Dither

Bit-depth conversion with dithering — a port of fmtconv's fmtc.bitdepth plus the depth-dither modes from zimg (the engine behind resize.Point).

Converts a clip to another bit depth and/or sample type, applying a chosen dither pattern when reducing precision.

Usage

vszip.Dither(vnode clip, int bitdepth[, int dither_type=2, int sample_type, bint fulls, bint fulld])

Parameters

• clip:
  Clip to process. 8-16 bit integer or 16/32-bit float, any planar/gray color family.

• bitdepth:
  Target bit depth. Integer output: 8-16. Float output: 16 or 32.

• sample_type: (Default: 1 (float) when bitdepth == 32, else 0 (integer))
  Output sample type: 0 = integer, 1 = float. A float output is only valid with bitdepth 16 or 32.

• dither_type: (Default: 2)
  Dither pattern:

  #	Mode	Source
  0	Round (no dither)	zimg/fmtc
  1	Ordered (Bayer)	zimg
  2	Random (blue noise)	zimg
  3	Error diffusion (Floyd-Steinberg)	zimg
  4	Ordered (Bayer)	fmtc
  5	FilterLite error diffusion	fmtc
  6	Stucki error diffusion	fmtc
  7	Atkinson error diffusion	fmtc
  8	Floyd-Steinberg error diffusion	fmtc
  9	Ostromoukhov error diffusion	fmtc
  10	Void-and-cluster	fmtc
  11	Quasirandom	fmtc

• fulls: (Default: True for RGB, else False)
  Treat the source as full range. When neither fulls nor fulld is set the source's range prop passes through unchanged.

• fulld: (Default: same as fulls)
  Produce full-range output. If either fulls or fulld is given explicitly, the output's _ColorRange prop is stamped accordingly; otherwise the source prop is kept.

Notes

• An identity conversion (same depth, sample type and range) is a pure passthrough for every mode — following zimg, dithering to the same depth only adds noise, so it is skipped.
• Upconverting between limited-range integer depths is a pure bit-shift (no dither); dithering only kicks in when precision is actually reduced.

Examples

out = core.vszip.Dither(src, bitdepth=8)                       # 16 -> 8 bit, zimg random / blue noise (default)
out = core.vszip.Dither(src, bitdepth=8, dither_type=3)        # zimg error diffusion
out = core.vszip.Dither(src, bitdepth=10, dither_type=8)       # fmtc Floyd-Steinberg to 10 bit
out = core.vszip.Dither(src, bitdepth=32)                      # convert to 32-bit float
out = core.vszip.Dither(src, bitdepth=8, fulls=1, fulld=0)     # full -> limited range conversion