Long AV1 encodes setup

Commands (run in an MSYS2 shell):
ffmpeg -i presage.mkv  -filter:v "select='gt(scene,0.5)',showinfo" -f null - 2> PresageSC.txt
grep showinfo PresageSC.txt | grep -o "pts:[\ 0-9.]*" | grep -o "[0-9.]*" > pts.txt

Python scripts:
select.py, to select timestamps at least 150 seconds apart:
---
filePTS = open('pts.txt', 'r')
PTSArray = []
for line in filePTS:
	PTSArray.append(float(line)/1000)
filePTS.close()

startPTS = 0
for PTS in PTSArray:
	if (PTS - startPTS) >= 150:
		print PTS
		startPTS = PTS
---

gencmd.py, to generate the ffmpeg cmdline to split the video:
---
filePTS = open('selectedPTS.txt', 'r')
PTSArray = [0.000]
for pts in filePTS:
	PTSArray.append(float(pts))
filePTS.close()

PTSIndex = 1
while PTSIndex < len(PTSArray):
	print 'ffmpeg -ss %0.3f -to %0.3f -i presage.mkv %d.y4m' % (PTSArray[PTSIndex-1], PTSArray[PTSIndex], PTSIndex)
	PTSIndex += 1

print 'ffmpeg -ss %0.3f -i presage.mkv %d.y4m' % (PTSArray[PTSIndex-1], PTSIndex)
---