LE 11.x now uses a GBM/V4L2 video pipeline which does not support the methods previously used to grab frames, and reimplementing that is technically non-trivial and probably won't happen. The best (only?) approach available now is to use an external HDMI grabber, so there is no 'software' dependency on acquiring frames to drive the LED's.
Will this be the same on Raspberry Pi5 ??