because it is visible through the canopus box as well. So it is surely the Broadcast monitor, possibly a minute artifact of the tube's gun? I'm now not sure if it is a problem with the monitor or a problem in that my eyes are to good. Barely anyone can see it! And if someone does they only see it once. If you sit at a normal viewing distance, instead of the 1 ft distance at my desk, it's not noticeable. Does anyone have a 15" JVC Broadcast monitor with SDI card and can sit really close and look at high contrast text on black and tell me if you see the same? In normal video footage, it is very difficult to see and has to be sitting still and again a high contrast difference area (White object with dark backing). I'm wondering if I'm to much of a perfectionist and just have an eagle eye and only recently noticed this possible natural side effect of a CRT tube based broadcast monitor?


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JeremyG
Re: Kona 3 Output has Slight Horizontal flutter?
on Nov 12, 2007 at 12:01:21 am

[ViperJPB] "I'm wondering if I'm to much of a perfectionist and just have an eagle eye and only recently noticed this possible natural side effect of a CRT tube based broadcast monitor? "

I appreciate this attention to detail, but I really think you are staring too hard. All CRTs are full of artifacts, one every 60th of a second in NTSC. If you don't see it in Quicktime and it's not something that is overly pronounced, I think it's going to be okay. SIt back, relax and enjoy the show. It sounds to me like you are psyching yourself out a bit. If you have to 'think' that you can see it on another monitor, that tells me your brain is doing some dandy work.

Jeremy


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ViperJPB
Re: Kona 3 Output has Slight Horizontal flutter?
on Nov 12, 2007 at 12:12:20 am

Okay that was funny and embarrassing all at the same time. Yeah I think your right. I am probably seeing exactly that and that is exactly the nature of a CRT tube. I'm going to check out the same image at a studio of a friend of mine who has a similar setup to varify my craziness. Thanks for your help and I will re-post when I know my diagnoses. :)


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JeremyG
Re: Kona 3 Output has Slight Horizontal flutter?
on Nov 12, 2007 at 12:14:56 am

Please keep me informed.

Jeremy


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ken hon
Re: Kona 3 Output has Slight Horizontal flutter?
on Nov 12, 2007 at 8:42:20 am

Aloha,

One other thing to consider is that the conversion from HD to SD color space sometimes creates illegal settings. We had a set of scenes that caused viewing problems during SD downconvert and found that the whites in a small silver of overexposed sky were over 110 IRE in SD, but right at 100 IRE in HD. Don't know if this is your problem, but it could be with the white background.


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