Enum ZeroBiasConfig 

#[non_exhaustive]
pub enum ZeroBiasConfig {
    Perceptual,
    Disabled,
    Custom {
        luma: ([f32; 64], [f32; 64]),
        cb: ([f32; 64], [f32; 64]),
        cr: ([f32; 64], [f32; 64]),
    },
}

Zero-bias configuration for quantization.

Zero-bias controls how coefficients are rounded toward zero during quantization. Higher multipliers mean more aggressive zeroing of small coefficients, which improves compression but may reduce quality.

The jpegli defaults are perceptually optimized and vary by:

• Quality level (blends between HQ and LQ tables based on butteraugli distance)
• Component (Y, Cb, Cr have different optimal bias values)
• Coefficient position (different DCT frequencies have different biases)

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Perceptual

Use jpegli’s perceptual zero-bias tables (default). These are quality-adaptive: they blend between HQ and LQ tables based on the effective butteraugli distance.

Disabled

Disable zero-bias (all multipliers = 0, all offsets = 0). This matches standard JPEG behavior without adaptive quantization.

Custom

Custom zero-bias tables. Each component has 64 multiplier values and 64 offset values.

Fields

luma: ([f32; 64], [f32; 64])

Luma (Y) zero-bias: (multipliers[64], offsets[64])

cb: ([f32; 64], [f32; 64])

Blue chroma (Cb) zero-bias: (multipliers[64], offsets[64])

cr: ([f32; 64], [f32; 64])

Red chroma (Cr) zero-bias: (multipliers[64], offsets[64])

Trait Implementations

impl Clone for ZeroBiasConfig

fn clone(&self) -> ZeroBiasConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ZeroBiasConfig

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

Formats the value using the given formatter.

impl Default for ZeroBiasConfig

fn default() -> ZeroBiasConfig

Returns the “default value” for a type.