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1080p24 to NTSC DigiBeta
I have an HD sequence 1080psf23.98 (ProRes 422) that I would like to layoff to DigiBeta NTSC letterbox with precise timecode. I’m using a KONA LHe card, which works beautifully for the downconversion and adding pulldown.
For the same project, I also laid off some SD versions that were cut at NTSC 23.98. FCP Vid out was set to NTSC 8bit, deck control @ 29.97, etc. Everything worked fine for that.
But now when I’m trying to make an 1080p to SD downconvert it’s not working properly. My FCP Video output is set to KONA 1080p23.98, deck control set to 29.97, and I’m using the KONA card to downconvert to NTSC. It looks great on KONA Output, but when monitoring the DigiBeta Output, the screen is split, like when the sync is off – and when I check the DigiBeta tape playback – the picture loooks fine, but the audio channel condition goes red.
I’ve been using 29.97 Reference for the KONA card and the NTSC deck. Should I be using 23.98 Reference? How would that work when laying off to 29.97?
I also tried switching my FCP Vid Out to KONA 1080i29.97 – and it plays back fine during normal output, but when trying to layoff to tape, I get dropped frames, which is odd, because I know the drives are fast enough, and it only happens during Edit to Tape.
What’s the proper configuration for what I’m trying to do?
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9 Replies
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Since it looks good on the Kona output, it seems to me your deck is setup wrong. Are you sure the ref is set for external and not incoming video?
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Hmm. Not sure about that.
I’m always feeding the deck NTSC, but when the KONA format is 525-29.97, everything’s great, when KONA is at 23.98 and the SDI is a downconvert signal, that’s when the Digi output goes split screen.
Does that sound like a internal deck setting? We’ve used the deck for years and never had to change a setting, but we’ve usually been doing straight up NTSC.
I probably should have mentioned that this is all going through an HD-SDI router, too.
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Are you monitoring SD at your station as well and the output looks good? If the outputs of the SDI are good in HD and SD and it’s only after the signal reaches the deck then the deck is having trouble with whatever it’s receiving. Does that make sense? Obviously something is setup wrong.
Jeremy
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Thanks, Jeremy.
That makes sense, but I’m wondering if the deck is confused because my KONA card is receiving 29.97 reference, but working in 23.98, adding pulldown, then outputting 29.97. Should the KONA be able to maintain proper sync in that scenario? If the KONA switches to 29.97 (1080 or 525), all is well.
(our facility has been pretty stable, so it’s been a while since I’ve had to deal with ref sync issues or deck settings, and I’m a little rusty on these kind of things, especially with tri-Level sync involved…)
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Tri-level is built for 23.98. What kind of sync generator do you have?
If you can send tri-level to the Kona and regular old blackburst to the deck, you should be good. Although if you take both off of sync and tell the deck to time to the incoming SDI video, your problem might go away as well. That way there’s no confusion.
Jeremy
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It’s a Tektronix SPG 422- but I’m not sure if it’s configured properly, as when I patch “tri-level sync” to my KONA, it still says the Ref in is 525i29.97.
I’ll put in a call to our engineer who set things up originally.
Thanks for your help, J.
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No worries.
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To follow up…
Our engineer said that you can’t have 2 different kinds of sync at the same time, which makes sense.
He said the thing to do was to put the KONA, (which is at 23.98) into FREE RUN mode, and then set the NTSC DECK sync to VID INPUT, which will take it’s sync from the KONA’s downconverted NTSC signal and all will be fine.
It worked like a charm.
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There ya go. Locking the deck to incoming video is key in that situation.
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