Q's - HVX200 and motion control rig

Joe Shaw

Joe Shaw

Well-known member
Thought you might be interested in this and may also be able to help out with a question.

I've hooked up with some genius guys who have invented a very compact motion control system. I wanted to get them to try out the HVX200 with it to see how we could make it compatible. Today we had a chance to marry the two up and we shot a quick DV test which I can post later on.

My main question is this - they are wondering if the HVX puts out or is capable of putting out a 'pulse' through the video signal that they can lock onto. They are used to mainly using film cameras with the occasional digibeta and their system relies on the 'pulse' that these cameras put out to lock/sync with their system. My understanding is that the camera pulses every frame and that with this information they can cope with different frame rates etc.

Perhaps there is someone out there who knows what I'm talking about and can enlighten us all...?!

The pictures are of the HVX on a tripod with the motion control head, a stupidly large scope being used to look for elusive pulse and the control/monitor - a pocket pc powered system with remote wheels.

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I don't know if the HVX is capable of outputting the signal they're expecting or hoping for. However I understand the importance.

What they want is not just to mimic the same movements, but to have the camera at a precise location for every frame of the shot, time after time. in the final composited shot, the compositing artists will have to combine each frame precisely for masking, background and beauty passes, and all of them will have to register throughout each take.

That means that on frame 36 the camera has to be at position XYZ within certain precise tolerances or else the composite won't work at all. And it'll be too painful to try to adjust each frame of each take to get every element to match throughout the composite.

I'd thoroughly enjoy being the guy who comes up with the technical solution to that one!
 
That is exactly it. And it works flawlessly with their system and the film cameras they have been using. It's incredible to watch.

They have used digibeta too though.. which seemed capable of sending this frame information within its video signal...

Anyone else wanna chime in?
 
appreciate the input, but no, that's not it. They are definitely looking to find out if the HVX outputs a pulse in the video signal they can sync with...
 
Sounds like you are talking about a Black Burst generator, taking the composite signal from a device (HVX) to a BBG box. Often sync is fed through a whole facility, so all devices are locked in sync. I am not sure if this applies to the HVX.
 
overlandfilms said:
Jshaw,

Was that video the HVX? Kinda small, but the sample looks very, very good.

e
Click to expand...

Yeah that was the HVX - shooting DV too!

Next step will be to shoot some DVCPRO 50 with some greenscreen. If we can find the answer to this sync pulse thing we could play around with the frame rates as well.
 
It sounds like they are talking about VITC (pronounced vit see) or Vertical interval timecode. It is a timecode that is embedded within the video signal, typically in the vertical blanking interval. You should ask these guys what output from the digibeta they were using to get the pulse. They may have been using the Genlock out signal or if they were using a video out signal they would have some sort of box that would read the VITC. If that's the case you should be able to take the composite signal out of the HVX and extract the VITC from that.
 
Many thanks for the reply. You know, it may even be the blanking interval they are looking for... Do you think that changing the frame rate on the camera would have any effect on this? Because we hooked the camera up to a scope and saw no change as we cycled throug them.
 
Bi Phase/Tack Pulse

A very basic timing reference that contains NO positional reference, just square waves (pulses). NO, the HVX will not send this type of sync. The Pro Tools SYNC I/O can interpret VITC or LTC and send out the Bi Phase PULSE.
 
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