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Video Ref issue? Help before I jump off a bridge!

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JmanFIVEK
Video Ref issue? Help before I jump off a bridge!
on Nov 7, 2007 at 12:19:56 pm

Hello,

I'm currently working on editing and laying to tape 13 episodes for a History Channel project here in Lithuania. It's a pretty massive project considering I have to deliver 5 tapes for each episode. 3 SD tapes and 2 HD tapes. The HD side of things is working without a hitch but I've been dealing with an issue on the SD side of things for weeks and I can't seem to solve the problem. Here's what's going on:

Here is a description of our setup:

We have a MacPro using a Kona 3 Card with the K3 breakout box. Our FCP sequence is 720p 23.98. Using the Kona Card we down-convert to 525i29.97. Next, we pass through a Harris DL-860 legalizer. Then it's on to our Sony DVW-A500 Digital betacam deck. This is a pretty straight forward set-up using standard equipment. But somewhere in this configuration, something is wrong and it's been driving me seriously batshit for weeks.

Here is a description of the problem:

After laying a sequence to tape, when I go back to QC it, digital artifacting will begin to appear. Sometimes this starts at the very beginning during the bars and tone. Sometimes this starts after 30 minutes into the tape. I have noticed that when it does start, it seems to continue until the end of the tape. Additionally, I notice the LTC and VITC readings get dropouts, and the the "tape condition" lights indicate problems. The signal looks totally fine during recording so I don't think it's a cable issue but just to make sure I bought all new cables, broke everything down, and reset it all up.

Right off the bat, everyone suggests the deck needs to be cleaned. The reason why I don't believe this is the issue is because:

1. I have been able to successfully lay dozens of sequences to tape under the same conditions without any trouble, before and after these symptoms appeared. The problem seems intermittent. Sometimes it will happen and sometimes it won't. Although lately, it seems to be happening every time.
2. The deck was just fully serviced.

So, the next thing suggested is a bad tape or a problem with playback. Other tapes made when this condition was not deciding to appear play just fine. I have tested handfuls of brand new unopened tapes and if the issue is happening, it happens on any tape I try to use.

One of the suggestions made by AJA was some sort of video signal feedback due to the "Video Ref" signal. So, to rule this out, I hooked up the AJA Gen10 blackburst generator. This didn't solve the problem. Nor did changing menu item #309 which tells the deck where to read the Video Ref signal from. Normally it should be able to just use the incoming SDI signal. So, maybe this isn't a video ref signal issue after all. I just don't know.

We also have an HDCam deck and when laying our sequences to the HDCam deck, this issue does not appear. This would lead me to believe the issue is not with the Kona Card or the legalizer but instead, something within the Digibeta deck.

I've spent weeks trying to solve this issue talking with support and engineers here in Lithuania and the States. It seems like, without seeing our setup, and the issue first hand, no one can make any additional suggestions. So I made a video which shows the symptoms and I have described above in as best detail as I can exactly what is happening. When the symptoms begin to appear, here is what it looks like on the monitor and the deck:

http://www.gardnerfilms.com/deckissue.mov

This is a Quicktime movie compressed with the h.264 codec. If you can't play it, you can use the latest quicktime (which is free) from: http://www.apple.com/quicktime/download

Does anyone happen to have any ideas before I jump off a bridge? :)

-jeremy morrison
jeremy@gardnerfilms.com


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glenn chan
Re: Video Ref issue? Help before I jump off a bridge!
on Nov 8, 2007 at 9:19:02 am

Perhaps the video reference signal is not clean/good??? (Though it seems like you checked for that.) The fun thing about that problem is that it tends to be intermittent and take a few to several minutes to rear its ugly head. Your symptoms seem like the deck not liking the reference signal (which gives dropouts and the channel condition flashing).

One way to check is to use another source for reference video. I think you can use a SD-SDI source with black picture as the reference source... e.g. throw a test pattern on the HDCAM, take SD-SDI off that, cable that into the ref. input on the dbeta.

Tapes need to be striped to the new reference video source. Make sure the stop button light is not blinking.

From what I remember, some of the switches on the deck also controls where ref. video is read from. Check the manual... it has a diagram showing the (perverse) logic. When you print to tape, it might be that the deck needs to grab reference from the video/SDI/kona (not the ref. input), and the Kona needs to grab reference from your reference source (e.g. the Aja Gen10 or some other source).

2- Did you check the error logger? What does it say?

3- (Maybe this'll help, maybe it won't)
It might be worth taking the legalizer out of the equation. Once you have your master printed to tape, you can enable pre-read and play/record the video onto itself through the legalizer.
**Pre-read is dangerous!! I would use an extra tape label/sticker and label the deck as having pre-read on.
**Not legalizing the video right off the bat is also dangerous... you don't want non-legalized masters going out before you forgot to do this.

4- Is confidence on or off? That might help rule out tape issues. If confidence is on you can spot problems with bad heads.


