imagemagick, Large 3x3

# draw 6x6 pixel tile that will be used for video-degradation effect
# similar as gimps large_3x3
convert -size 6x6 xc:black -fill red \
-draw 'point 0,0' -draw 'point 0,1' -draw 'point 1,0' -draw 'point 1,1' \
-fill green1 -draw 'point 2,0' -draw 'point 2,1' -draw 'point 3,0' -draw 'point 3,1' \
-fill blue -draw 'point 4,0' -draw 'point 4,1' -draw 'point 5,0' -draw 'point 5,1' \
-draw 'point 0,2' -draw 'point 1,2' -draw 'point 0,3' -draw 'point 1,3' \
-fill red -draw 'point 2,2' -draw 'point 3,2' -draw 'point 2,3' -draw 'point 3,3' \
-fill green1 -draw 'point 4,2' -draw 'point 5,2' -draw 'point 4,3' -draw 'point 5,3' \
-draw 'point 0,5' -draw 'point 1,5' -draw 'point 0,4' -draw 'point 1,4' \
-fill blue -draw 'point 2,5' -draw 'point 3,5' -draw 'point 2,4' -draw 'point 3,4' \
-fill red -draw 'point 4,5' -draw 'point 5,5' -draw 'point 4,4' -draw 'point 5,4' large3x3.png

 # tile small to big
convert -size 1920x1200 tile:large3x3.png large3x3_full.png

# does it blend?
convert noiseAndDirt-4227.png large3x3_full.png -compose blend -define compose:args=10 -composite woot.png

https://www.imagemagick.org/Usage/compose/#blend

# or better: watermark
convert noiseAndDirt-4227.png large3x3_full.png -compose modulate -define compose:args=4,100 -composite woot.png

# or without tiling the small tile first
convert noiseAndDirt-4227.png -size 1920x1200 tile:large3x3.png -compose modulate -define compose:args=4,100 -composite woot2.png

 convert -background none noise.png debian.svg -gravity center -compose over -composite out.png 
# -compose darken 
# -compose luminize
# convert -list compose