Strange video issues with 2 cameras (Green flashes and momentary pauses)

I have been testing a composition with two different SDI cameras through 2 Blackmagic UltraStudio Mini Recorders and running into an odd issue. Each camera is being displayed in a separate window. Both cameras use different frame rates. Camera 1 is a PTZ - 1080/29.97p and Camera 2 is a Fixed - 1080/30p. I keep getting a frame and a half green flash every few seconds on Camera 1 and slight pauses in video frame rate on Camera 2. I can understand this happening if I was trying to merge the 2 images somehow but they are each running separately in their own windows and only related by being in the same composition. Just to trouble shoot a bit I ran a second test with two Fixed - 1080/30p cameras and it appears to run smoothly with no pauses or green flashes that I could see, so it doesn’t appear to be a bandwidth or computer performance issue that I’m seeing. This clearly seems to be related to the mismatched frame rates even when running in separate windows. Any ideas on wether this is resolvable or not? I would hate to have to find a PTZ - 1080/30p camera when I have this nice one available right now for this project.

Do they need to be in the same comp?
Have you tried running two comps at the same time?
Are they outputting to the same screen or separate? i.e both trying to keep in sync with a 60hz referesh rate.

This was just a test but, yes, it will need to run in the same comp. The 1st camera is going to be an actual video feed of the event and Camera 2 is for reading barcodes, they are running in separate windows but the barcode reader camera provides text information to overlay on the video feed camera.

running two comps at the same time as a test might help rule out any conflict with the drivers or hardware.
the green flash sounds like it could be from the camera or input device to me.

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Yeah, I’d recommend seeing what happens if you split it into two compositions. Also, is there some other Blackmagic capture app in which you could test receiving both streams simultaneously?

When the problem happens, do you see any messages from Vuo in Console?

OK, I was finally able to get 2 of each camera back for testing. Here are my findings:

Composition Description Camera 1 Camera 2 Results
Both cameras in same composition but separate Windows PTZ 1080i/59.94 1080p/30 Periodic Green Flashes (once ever 10-20sec)
Both cameras in same composition but separate windows PTZ 1080p/29.97 1080p/30 Periodic Green Flashes (once ever 10-20sec)
Both cameras in same composition but separate windows PTZ 1080p/29.97 PTZ 1080p/29.97 No Flashes
Both cameras in same composition but separate windows 1080p/30 1080p/30 No Flashes
Each camera running simultaneously in separate compositions PTZ 1080i/29.97 1080p/30 No Flashes

Any ideas why this is happening? One camera will be used for reading barcodes (intended to replace the webcam I’m currently using, SDI is safer choice over a webcam with USB extender) for generating the overlay graphics and the PTZ will be replacing an old HDMI camera as a live camera. Both must be running in the same composition.

Signal drift, try adjusting the overscan to wrangle it in place for some time (it will still drift after some time though). Most likely something in the chain thinks you’re running everything at 30fps when you run it at 29.97 (or the other mismatches). Over the 10 - 20 seconds that .03 leftover adds onto itself, and the box/driver/something don’t know what to do when it gets info from the middle of the frame where it expects the beginning, and probably tries to auto adjust to the signal. You shouldn’t run them at different framerates though, and it is far from reccommended. Putting a decent scaler in between can also solve this issue.

Can you check if the 30fps camera has a NTSC mode? Or if the PTZ can be run in PAL mode? Which camera models is it? If they both have 24/25fps modes that might also solve it.

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+1 to @MartinusMagneson’s suggestion. If you can test in some other Blackmagic capture app besides Vuo, even better. That would eliminate one variable.

If for some reason you can’t get both cameras working in the same composition, another option would be to have one composition receive from the barcode camera, decode the barcode, and send it to a second composition (via OSC, or by writing text to a file).

If I were mixing the two video signals it would make sense that the drop frame and non-drop frame rates would conflict and cause this issue, however I am not. They are in the same composition yes, but both are in separate windows and should be handling the frame rates independently, right??? I’ve attached a completely stripped down version of the project to eliminate all other possible causes for this issue.

Unfortunately the neither camera can be switched to match the other cameras frame rate.

  • Live Stream Camera: Sony EVI-HD1 PTZ camera
  • Barcode camera: Crazyfire HD HZ-100P/SDI camera

Camera Test.vuo (2.92 KB)

Ok I’ll have another stab at this.

Render Image to Window uses the refresh rate of the monitor you are rendering to. ( I think).
The Blackmagic inputs work at whatever framerate you have coming in from the camera.
As your cameras are different framerates there is a conflict. ( I’m pretty damn sure that’s where the issue begins).

Are you rendering both windows to the same monitor? Have you tried it with two monitors?

Can you tell the windows how often to render with Fire Periodically, and make those framerates match both the cameras and the monitors refresh rates?

Maybe add a Hold Value with a Fire Periodically on the input so that you are telling it to drop frames on the higher FPS camera? Maybe take them both down to 25fps…

Do you use Resolume? I believe you could easily set up both inputs as sources in the demo version to see if it works in that software.

but both are in separate windows and should be handling the frame rates independently, right???

Maaaaaybe? I’m not too sure about it to say the least. Have you had open the Desktop Video setup window while looking at the issue? It might be that the driver wants to lock down everything to the same framerate. Using their mixers locks everything in the chain to the same framerate, but I don’t know if this is transferrable to the desktop video products (I’d assume so since it is the same driver). 30 and 29.97 might be so close that you get partial delivery anyways, but then drops out when out of sync.

Looking at the camera specs, it seems that you should be able to switch both to 1080p 25fps. Can you try that and see if you have the same issue?