I’m still curious on which sources have extra frames (per your notes, since your final releases have them removed for GOUT-Sync), but am pretty happy with a script I found on Doom 9 for the process of detecting your inserted black frames.

#Specify the name and location of the output file
filename = “e:\output_black_frames_rotjswe.txt”

#Specify the threshold that will be considered black (0 = pure black)
global blankthreshold=16.1 #24 seems to be a reasonable number for black frames sourced from analog

AVISource(“D:\ROTJ\rotj.avi”).killaudio()

#Only look at half the fields (speeds up processing, though if you remove selectodd, it should help locate
#any half frames)
i=separatefields.selectodd.ConvertToYV12()

#Write the frame number
WriteFileIf(last, filename, “(AverageLuma(i)<blankthreshold)”, “current_frame”, append = false)