Struct VardctQuantizer 

pub struct VardctQuantizer {
    pub global_scale: u32,
    pub quant_lf: u32,
}

VarDCT quantizer fields recovered from a JPEG XL frame’s LfGlobal section (the lossy quantization state).

These are the raw bitstream values. Mapping them to an encoder “quality” or Butteraugli distance is encoder-specific and approximate, so it lives in higher-level crates rather than the decoder.

Fields

global_scale: u32

The frame’s global_scale field. Larger = coarser quantization (lower quality). Always >= 1.

quant_lf: u32

The frame’s quant_lf field — the low-frequency quantization multiplier. Always >= 1.

Implementations

impl VardctQuantizer

pub fn inv_global_scale(&self) -> f32

2^16 / global_scale: the inverse global scale. Larger = finer quantization (higher quality). This is the objective dequantization factor, independent of any encoder’s quality mapping.

Trait Implementations

impl Clone for VardctQuantizer

fn clone(&self) -> VardctQuantizer

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for VardctQuantizer

impl Debug for VardctQuantizer

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for VardctQuantizer

impl PartialEq for VardctQuantizer

fn eq(&self, other: &VardctQuantizer) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for VardctQuantizer