Venue Profile and video ref/Sync IO

[Robobo1]

Hello,

We use the Venue Profile as a broadcast console. We also multitrack to ProTools HD using the Profile.

This summer we are doing a live broadcast and multitrack recording and may possibly add video to the equation, necessitating Video Ref.

The setup would be standard:
- Video ref to SyncIO
- Word Clock out of SyncIO to FOH Rack
- DigiSerial cable to ProTools cards

Question is:
If the Video Ref signal drops, gets disconnected, cut, etc... what happens to the Venue console (which is running a live broadcast)? What happens when the Video Ref signal comes back? Are there any audible artifacts that will occur on the output of the console?

We will probably avoid using Time Code.

I'd assume that the ProTools recording stops when Video Ref drops and this may be ok. Anyone know? The broadcast is key though and we want to avoid any issues on the live output of the console.

Thanks!


Rob

[Sheldon Radford]

Hi Rob,

If the external word clock connection to the console drops out then there can be a momentary loss of audio as it switches to the internal clock. Same when switching from internal to external clock. I'd need to do some digging to figure out if the video ref is directly tied to the word clock out on the Sync I/O. If it is, then there is a chance that losing the video ref may cause an audio disruption.

Sheldon

[Robobo1]

Got it. I guess that this is more of a question re: the Sync I/O's capabilities then.

Would you mind finding that answer? We'd appreciate it!

[Sheldon Radford]

If a SYNC I/O loses video ref then its word clock out will also be affected, so this will cause an audio disruption. An alternative is to use a Rosendahl Nanosync, which will switch to its internal clock when video ref is lost, preserving the word clock output to the console.

Sheldon

[Robobo1]

Thank you for the reply, Sheldon. Very helpful!

[digidesigner]

Hi guys, please excuse my ignorance, but why is this type of sync needed from the video side, what it does in broadcast situation? I don't know much about broadcast but would like to know more and this sounds interesting. Seems strange to include something in the system that might disturb your sound when not understanding what is the benefit from having a sync signal coming from video especially when clock inside Venue is a good one and helps your stuff sound better.

[Robobo1]

Originally Posted by digidesigner

Hi guys, please excuse my ignorance, but why is this type of sync needed from the video side, what it does in broadcast situation? I don't know much about broadcast but would like to know more and this sounds interesting. Seems strange to include something in the system that might disturb your sound when not understanding what is the benefit from having a sync signal coming from video especially when clock inside Venue is a good one and helps your stuff sound better.

The video ref is not for the broadcast's benefit. It is so that the audio will be in sync with the video when the two are laid up in post. Without sync the audio would drift from the video... it's not noticeable in a short length of time, but after many many minutes it would be noticeable.

[Mystere1]

It's not technically kosher with digi but the best way I've found is to feed wc into the sync hd and FOH rack (among other things) from my big Ben.

I'm more worried about having wc drop during a show when pthd crashes than frame accurate sync. However, my syncing appears to be good to go.

My black burst is running directly into the sync and it uses that as the official reference.

I have two systems locked together and start record with ltc coming from my master LCS system.

[digidesigner]

Originally Posted by Robobo1

The video ref is not for the broadcast's benefit. It is so that the audio will be in sync with the video when the two are laid up in post. Without sync the audio would drift from the video... it's not noticeable in a short length of time, but after many many minutes it would be noticeable.

Hi, thanks, this makes sense. Sync is not needed for broadcast but for post, if the program is aired, but also is going to be taped and edited for later release it makes sense to have a valid sync from the start.