MobileRead Forums - View Single Post - Native or computer processed dithering for CBZ manga books?

NiLuJe · 02-21-2023, 01:42 PM

The algorithm used in KOReader on devices without hardware dithering (i.e., yours) is actually ImageMagick's 8x8 ordered dithering

.

It's pretty damn fine for this purpose; but Riemersma will look ever so subtly more natural (except it's been broken for years, so, use FloydSteinberg, which is almost as nice).

The main gain in going with preprocessing is the scaling process, though, not dithering; you'll get much nicer (and expensive) scaling with heavy-duty ImageMagick scalers.

(e.g., I use this script myself. Spoiler alert: it'll chomp on your CPU. A lot.).

02-21-2023, 01:42 PM	#2
NiLuJe BLAM! Posts: 13,506 Karma: 26047202 Join Date: Jun 2010 Location: Paris, France Device: Kindle 2i, 3g, 4, 5w, PW, PW2, PW5; Kobo H2O, Forma, Elipsa, Sage, C2E	The algorithm used in KOReader on devices without hardware dithering (i.e., yours) is actually ImageMagick's 8x8 ordered dithering . It's pretty damn fine for this purpose; but Riemersma will look ever so subtly more natural (except it's been broken for years, so, use FloydSteinberg, which is almost as nice). The main gain in going with preprocessing is the scaling process, though, not dithering; you'll get much nicer (and expensive) scaling with heavy-duty ImageMagick scalers. (e.g., I use this script myself. Spoiler alert: it'll chomp on your CPU. A lot.). Last edited by NiLuJe; 02-21-2023 at 07:45 PM.