ConvertBits

[edit] ConvertBits

Changes bit depth while keeping color format the same, if possible.
If the conversion is not possible – for example, converting RGB32 to 14bit – an error is raised.

ConvertBits(clip, int bits [, bool truerange, int dither, int dither_bits, bool fulls, bool fulld ] )

(older bit-depth conversion filters – deprecated)

ConvertToFloat(clip, int bits [, bool truerange, int dither, int dither_bits, bool fulls, bool fulld ] )
ConvertTo16bit(clip, int bits [, bool truerange, int dither, int dither_bits, bool fulls, bool fulld ] )
ConvertTo8bit(clip, int bits [, bool truerange, int dither, int dither_bits, bool fulls, bool fulld ] )

clip   = (required)

Source clip.

int  bits = (actual bit depth)

Bit depth of output clip. If provided valid values are: 8, 10, 12, 14, 16 (integer) or 32 (floating point).

From 3.7.1 parameter is optional since no bitdepth change is needed when doing only range conversion (fulls-fulld) or artistic dithering (dither_bits<bit depth)

<3.7.1: required

bool  truerange = true

Hint: forget it. Deprecated, do not use. Maybe once removed.

When converting from true 10-16 bit formats, truerange=false indicates bitdepth of 16 bits regardless of the 10-12-14 bit format. Not applicable for non planar formats.

int  dither = -1

• If -1 (default), do not add dither;
• If 0, add ordered dither;
• If 1, add error diffusion (Floyd-Steinberg) dither ^doom9

Dithering is allowed only for scaling down (bit depth reduction), not up. Bit depth can be kept though if a smaller dither_bits is given.

From 3.7.1: no limit. Note: (behind the scenes) 32 bit float clips are first converted down to 16 (or less if needed) bits, then are further dithered down from this intermediate clip.

<3.7.1: Dithering is allowed only for 10-16bit (not 32bit float) sources.

int  dither_bits = bits

Exaggerated dither effect: dither to a lower color depth than required by bits argument.

Has no effect if dither=-1 (off).

• from 3.7.1 Arbitrary number from 1 to bits, inclusive.
• <3.7.1: Must be an even number from 2 to bits, inclusive.
• <3.7.1: In addition, must be >= (clip.BitsPerComponent-8).

bool  fulls = (auto)

Use the default value unless you know what you are doing.

Default value can come from _ChromaRange frame property

If true (RGB default), scale by multiplication: 0-255 → 0-65535;

Note: full scale U and V chroma is specially handled

if false (YUV default), scale by bit-shifting.

Use case: override greyscale conversion to fullscale instead of bit-shifts.

Conversion from and to float is always full-scale.

Alpha plane is always treated as full scale.

bool  fulld = fulls

Use the default value unless you know what you are doing.

From 3.7.1: can be any combination with fulls.

<3.7.1: must match fulls.

ConvertBits writes _ChromaRange frame property (0-full or 1-limited)

[edit] Changes