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Marcus Farrar May 14th, 2003 05:54 AM

Video Mixer question

I have a XL1s, Gl1 and want to know how can I use a my pro mixer with these cameras that do not have Genlock. I have a JVC KM-1200 video mixer that works great but the camera has to be genlocked to work with the mixer. This may be a simple question or imposible but I have never done it before and have no clue. I have an old digital tbc and a black burst generator. When I hook up my XL1s I can see the video but the picture will not lock in place. I am tring to use this mixer because I got it in perfect working order free.

Any answers greatly appreciated.

Jeff Donald May 14th, 2003 06:14 AM

These cameras can't be genlocked. They lack an external sync input. A simple frame synchronizer will work as mixer, or if the frame sync accepts external sync you could get your signal into the mixer that way.

Marcus Farrar May 14th, 2003 11:40 AM

OK, lets say I am not to bright. What is the diference in a Time Base Corector and a Frame synchronizer? If I had a frame synchronizer how would I hook it up?

I have been shooting and editing for years but this is my first time hooking up a video mixer with on gen-lock and I am lost.

Jeff Donald May 14th, 2003 01:31 PM

Time Base Error - Horizontal rate flutter of a video signal caused by tape stretch and mechanical imperfections in the tape transport system of a Video Tape Recorder (VTR)

Time Base Corrector (TBC) - Electronic device that corrects the timing irregularities that occur during VCR playback. Correction is not necessary between a VCR and TV for direct playback.

Frame Synchronizer - A digital buffer that, by storage and comparison of sync information to a reference, and timed release of video signals, can continuously adjust the signal for any timing errors.

Many modern TBC's contain Frame Synchronizers, as well as Proc Amps. A full frame TBC works by stripping the old sync off the signal and replacing it with sync created by the TBC (internal sync generator). If the TBC is supplied with house sync (Black Burst generator, color bars etc.) then the output video will be timed to other production devices in the studio. The signal can then be mixed via various DVE's etc.

A Frame Synchronizer matches and times two different signals. It could be the output of two cameras, camera and VCR, TBC and camera, etc. Many frame synchronizers will accept external sync (house sync etc.). The output of the frame synchronizer can be sent to mixers etc. for additional processing, effects etc.

Marcus Farrar May 14th, 2003 02:06 PM

Jeff knocks another one out the ballpark.

One more quick question. Would I need a Frame Synchronizer for each camera or would one work for all of them.

thanks again

Jeff Donald May 14th, 2003 02:26 PM

Some are single channel and adjust the source to the house sync. Some are multi channel and adjust the sources to each other or house sync if it is supplied. Some mixers contain frame syncs. Many of the modestly priced Panasonic mixers (MX10, MX12, MX30, MX50) contain frame syncs.

Marcus Farrar May 15th, 2003 06:04 AM

Do you think it would be worth it to get a Frame Synchronizer or should I just get one of the Panasonic mixers. If I got a used mixer I have seen them go on Ebay for about 400 to 700 and they have frame sync. If I keep the mixer I have I will need to get posibly a frame synchronizer for each camera. That could be very bulky for a field shoot.

Jeff Donald May 15th, 2003 06:48 AM

Marcus, tell me a little more about how you're going to be using the mixer and I can better advise you.

Marcus Farrar May 15th, 2003 09:59 AM

I do most of my editing on my computer with Final Cut Pro 3. In the past we just shoot with two cameras and edit the tapes together on the computer. Now we have this mixer we can mix the two camera shots on location which as you know will save a lot of time. Mostly we would use the mixer for instructional video. We would just use cuts between the two cameras (XL1s/Gl1).

I have gotten used to the pro mixers working in production for larger companies and like the way the pro mixers are set up. You can mount them in a case (rack mount) which is cool for transporting on location. Like I said I got this one free. If it is too much trouble to sync my cameras I may just sell it and get one the Panasonic ones.

So basically we just want to be able to cut between two cameras and at times a VTR for on location video shoots.

thanks again

Andre De Clercq May 15th, 2003 01:03 PM

Marcus I don't understand yr problem. As far as I can verify, your KM-1200 will do the job (resyncing...like all digital video mixers do)) with up to 4 independant (non locked) sources.
No extra genlock issues are involved unless you want to genlock to a thirth source.

Marcus Farrar May 16th, 2003 06:45 AM

Ok well maybe I am not hooking it up correctly. When I send the video from my XL1s or Gl1 the picture just keeps flipping on the program out. The picture will not settle or lock into place. You think I may be hooking it up wrong? I have the manual but it really dose not tell you how to hook up a cameras without genlock. If you have some advise on how to hook this up, please advise. What I have done is not working for me.

Are you telling me that I do not need a frame sync or TBC.

Jeff Donald May 16th, 2003 09:26 AM

Many (if not all) digital mixers incorporate a frame synchronizer. If your mixer has the ability to accept external sync, there is probably a switch for internal sync. If the switch is set to external sync and none is supplied, the picture will flip. Try locating the switch and setting it to internal sync.

Marcus Farrar May 16th, 2003 01:32 PM

OK, the manual says that input 5 can be used for external sync or if left open internal sync. I have tried just putting inputs in 1 and 2 with the internal sync but the picture still flips. It has to be gen-locked. I am almost sure of that now. My question is how do I hook up a video source using my TBC? I don't know where to plug in the cables from my mixer to the TBC.

thanks again

Jeff Donald May 16th, 2003 01:45 PM

Marcus, is this your KM 1200. If so I don't think it incorporates a frame sync and you can only use it with cameras that accept external sync (genlock).

The TBC's could accept sync from the mixer and then the cameras could be input into the TBC's. Then the output of the TBC's would go to the mixer. The TBC's could be used to match the cameras if they have a Proc amp built in.

So, for your set up you need either cameras that accept external sync, or a mixer that has a frame synchronizer, or a TBC for each camera that does not accept external sync (TBC's must accept external sync from the JVC mixer).

Andre De Clercq May 16th, 2003 03:38 PM

I don't see from the specs why this mixer would not resynchronize its sources and you would need genlocked cams or TBCs. I hope yr 75 ohm termination switches are set "on"...unless you apply feed-trhough to other 75 ohm equipments

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