g-force said:

One quick suggestion, could someone replace the last line of the restore stars stage with:

MT_Merge(prest,source,last,chroma="copy first")

and let me know what happens?

thanks!

-G

yes, omitting the MT_Logic.. part from the restore stars stage does eliminate the artifacts.

as you probably already suspects the problem seems to come from MDegrain1 in this line:

pcorr = source.MDegrain1(idx2,bw_vec1,fw_vec1,thSAD=800,thSCD1=150,thSCD2=75,plane=0)

pcorr has a lot of artifacts high motion frames and looks like this: