Multi-Camera Won't Stay in Sync

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dvxnerd

Active member
So, we tried a multi-camera shoot. We origannly were going to shoot in 720/24pN, but following Barry's directions, the cameras would drift out of sync. We first switched to 720/24p to sync the cams and then switched to 720/24pN.

We decided that perhaps the 720pN would just not work, and we didn't want to take a chance. We decided to shoot DVCPro50 480i/24pA. They seemed to be in sync, but we found out later that they drifted again. This is incredibly disappointing.

Here's what we did:

Put both cameras in free run/tc preset mode. On one of 'em (designated the "recipient", go to MCR mode and turn off the thumbnail screen, then go in the menus and turn on 1394 TC IN (or 1394 TC PRESET or something like that). Connect 'em via firewire. On the recipient, press the TC SET button inside the LCD panel. It should read the incoming firewire stream and force its tc preset to match.

Swap back to camera mode, and it should have identical timecode to the other unit. Then set both of 'em back to 720/24pN mode, and you should be good to go.​

As I said before, we started off in 720, but decided to go 480i/24p. This really seemed to work at first, but it didn't work, and now it's going to be a pain to edit. :(
 
Hi:

Still awaiting an answer on this from Panasonic in Japan (why not go directly to the source?)

Will let you know what I hear.

Dan
 
Did you at any point turn one of the cameras off (to change a battery, etc?) If so it's possible they could have gotten out of sync at that point and you'd need to re-set the TC...
 
Well, I took footage from early in the shoot when no batteries were changed, it had already drifted. Oddly enough, Mike (from New York City Final Cut Pro Users Group) is who synced it, and it was done right. It started perfectly.

There was one thing that I noticed that was a bit odd. Mike's camera had detail coring (or something coring) at 0. Mine was at -2 (from the factory). Every time he set his to -2, it would somehow go back to 0 after we were done with the sync process.

Adam
 
Are you shooting DF or NDF? If one of the cameras is in the wrong mode the TC will drift on that camera. Check each of your cameras footage info.
 
Did you change camera modes from 720 to 480 after syncing time code? Or from 720P to 720PN & back or really any mode change?
That would seem a very dangerous idea to me.

Also, how far did they drift over how long a period of time? Even pro cameras will often slowly drift apart, sometimes more sometimes less.. That's why if you want ironclad sync you need to keep them gen-locked.
 
Was working on this job with DVXnerd Saturday, the following is a more concise recipe we executed. I'd like to figure this out, or fix the recipe for future jedi generations of arm wrestlin' HD shooters.

Objective: shoot multiple HVX200's with common timecode in 720 pN mode.

1. power up both cameras, Set both cameras to 720 24p
RECORDING SETUP>Rec Format>720 24 p

2. Put both cameras in free run/tc preset mode
RECORDING SETUP> TCG> Free Run

On one of 'em (designated the "slave"), this camera will be set to accept the 'Master" camera freerun timecode

On Slave camera,

3. go to MCR mode and turn off the thumbnail screen,

4. Connect cameras via firewire (need 4 pin to 4 pin cable)

5. then go in the menus and turn on 1394 IN PRESET
MCR MODE Recording Setup>1394 TC Regen> OFF
MCR MODE Recording Setup>TC MODE> DF
MCR MODE Recording Setup>1394 UB Regen> ON
MCR MODE Recording Setup>1394 In Preset> ON

6. On the slave, press the TC SET button inside the LCD panel. It should read the incoming firewire stream and force its tc preset to match.

note: the camera counters TC displays matched up after several presses of the Counter Button, fyi.

7. Swap back to camera mode, and it should have identical timecode to the other unit.

8. Disconnect firewire

note: powering down camera seemed to help the process, but couldn't replicate on site.

9. Then set both of 'em back to 720/24pN mode, and you should be good to go.

note: Cameras did have sync TC displayed for several minutes, even after powering down and pulling the battery, and the TC display at the end of the event remained in sync, but the media files are over 7 seconds off at one point (don't know at this time if they drifted or or are consistent.)

thnx,
 
Is this really an issue? I mean after syncing the clocks are going to get out of sync over time, unless you're jamming it right?
 
Wait a sec. Checking P. 107 in the manual, it states, "The non-drop frame mode will be used when you set recording frame rate of recording format to 24P, 24PA or 24PN."

So, is this why they drifted?
 
Step number 9 says you switch modes to PN, I think the switching of modes is what got them out of sync.

Maybe try shooting time of day time code, or using the other camera as the master, and don't change modes.
 
In effect, that's what we were attempting, jam syncing one camera's internal clock (TGC) (slave) to another (master) via firewire. We still haven't a definitive answer on this procedure.
 
One backup plan that was suggested was to shoot the screen of the master camera with TCG visible with the slaved cameras. This presumes that the screen has no lag and the cameras TCG 's won't drift appreciably.
 
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