ProTools Machine Control and PAL DBC problem

[quadraphonics]

All,
I am hoping that someone here can help me out with an on going issue we are having with Pro Tools machine control interfacing with a PAL Sony DVW-500.

When using our ProTools v7.3.1 system connected using machine control (LTC, not serial), the PAL DBC plays back in a jerky and inconsistent and will not go into record.

When using our ProTools v7.2 system, the PAL DBC causes audio glitches on all four channels at each out point - similar to a tape concealment error.

We only have the one PAL DBC deck to check this against. The machine control works well for all of our HD and NTSC machines.

Does anyone have any thoughts as to what might be causing this??

Randall

[Neil Whippey]

I had a glitching problem recently with an SRW 5500 deck. We solved it in the end when we discovered that that deck was particularly sensitive to reference (our client was waiting for like 2 hours to do the layback - embarrassing!!!). Our Pro Tools rig is in a different location to the deck, but both got fed reference from the same place. The difference in distance caused this deck in particular to glitch on insert as the references weren't lining up due to fractional timing differences. Could be the case for your DVW????

I ended up having a long conversation with the Tech at HHB Scrub in london, who basically supply Pro Tools support to pretty much every London post house, and he said that nearly every time (in his experience) you get a layback machine control glitch it will be to do with reference unless there is a problem with the deck. This is because it is one of the only things that is slightly different from post house to post house. Do you guys have a Pal Black and burst generator?

Neil

[quadraphonics]

Thanks..I both cases the Pro Tools units are clocking via AES from the PAL DBC. The PAL DBC is getting clock reference from our Brainstorm unit.

Randall

Originally Posted by Neil Whippey

I had a glitching problem recently with an SRW 5500 deck. We solved it in the end when we discovered that that deck was particularly sensitive to reference (our client was waiting for like 2 hours to do the layback - embarrassing!!!). Our Pro Tools rig is in a different location to the deck, but both got fed reference from the same place. The difference in distance caused this deck in particular to glitch on insert as the references weren't lining up due to fractional timing differences. Could be the case for your DVW????

I ended up having a long conversation with the Tech at HHB Scrub in london, who basically supply Pro Tools support to pretty much every London post house, and he said that nearly every time (in his experience) you get a layback machine control glitch it will be to do with reference unless there is a problem with the deck. This is because it is one of the only things that is slightly different from post house to post house. Do you guys have a Pal Black and burst generator?

Neil

[musikwerks]

I would try using the brainstorm to supply reference to PT as well. That way the DB and Tools have the same constant reference. It's possible that PT is losing reference for a tiny amount of time when the DB deck drops into and out of edit mode.

[quadraphonics]

I believe that we have tried that, but I will definitely try it again.
Thanks,
Randall

Originally Posted by musikwerks

I would try using the brainstorm to supply reference to PT as well. That way the DB and Tools have the same constant reference. It's possible that PT is losing reference for a tiny amount of time when the DB deck drops into and out of edit mode.

[TVPostSound]

Thanks..I both cases the Pro Tools units are clocking via AES from the PAL DBC. The PAL DBC is getting clock reference from our Brainstorm unit.

Yes, thats your problem. You have to clock BOTH Protools, and the DBC to common
VIDEO BLACKBURST. You can not clock the PT to AES when driving a video deck.





.

[Fajita]

YEAH, what TV Post Sound said.


that's the only way to do laybacks. Lock to video reference.

[musikwerks]

Yes, that's what I meant... put much more succinctly by TVPost though.

[hummer]

I've definitely clocked off a deck during a layback before, no problems. In fact, that's exactly what I do if working in PAL (in an otherwise NTSC universe) ... However, if the deck is glitching, it's probably flubbing the digital audio output as well, which would screw up your reference. So, independent connections to a common reference is the safest way to go, provided that your house sync is PAL friendly.

Which brings up another thought... We only have one dbeta deck that can switch to PAL, and whenever I do it, I have to disconnect the house sync in order to get it to work, setting up a "closed system," which is the scenario in which I clock off the deck.

[Fajita]

we have 2 decks that are PAL and the rest are NTSC, we have PAL and NTSC black available, we usually have to reference the decks to each other and to PAL burst as well as send PAL burst to the SyncI/O.
Did I mention ours spans 2 floors, so it's a lot of up and down as well...

[TVPostSound]

We only have one dbeta deck that can switch to PAL, and whenever I do it, I have to disconnect the house sync in order to get it to work,

Of course, your house sync is NTSC!!

A separate PAL blackburst generator would be needed.

[Neil Whippey]

sadistically (more sadly though :/ ) - I find it slightly amusing hearing you guys having the same problems that I've had in the past when asked to do NTSC. At least PAL sounds like your friend

Seriously though, yeah that's got to be the answer, PAL black and burst feeding both the deck and the Sync box of your Pro Tools. Would be great to know what the final solution is!

Neil

[musikwerks]

If your house sync is NTSC then you absolutely need to disconnect all NTSC sync from your machines and tools rig. All PAL and nothing else. Our Avids are the same. When we have an NTSC project come through (which happens from Japan a lot) all PAL sync is disconnected and NTSC applied.

Also, make sure that your tools i/o is not receiving any audio coming from an NTSC clocked source. Not sure how it affects audio but it messes up sync if PAL video is stil routed to the inputs while working in an NTSC project.