Vertical shift when looped through DIGI machine?

[Chris Borjis]

it only happens on output right?

when you playback there should be no shift.

my digibeta only did this when I didn’t have genlock on itself and the multibridge extreme.

my betasp deck does it all the time though, and I’m not sure why.
but it plays back fine so I’m not really worried about it.

[Jimmy Brunger]

I just tried capturing from Editbox to Premiere looped through the Digibeta in the same way and it doesn’t shift. When I patch it in reverse and play the timeline TO editbox via DB machine it DOES shift. Very odd. Just to be clear, i’m not performing an export to tape or anything, just dragging in a clip into the timeline and hitting spacebar..then our editor on the Quantel captures my output.

The patching is as follows: –

SDI out of Decklink > patch bay > Digibeta input > digibeta output > patch bay > editbox SDI input + analogue audio de-embedded and taken out of Digibeta into Editbox via patch bay. Then Editbox SDI out > decklink SDI input via patchbay. PHEW!

How would I go about ‘genlocking’ my Decklink then? Sorry to sound a bit dumb.
We have a house sync generator, do I just plug it into that or does it need calibrating, etc?

*Production Studio Premium / *Combustion 3
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Win XP Pro SP2 / Intel P4 3GHz / 2GB RAM / GeForce FX5200 / DeckLink Pro / Sony BVM-20G1E / DVS SDI Clipstation / 110GB boot/80GB media/600GB RAID-0

[Bob Zelin]

how can you have a Quantel Edit Box, a Digi Beta VTR, patch bays, etc. and not have a house engineer to do this for you ? If I was the staff engineer, and you started messing with the rack cabling, I would kill you. Have the house engineer run black to the Blackmagic for you. Just plug it in – it does not need any “calibration”. You need to lock your system to the house sync gen.

Please remember that when you pass any signal thru a Sony VTR in E/E mode, the TBC in the VTR’s will shift the image vertically – when you actually record, and play back, there will be no vertical shift. However, if you intend to use the Sony VTR as a pass thru device (for up or down conversion), you will always have this shift – this has been the case since the linear days of editing.

Bob Zelin

[Chris Borjis]

bob my uvw-1800 (betasp) deck has always had a shift when recording (and i can see that blue-line near the vertical interval area) but it plays back fine.

is there a switch or item menu that would make it not shift during recording?

[Bob Zelin]

no – there is no way to get rid of this shift. This occurs with other Sony VTR’s as well, and has nothing to do with the Blackmagic product line.

If you had no Ref Vid going into your Beta 1800, you would see the vertical sync bar directly in the center of your screen, yet it would play back ok. With a ref signal, you get the shift that you see. For years, people have said “just pass it thru your VTR to accomplish X and Y” – but of course, you have the shift. (X and Y means anything from pseudo time base correction, to conversion of the input signal to other formats).

Bob Zelin

[Jimmy Brunger]

Hi Bob,

We don’t actually have an in-house engineer..we are a very small post-house and get independent tech guys in when something is needed in the machine room. We an in-house software/hardware PC guy, but he is not trained in the workings and cabling of the C.A.R.

I would get someone in to do this, but if it’s just a case of running my sync cable into a spare port on the house sync then I’ll do it and label it accordingly for when they are next in.

To clarify – I am not seeing any shift when going through the digiVTR from editbox>decklink, recorded output nor monitor input. I only see the shift (it is visible on monitor in Editbox AND on recorded output) when playing out to the editbox.

I only pass through the machine when outputting/capturing audio with my video, which is rare..but annoying when I do! But using the VTR seemed a better temporary option than buying a hardware SDI embed/de-embedder for several thousand. We will be overhauling the entire facility for HD soon, so I’m after a tempoary fix until then.

Sorry Bob, what is E/E mode?

*Production Studio Premium / *Combustion 3
————————————-
Win XP Pro SP2 / Intel P4 3GHz / 2GB RAM / GeForce FX5200 / DeckLink Pro / Sony BVM-20G1E / DVS SDI Clipstation / 110GB boot/80GB media/600GB RAID-0