I tried setting the exposure to manual using guvcview but I noticed that the value for absolute exposure keeps increasing although I had everything set to manual. (White balance and exposure) does it also occurs to you?
finaly i let automatic exposure, if i have time i will retry manual (did you change the exposure_auto_priority too?)
how would you guys rate the color accuracy of your settings by now? if via hdmi is, let's say, a 10, via camera it is a?
First i will note give 10 to hdmi grabber, color accuracy depend on grabber model, HDR / SDR transition are not well done.. with low cost grabber / spliter you can have micro short cuts too..
About color accuracy il would give a 7~8 on webcam, you have to considere ambiant light .
About quality of life i'm happier with the camera solution : no micro short cuts, or lots oh hdmi wire between grabber/spliiter . power supplys (i have a pi zero, one usb port ...).
The camera solution is not perfect but do the job