Synchronous capture between two devices

[Brandt Wilson]

Do any of these tapeless solutions offer frame accurate jam synchronization between multiple devices from an external clock?

[Daniel Kohl]

I'm assuming that you are talking about something like a "lock-it" or a TC generating Nagra or DAT recorder / player.

None of the units I have looked at have an input for a TC signal. The FS-4 is the only one that seems to even offer a TC option. I think that the FS-4 Pro version has a TC set function, and may have TC free-run. I don't know how accurate it's TC is, as far as drift over long periods of time, though.

Are you looking for this function for playback or multi-camera purposes?

Cheers

[Brandt Wilson]

I'm looking to synchronize multiple cameras, preferably with field-level accuracy.

[Daniel Kohl]

This is just a suggestion that has nothing to do with how you are capturing or recording the video material. One used to be able to read TC recorded to one of the audio tracks when editing with an Avid. This may still be true. (I haven't worked with an Avid for a long time now). That might help you. You could record the signal from a central TC generator to one of the audio channels on each of the cameras. Or use "Lock-its".

And I'm sure that you are aware of the method of starting all cameras in a multi-cam shoot and letting them run, without stopping, for as long as they can. In this way making it only necessary to synchronize them during the edit, only once per tape.

This method is useless of course for very long events, or events where the cameras have to be turned on and off periodically.

Good luck

[Brandt Wilson]

I'm not familiar with Lock Its. What are they, and how are they used?

Thanks!

[David Priestley]

Midi over lan produce multi device sync solutions that are worth checking out

[John Colette]

A lockit is a timecode generator from Ambient - one of the coolest companies in the world IMO

www.ambient.de

they make timecode slates and surround boompoles and other great sound stuff

to get production sync - [on a SONY anyway] line up 3 or 4 cameras, using time of day timecode, and set them all using the IR remote. They will run time of day after being turned off, through tape changes etc....

They can all then be used "multicam" in FCP as different angles. The sync is pretty good.

Or - for $ - lockits on t/c inputs [like the XL-H1 has]. A friend edited a TV series using 8 digibetas sy6nced this way and FCP as the editor. Worked great!

-j

[Daniel Kohl]

Hey John,

Thanks for your response - I had completely lost track of this thread. And to be honest I didn't know who the maker of the Lockit was.

One additional comment: you can also output the Lockit to an audio channel on the camera. Avid used to (and probably still) has a function which makes acoustically recorded TC visible in the Avid time line. This would theoretically make it possible to TC couple cameras which do not have programable TC or a TC in.

[Sean McHenry]

Hey folks.

I have done some testing this last week with our FS4 units. Here is the WHY of what I did.

We noticed that the files no matter what format we captured in were splitting at the 2GB limit of 9+ minutes of capture, no matter what record mode we used. We also noticed the TC was dropping frames, not the video, but the TC over the breaks. An example was, the recorded footage was obviously contiguous from frame to frame across the break, that is, no missing video frames. The frame before the break was 00;11;26;00. The frame imediatly after the break was 00;11;26;06. Somewhere the TC dropped or added 6 frames. The video was correct but the TC was obviously wrong.

We noticed in several other 9+ minute breaks that the TC seemed to be correct across those breaks. HOWEVER, after examining the tapes that we shot simul on the camera while going to the FS4 units, we noticed the tape TC and the FS4 TC are constantly 2 or 3 frames off. Frankly, I trust the tape to have the right TC. This means for us, a large post house, this method is not functional for projects we may have to revisit later as re-digitizing old projects will be off several, and up to 6, frames off. In a long form project, that's a hard thing to deal with. If we had to manually nudge every one of hundreds of clips to the right spot in a project we had already done once, that's a whopping extra expense.

These are my experiences with the FS4. YMMV.

Sean



Looking into this further I decided to