First pass - separate to keyframes

#This is a first pass script, you don't need to encode it, just run it once from the beginning to the end via player or VDub. Don't seek while it is running.
#It will dump all frames that are different into a folder along with timecodes file that will list all frames that are repeats of those dumped.
ffmpegsource2("C:\Users\Seedmanc\Desktop\vector.mp4")           # your source unprocessed video here
ConvertToY8( ).coloryuv(autogain=true,opt="") .converttorgb24   # autocontrast since images looked rather dim for some reason

global dir="c:\users\seedmanc\desktop\"                         # path to store images and logfile
global filename="file.txt"                                      # name of logfile

function write(clip c, int s, int d){
  global o= string(s)
  global p=" "
  global r=string(s-d)
  writefile(c,dir+filename,"o","p","r",flush=false)
}

imagewriter(dir+"%d.png",start=0,end=-1,type="png").trim(0,-1)+trim(1,0)
  # writing 0th frame and number, since it is not considered a scene change, but we still need it
writefilestart(last,dir+filename,""""TYPE int"""")
writefilestart(last,dir+filename,""""DEFAULT 0"""",append=true)  # header of the logfile

global ext="png"
global wildcard="%d."+ext
global counter=-1

ScriptClip("""a=current_frame"""+chr(13)+ \
 """(ConvertToY8.YDifferenceFromPrevious>10)? \
  ScriptClip(" counter=0 \
    write(last,a,counter) \
    imagewriter(dir+wildcard,start=current_frame,end=-1 ,info=false,type=ext)" ): \
  ScriptClip("counter=counter+1 write(last, a,counter)") """)

# Basically, what I do here is detect scenechange (by looking at difference between previous frame and current and when it is above threshold of 10 I write current frame and save it's number so that it will be used later as reference.
# If there's no change, then I don't write image, and don't change reference frame number.