Oh damn, sorry. I created so many functions to test things that I mixed up variable names and parsed non-greyscale frames to the Optical Flow bit.
So now that the script is working, it is giving me the same error as the other when it reaches dis.calc(...):
-DDIS_BORDER_SIZE=16 -DDIS_PATCH_SIZE=8 -DDIS_PATCH_STRIDE=4 -DCV_USE_SUBGROUPS=1 -D AMD_DEVICE
C:\Users\user\AppData\Local\Temp\comgr-7326e0\input\CompileSource:186:12: error: use of undeclared identifier 'sub_group_reduce_add'
186 | sum_diff = sub_group_reduce_add(sum_diff);
| ^
C:\Users\user\AppData\Local\Temp\comgr-7326e0\input\CompileSource:187:15: error: use of undeclared identifier 'sub_group_reduce_add'
187 | sum_diff_sq = sub_group_reduce_add(sum_diff_sq);
| ^
C:\Users\user\AppData\Local\Temp\comgr-7326e0\input\CompileSource:226:11: error: use of undeclared identifier 'get_sub_group_local_id'
226 | int sid = get_sub_group_local_id();
| ^
C:\Users\user\AppData\Local\Temp\comgr-7326e0\input\CompileSource:360:11: error: use of undeclared identifier 'get_sub_group_local_id'
360 | int sid = get_sub_group_local_id();
| ^
4 errors generated.
Error: Failed to compile source (from CL or HIP source to LLVM IR).
It still runs to the end, but it seems to not use much if any GPU resources (my rig consists of a Ryzen 5 7600 and a RX 7800 XT, fairly new and moderately powerful pieces of hardware).
Just to shine more light on my situation, I am learning this because I am trying to help a relative who got a freelance job in which one of the steps is checking large amounts of video evidence for forgeries, so compute time is unfortunately already important to me.