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JmanFIVEK
Re: Video Ref issue? Help before I jump off a bridge!
on Nov 8, 2007 at 2:29:53 pm

Perhaps the video reference signal is not clean/good??? (Though it seems like you checked for that.) The fun thing about that problem is that it tends to be intermittent and take a few to several minutes to rear its ugly head. Your symptoms seem like the deck not liking the reference signal (which gives dropouts and the channel condition flashing).

Thanks for the reply! The strange thing is, the HDCam deck is having no troubles with simply using the SDI video input from the Kona as the video reference signal. The other stange thing is that, on the dbeta with CONFI enabled, and menu item #105 turned on (to flash the STOP button if the video reference signal is out of phase), everything looks great.

One way to check is to use another source for reference video. I think you can use a SD-SDI source with black picture as the reference source... e.g. throw a test pattern on the HDCAM, take SD-SDI off that, cable that into the ref. input on the dbeta.

Tapes need to be striped to the new reference video source. Make sure the stop button light is not blinking.


This is a great suggestion. I will try this next. When you say the tape needs to be striped to the new reference video source, do you mean I have to black and code the beginning of the tape while the HDCam SDI out is connected to the dbeta VIDEO REF in?

From what I remember, some of the switches on the deck also controls where ref. video is read from. Check the manual... it has a diagram showing the (perverse) logic. When you print to tape, it might be that the deck needs to grab reference from the video/SDI/kona (not the ref. input), and the Kona needs to grab reference from your reference source (e.g. the Aja Gen10 or some other source).

Yeah, I've been checking and double-checking these settings and switches. Basically the OUT REF on the sub control panel needs to be set to REF and menu item #309 needs to be set to 1 in order for the deck to use the input video signal as the video reference.

2- Did you check the error logger? What does it say?

Error logger where exactly?

3- It might be worth taking the legalizer out of the equation. Once you have your master printed to tape, you can enable pre-read and play/record the video onto itself through the legalizer.

Actually I have tried this and I even called the manufacturer of the legalizer to ask about any known (or even possibly unknown issues) regarding video reference signals. They claim the unit simply takes it in and spits it out without any change. And, taking the legalizer out of the equation didn't make a difference in my testing.

4- Is confidence on or off? That might help rule out tape issues. If confidence is on you can spot problems with bad heads.

Today I have been testing with CONFI enabled. There appear to be no issues during the recording. The stop button doesn't flash, the LTC and VITC coding seems fine and the picture is perfect for the duration of the recording.

I went back and played a tape that has always played fine for me and low and behold, BLAM - the issue showed up.

So now I am thinking this is a playback issue and not a recording issue. The only way to confirm this is to play the tape on another dbeta deck. I'm in the process of tracking one down here in Lithuania.

Thanks a lot for the suggestions! :)


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glenn chan
Re: Video Ref issue? Help before I jump off a bridge!
on Nov 8, 2007 at 6:51:56 pm

[b]This is a great suggestion. I will try this next. When you say the tape needs to be striped to the new reference video source, do you mean I have to black and code the beginning of the tape while the HDCam SDI out is connected to the dbeta VIDEO REF in?[/b]
Yep.

2- The error logger can be accessed via:
Hitting the "entry" and "menu" buttons at the same time.

It doesn't report everything but some errors will get reported into the error logger.

[b]
So now I am thinking this is a playback issue and not a recording issue. The only way to confirm this is to play the tape on another dbeta deck.[/b]
I don't suppose your HDCAM deck has the digital betacam playback option.


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Tom Matthies
Re: Video Ref issue? Help before I jump off a bridge!
on Nov 9, 2007 at 5:03:27 pm

Total shot in the dark here but...
What reference are you feeding to the Kona 3 card? I notice that you are running a sequence at 23.98fps and downconverting to 29.97 to the Digibeta deck. In the Kona control panel, in the control tab, what is your genlock reference set to? Are you feeding tri-sync reference to the Kona by chance? Just for a test try to put the Kona 3 reference to "Freerun" and the Digibeta reference to incoming video and see of the problem clears up. I'm wondering of the Digibeta's servos are attempting to lock to an incorrect signal that they cannot handle and are thus causing all of the channel condition problems.
Worth a try...
Tom


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Richard Sanchez
Re: Video Ref issue? Help before I jump off a bridge!
on May 27, 2008 at 10:20:48 pm

I'm also working on a program for the History Channel, and we're using a near identical process to yours to lay off to D5 and Digi. What gives me pause, is we have set the parameters within the Harris 860 to clip RGB values at 700mv and below 0mv, and the same goes for our Pal Settings. When the ENC button is pressed in, it defaults to PAL settings for 1080psf 23.976. However, as we lay off the color bars, I notice that the blue bars are dulled into a dark purple. It doesn't happen when I lay off to the NTSC digibetas. Any advice with these Harris 860 settings would be appreciated. Thank you for your time!

Richard Sanchez
North Hollywood, CA

"We are the facilitators of our own creative evolution." - Bill Hicks


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