@josey_wells
I was just documenting a bug report for YV12 chroma corruption in 1.9.6.2 when using a filtered clip in mvanalyse but you may already fixed it in 1.9.6.6 (at least for a blksize of 8).
However 1.9.6.5 and 1.9.6.6 both immediately crash for me with a blksize of 16 in the same code section as @mikeytown2 above. This for both YV12 and YUY2.
On a Q6600 with 1.9.6.6 and mvdegrain3 with a blksize of 8 on my test script I am seeing 10 to 11 fps with the multi versions compared to 1.9.5.7 at 2 to 3 fps.
Thank you for your work on threading this.