Avisynth+

[ajp_anton]

When going down in bit depth, dither=-1 means round, right? Or is it floor? Because I see a tendency of everything shifting ever so slightly "down".

If you do the following on a YV24 source (repeat a few times to magnify the effect)

convertbits(16)
converttorgb(matrix="rec709")
converttoyuv444(matrix="rec601")
convertbits(8)
convertbits(16)
converttorgb(matrix="rec601")
converttoyuv444(matrix="rec709")
convertbits(8)

, interleave it with the original, and histogram("levels"), you should see that on average, Y,U and V values are all going down. If dither=-1 rounds the values, shouldn't the average stay roughly the same?


edit:
dither_bits:
- Has no effect if dither=-1 (off).
- Must be an even number from 2 to bits, inclusive.
- In addition, must be >= (clip.BitsPerComponent-8).
I don't understand why any of these restrictions exist, except for maybe for implementation reasons. Not that I need this functionality, just wondering.