hi awawa and thanks for your work!
this works quite well for me. combined with adjustments to the v4lctl this produces a preview picture in hyperion which comes pretty close to the original on screen.
at least in well-lit scenes. when things go dark however the colors of my apa102 stripe have a strong green bias. even though the preview picture still looks fine.
so i suppose this has something to do with my setup/config as i am still struggling with USB capture in low light scenes in general (where the LEDs are either too bright and dont turn off at all or they start flickering when they're just at the threshhold of turning off)