Dropping the res seems to have helped. THANK YOU!!!
Are we talking about the frame size decimation? Or the usb grabber resolution. I haven't messed with the grabber resolution. Those settings sound like the same thing to me so I don't understand. I had a lot of flickering issues at decimation 8, due to poor quality video and noise in the image. I couldn't go lower due to the Pi Zero using 100% cpu. I migrated to a Pi 3 which allowed me to use no frame decimation, which corrected the flickering, but there's a small, maybe 50ms delay. How long is your delay? I suppose it's personal preference on what is acceptable, but my delay is just barely enough to be distracting to other viewers. Note: when troubleshooting I do have smoothing turned off.