SYNC’ING TIMECODE THROUGH FIREWIRE
( DVX100B or HVX200 )
by Barry Green

One of the new features of the DVX100B (and also available on the HVX200) is the ability to sync timecode between multiple cameras, using the 1394 (“i.link” or “firewire”) cable.  This feature probably causes more confusion than any other.  In this article we’ll walk you through the process step-by-step, including pictures to show you exactly how to set up your camera to sync via 1394.

Why would you want to sync timecode?  Primarily when you’re shooting a multiple-camera event.  With timecode synchronized between the cameras it’s far easier for the editor to match up takes from multiple cameras and quickly and easily line up the footage so that the editor can freely cut between them.

First, it’s necessary to point out that a DVX100B can sync to any DV device’s timecode; it doesn’t have to be another DVX100B.  You can sync a DVX100B to a DVX100A, or an original DVX, or a DVC30, or a Sony PD170, or to a Canon XL2, or to any camera or deck’s DV signal.  And the same goes for the HVX200 – it can sync to another HVX200, or (when the HVX is in “DV” mode) to a DVX or any other DV device.  However, the HVX has to be set to the same recording mode as whatever you’re attempting to sync with.  That means if you’re trying to sync with an SPX900 when that SPX900 is in DVCPRO50/60i mode, you’d have to set your HVX to DVCPRO50/60i mode as well.  As long as it’s in the same recording format and frame rate, your camera can sync with 1394 timecode signals from other products.

Another point to keep in mind: the only type of timecode this works with is the timecode embedded in the 1394 cable’s signal.  There is no provision for TC IN/TC OUT jacks as found on larger broadcast cameras or on timecode-generating slates.  The DVX/HVX only work with 1394 timecode.

With that said, let’s walk through the steps necessary to set up your camera for 1394 timecode synchronizing.

The first thing to do is to make sure that your cameras are recording the same type of signal.  That means that all the cameras need to be recording either Drop Frame (DF) or Non Drop Frame (NDF) timecode.  Go through the RECORDING SETUP menu, to the TC MODE menu item, and ensure that they’re all set to the same mode.

(Note: if you’re shooting in 24P or 24PA, the TC MODE menu item will show up in blue and you can’t change it.  That’s because in 24P mode the timecode is always forced to NDF.  If your DVX or HVX is in 24P mode, you should make sure that all your cameras are in 24P, or at least in NDF mode).

Next, ensure that all cameras are using FREE RUN timecode.  You can’t sync using REC RUN time code; the very concept just doesn’t make sense.  You need freely-running timecode in order to sync.  In the same RECORDING SETUP menu, set the TCG menu item to FREE RUN.

Finally, if you’re working with tape (a DVX, or an HVX in tape mode) you’ll need to set one more item in the RECORDING SETUP menu.  Go to FIRST REC TC and make sure that’s set on PRESET.

At this point you designate one camera as the “sender”, and the other cameras as the “receivers”.  (Note: if you’re sync’ing to a camera other than a DVX100B or HVX, that other camera must be the “sender”.)  Plug a 1394 cable into the “sender” and into one of the “receivers”.  Leave the “sender” in camera mode, and put all the “receivers” into VCR mode.

(Note: if using an HVX in P2 mode, you put the HVX into “MCR” mode and you have to turn the thumbnails off, by pressing the AUDIO DUB/THUMBNAIL button on top of the camera!)

Now press the MENU button and go to the RECORDING SETUP menu on each “receiver” camera.  Choose the 1394 IN PRESET (or, on a DVX100B it’s called DV IN PRESET) menu item and set it to “ON”.

(Note: there’s a chance that the 1394 IN PRESET menu item might be unselectable/blue.  If that’s the case, go to the 1394 TC REGEN menu item and make sure it’s set to OFF.)

That’s it.  The cameras are now configured for synchronizing.  To synchronize the timecode, just press the RESET/TC SET button inside the LCD panel.

At this point both cameras will have their timecode exactly frame-accurate synchronized.  The 1394 cable connection is no longer necessary, you can disconnect it as it’s only used for that brief instant when you push the TC SET button.  And the cameras will stay in sync as long as you don’t turn one of them off, or change between CAMERA and VCR modes.  Sounds great, right?  Sure, but there’s a problem: you must immediately change the “receivers” to be in CAMERA mode, and when you do, you’ll lose a few frames of sync!

This is a frustrating reality of the timecode sync system: every time you toggle between CAMERA and VCR/MCR mode, the timecode will jump or skip a few frames.  And it’s unavoidable; since the “sender” must be in camera mode and the “receivers” must be in VCR mode, you have to toggle the receivers back to camera mode, and that means you’ll lose some frames of sync.  There’s no way to avoid it.  Using the 1394 sync method your timecode will always be a little bit off.

But, you can work around it and make the sync system still work for you.  The thing to do is to use the “receivers” to tape a few frames of the LCD panel (and timecode display) on the “sender.”  Point the “receiver” at the flip-out LCD on the “sender” and record a few seconds, like this:

By doing this, you have an exact reference to how far “off” the timecode is.  In this example the “sender” is at 2:50:10, and the “receiver” is at 2:50:17.  They’re off-sync by 7 frames; that 7-frame sync error was introduced when the “receiver” was switched from VCR mode back to CAMERA mode.  Now that it’s in camera mode no further sync error will be introduced, and they should stay exactly 7 frames out of sync for the rest of the day (unless someone toggles their camera back to VCR/MCR mode, which will cause another sync offset issue).

Another problem that can arise is caused by turning one of the cameras off.  That will also introduce sync offset errors.  Here’s an example of when one of the cameras was turned off and back on:

Turning the “sender” off and back on has resulted in it jumping significantly in timecode.  Surprisingly, they’re now only two frames off (whereas earlier the “sender” was 7 frames behind, now it’s 2 frames ahead).

Turning the cameras off and on repeatedly throughout a shoot, or toggling back and forth between CAMERA and VCR mode throughout a shoot, will introduce more sync offset every time you do it.  You have to turn the power off whenever you change a battery; any time you turn one of the cameras off and back on, you should probably consider re-sync’ing via the cable.  Re-sync’ing is very quick; once you’ve set all the menu items properly then re-sync’ing is a simple matter of connecting them via 1394 cable, putting the “receiver” in VCR mode, and pressing the TC SET button.  Again it won’t be perfect sync, but it’ll be very much “in the ballpark” so that your editor can line the footage up very closely right away, and then they can use the filmed shots of the “sender” timecode display to establish perfect sync.

The timecode sync feature isn’t perfect, but it gets us closer than other cameras in this price range offer.  Learn its idiosyncrasies and it can still be a valuable tool.