Live Capture flickering/flashing

andielloyd

Hello Isadora friends!

Opening a show tonight (Jan 30th, Vancouver time!) that has a lot of live cooking and I am capturing the cooking using a Logitech Pro Webcam (1080p) above the stage! I am using FFGLPanSpinZoom in a background scene to frame different parts of the stage, not processing the image in any other way, and the live feed is up for some extended periods of time. Last night during dress rehearsal I noticed quite a bit of flashing/cutting out/flickering.

The webcam is run to the computer (2023 Macbook Pro, 64GB Memory, Apple M2 Max) via a 30ft USB extension. The computer is also outputting to four surfaces, so I imagine the processing needs are quite high.

Any insight on how I can lighten the load for the live capture so it behaves?

Any advice appreciated!

Woland

@andielloyd

A high load shouldn't cause flashing, cutouts, or flickering. That sounds like a connection or hardware issue. Is the extension plugged directly into the computer or is it going through a hub?

If you're outputting to four surfaces that are all the same mapping and content-wise, you could cut down on the processing power requirements by using a 1-to-4 signal splitter because then your computer will only need to output to a single display (the splitter) and the splitter would just send the same signal to all the displays. I realize that often the nuanced control afforded by having the option of sending different content to different displays and being able to map them individually is often integral to certain pieces, but anytime you're worried about the load on the show computer, (and can get away with it without compromising the piece artistically), the splitter trick is quite handy.

andielloyd

@woland

Thanks for the quick reply!

The webcam is connected via a USB-C adapter (screenshot below). It shares an input with an HDMI due to the amount of ports on the computer.

Unfortunately I do need control of all four surfaces (have two edge blended projectors and two channels running to televisions that show different images).

Sounds like when I get in I need to go secure the connections on the webcam in the air and at the computer!

Woland

@andielloyd said:

Sounds like when I get in I need to go secure the connections on the webcam in the air and at the computer!

Yes, I'd unplug and replug them, then inspect the long USB extension for damage.

The other thing to check is that the show computer is well-ventilated, as overheating can cause unexpected behavior sometimes.

Juriaan

@andielloyd

Hi this is likely an issue with the USB cable, 30ft is quite a distance for an usb and results vary greatly in the type of cable that you are using. Do you have any other cables? Are you extending the cable in any way? Is it a powered usb cable by any chance, since we can feed those power with an external source to make sure that our connection remains stable and usable.

Other thing that you could try is to make sure that the cable is strain relieved and that the cable is not near any other sources that are powered since they cause interference in the cable

andielloyd

@juriaan

It is a cable that has an option for a power boost but I don't have one. I'll ask the theatre. I also have access to USB over cat 6 extenders but I had found them to be less reliable in the rehearsal than the 30ft USB.

Juriaan

@andielloyd

Totally fine please check the adapter before plugging it in, you can permanently cause damage to your cable (and we don’t have that luxury now!)

What I mean is voltage, don’t put 12v thru it when it expecting 5v.

Oh and that multi port adapter is not doing any favors, it could be that you are sending too much signals thru that port / that the data transmission and receive are being capped, and especially web camera’s can have issues with that

DusX

@andielloyd said:

It is a cable that has an option for a power boost

Definitely try a power boost, and if that isn't available/working, try adding a small powered usb hub to the end of the 30ft cable and plug the camera into that (it will provide the power needed), that generally works.