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In camera flicker when recording projected video screen


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I am working on a project that is being recorded with a projection screen in the background. When the camera sees the screen there is flicker in the image. This, I believe it due to a miss match in frame rate of the camera and the image refresh rate of the projector. However, when looking through the accepted input signal of the projector it seems to only accept video signals in 50Hz or 60Hz, unless the input is SDI. Also, when I look at the graphics card resolution options only 60Hz is an options for the refresh rate. Does this mean that this projector will only refresh at 60Hz? Thus, we need to adjust the camera shutter, either at 30fps or 60fps?

Any advise or thoughts are appreciated. 

projector model: Panasonic RZ970

Thank you!

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You are correct, most likely your camera is at 60 fps and it is not in synch with the WATCHOUT Display output. Reducing your cameras rate to 30 fps is a potential solution. If you must record at 60fps, a WATCHPAX 60B or 60C contains a hardware synch card (or any server with a hardware synch card) that can be genlocked to house reference which would also require you to genlock the camera as well.

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BTW reducing the WATCHOUT Display / projector refresh rate would likely make it worse. Either run the camera at a slower refresh rate or lock the server and camera to a common reference.

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Thanks fjk, 

If I am understanding correctly, my options are adjust the frame rate in camera to help eliminate the flicker or put a synch card in the WO server and synch both to a common reference.

The camera's current frame rate is 23.98 and after some research that is not a supported refresh rate of the Panasonic projectors, thus I do not think they system will adjust to their camera settings.

 

 

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I would try to adjust the shutter time. Most projectors run on 50 or 60fps. You might be able to force the graphic card to a lower resolution like 23.98 but this would probably require a programmable EDID manager behind the graphic card output or even better an active scan converter.

Page 202 of the RZ970 manual states that the projector supports 23.98 at 2.048x1.080 and on page 200 I see 1.080/24p for the other inputs.

A graphic card will only output such frequencies if the monitor's EDID states that the monitor can take it.

 

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Thank you for your help. 

It is true that the projector will support those refresh rates but it is only over SDI and we are cuttingly running HDMI. However, this is a possible solution. Currently the DP has adjusted their shutter speed to accommodate the 60fps of the projector. 

I attempted to force a custom EDID from the graphics card however that did not work. Possibly because, as you state, I would need a EDID manager or Scan converter between the graphics card and projector. 

 

Thank you for your help. 

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