Syncing Multiple HD Rigs Question

[antonis]

Hey all,

I just need a bit of clarification if possible please. I've got a HD3 and HD2 system running with Pro Tools 8 HD and currently linked with Video Satellite LE. The HD2 system is the Video Satellite, outputting video using a Blackmagic Intensity Pro.

I want to upgrade my studio's sync features and lock to tri-level. I am getting an AJA GEN10 to provide sync and a Decklink Studio card to replace the HD2 rig's Intensity Pro. Also, I've purchased a Sync HD, which I am thinking to connect to the HD2 system and both the Sync HD and the Decklink Studio will be receiving Tri-level from the GEN10.

I just purchased a Sync I/O as well (I could not afford a second Sync HD) which I am thinking of connecting to the HD3 system and send SD Black and Burst from the GEN10 (AJA's GEN10 seems to be able to output both signals). Hence, up to this point all systems should be sync'ed to the video ref sync.

Does this wiring seem to be right? Is there something I am not taking under consideration with this one?

[Craig F]

That should all be fine, Word Clock from the Gen10 (if it has it) would be the other option if SD Black is problematic

[antonis]

Hey Craig. Unfortunately no word clock from Gen10. How come you mention potential problems with SD Black? Is that a common problem?

[Craig F]

not that I've encounter but you never know when one session is not going to play nice

[Postman]

There are two potential flaws in your plan, I'm sorry to tell you.

The biggest one is with Gen10. It does not behave exactly as you might expect. Although it has simultaneous SD (bi-level) and HD (tri-level) outputs, the outputs come from two different generator circuits with a common master clock. A common clock means they do not drift apart, but the two generators do not align their frame edges to each other. Even when they are both set for the same frame rate (such as 25fps), each time you power up Gen10 or change Gen10 settings, the alignment between the two generators takes a random relationship, up to 1/2 video frame apart.

The other potential flaw, even if the above was not true, is when working at 23.976 or 24fps. You only get 29.97fps from Gen10's SD outputs when generating 23.976 or 24fps tri-level sync. So, you won't get frame edge aligned audio from your two Pro Tools rigs because the frame edges between the two reference outputs may have no predictable relationship to begin with.

You could send LTC from HD2/SyncHD rig and lock up the HD3/SyncIO rig exclusively to that, or for slightly quicker lockups use LTC for positional reference and word clock (from SyncHD) for speed reference. I don't really know how well that works as a satellite, but doing so does give excellent sync performance when chasing timecode... with slower lockup times than satellites are otherwise capable of.

If 23.976/24 is NOT part of your workflow, and you primarily work with 25/50 and/or 29.97/59.94, you have another option. I am thinking Decklink Studio can give you a simultaneous downconvert while playing HD. Use that downconverted output as a reference for SyncIO/HD3, instead of Gen10. In this scenario Gen10 provides tri-level to the HD2/Decklink system (which firmly locks Decklink and Pro Tools), meanwhile Decklink outputs a frame-edge locked down-converted output (I hope it is frame-edge locked!! Does anyone know for certain?) that SyncIO can lock onto. That should give near-perfect sync. All bets are off with 23.976 though.

Are you sure you cannot afford another SyncHD? That is the best choice to work within your existing setup, if you can swing it.

[MIKEROPHONICS]

I think it is ok to use the composite output from the decklink as Postman wisely suggested - I send mine back into the Sync HD to generate BITC and it seems to be stable locking PT to it when the decklink is fed with Tri.

Your other option is get an ESE dv 319 (instead of the AJA Gen10) which outputs SD and HD syncs that are frame aligned (it is what I have for this very reason - and the fact that the dip switches are on the front of the unit and it is rack mountable too).

[antonis]

Hey all,

Many thanks for the replies back. Much appreciated!

The ESE DV-319 it is then. I did not know it existed (and just found the previous thread that you were asking almost the same thing Mike).

Were did you get yours from Mike?

One more question if that's alright:

I might try to get as many 192 Digitals I can afford to make the HD2 an aux box and the stems printing machine. Once I video reference the Sync HD with Tri-level and the Sync I/O with black and burst, I will Loop Sync the connected I/O units with their respective Sync boxes.

I wouldn't need to further consider word clocking connections, would I?

[MIKEROPHONICS]

Provided all is clocked to same video then nope.

My ESE came from Paul at Fumeo video +44 (0)115 846 0022

[Postman]

So what is your plan with 24 fps material?

[antonis]

I will be going with the ESE DV-319 suggestion, since it seems this will do what needs doing.

Unless of course other suggestions are out there. But the 319 seems fine for a slightly higher price tag.

Many thanks for shedding light on the Gen10 let down feature Postman. I would have otherwise bought the little unit, figuring out mid-project what it cannot do!