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HD to SD and Ref signal problems

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Ben Scott
HD to SD and Ref signal problems
on Aug 11, 2008 at 10:36:59 am

been trying to figure this out for the past few weeks hopefully someone can help

We have been having real issues with HD to SD downconversion and cannot achieve a synchronous signal with SD, we can get an HD signal in synch however

This is a real problem as we need to use the Kona LH card card for downconversions to DigiBeta

We are feeding PAL HD1080i 50 and downconverting to 625i 25
We are working in following formats: HDV 1080, Prores422 HQ full 1080 and Prores422 HDV converted through firewire

A lot of different configurations have been tried out from a Textronix blackburst/trisync generator to the Kona card

Obviously the Digibeta Deck needs a blackburst SD ref signal and it appears the Kona card needs trisyc 1080i when working in HD (even when it is downconverting to SD on output)

We can get an HDcam deck to recieve signal fine and use this for downconverts in sync but this isnt really what we want as we dont always have access to the HDCAM player


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walter biscardi
Re: HD to SD and Ref signal problems
on Aug 11, 2008 at 12:21:15 pm

You should just pick up the AJA Gen 10 TriLevel Sync generator. It's around $350.

Funny enough, we have a VERY simple Horita SD sync generator and our UVW-1800 is just fine getting the downconverts from our Kona 3 all day. Seems the more expensive decks like the DigiBetas are much more sensitive to the proper sync on downconversion.

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

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Bob Zelin
Re: HD to SD and Ref signal problems
on Aug 11, 2008 at 11:42:30 pm

you want a simple answer - there IS no simple answer.
If you are operating at 1080i 29.97, the Kona will work with either NTSC black (525) or 1080i tri level sync (which can be easily obtained with the AJA GEN10, or your Tektronix IF YOU READ THE MANUAL becuase there are menus you have to set).

If you have an HD project that you are downconverting, and laying back to a Beta VTR, the Beta VTR wants to see NTSC Black (oops PAL black 625 - you are in Europe). The Kona will operate with this standard black signal as well IF YOU ARE NOT AT 23.98.

NOW, your Sony HD VTR is not like this. It not only wants 625 standard black or 1080i tri level sync, AND you have to go into the MENUS of the Sony HDCam VTR (the HDW-M2000 is Menu 331, for example), and tell the VTR if it is getting HD sync or SD sync.

Is this crazy, is this a pain in the ass - YOU BET IT IS. Every session is a new challange.

NOW, I am making a lot of assumptions here, because have never used a PAL system with the Kona, but I ASSUME that it works the same way an NTSC system will. SO, if you have your 1080 PAL job that is NOT at 23.98, and you are playing out at a normal frame rate (25 ?) for 1080i, and downconverting to Digi Beta SDI, then you can continue to use your nice boring PAL SD black gen (the Tektronix). I must urge you that the TEK has lots of menus that can be set differently and screw you up as well.

Remember that most people DO NOT OWN a tri level sync gen, and lock their HD Kona cards to 525 (or 625) black sync for almost everything (as long as they are not doing 23.98 jobs).

Bob Zelin




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Ben Scott
Re: HD to SD and Ref signal problems
on Aug 13, 2008 at 9:58:33 pm

got to say thanks to you 2 guys for answers

the reference signal being fed to kona is trisync level 1080 50i

the reference signal being fed to the SD digibeta deck is blackburst 625 PAL SD

the 2 signals are being fed from a tektronix generator that costs thousands and has 4 separate outputs set to the same house sync signal

we went in the tektronix generator and double checked the signal we were feeding the AJA was correct, then it got patched up correctly, it was 1080 trisync on the kona control panel

what we are finding is occasional initial sync and then a quick drift off that keeps drifting over time, causing lining of picture to change over time.

the advice from Kona didnt seem to address sync signals and instead was more to do with audio and video being off by one frame, they did however suggest trashing kona.plist file

I have a sneaky suspicion HDV is the culprit and is somehow corrupting settings somewhere (easy setups or Kona control panels) and not allowing us to properly set back. I have to say HDV has shown me how bad it really is in the past few weeks


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