New in this version: DynamicHires picture quality improvements, bug fixes and additional dithering modes, experimental MSX2+ YJK conversion.

Download:
Main mirror (all stable and testing versions)
External mirror

Changelog:

• Fixed dynamichires accurate mode crash bug.
• Fixed checks dithering glitch (Amiga indexed modes).
• Fixed iff saving bug.
• Improved dynamichires non-interlaced image quality.
• Amiga indexed modes and dynamic hires: added bayer 2×2, bayer 4×4 and bayer 8×8 dithering (arbitrary-palette version, experimental). Enabling CIEDE makes bayer 8×8 quite slow. Bayer 4×4 and 8×8 supports strength regulation (5-95%, 100%=use recommended value).
• Custom mode: added bayer 8×8 dithering.
• Experimental MSX2+ screen 12 conversion (19268-color YJK mode). I wanted to implement this mode to compare it against HAM6 as it’s another lossy compression implemented in hardware. Picture quality seems to be better than non-dithered HAM6 due to higher color depth (15-bit vs. 12-bit) and the to use of YUV-like colorspace for compression instead of pure RGB (four consecutive pixels in fixed-positioned blocks share J and K value, but each have different Y value).

HAM6 vs. YJK (using 1.5.1 beta):

Original image.

HAM6

YJK

HAM6 (zoomed)

YJK (zoomed)