Struct FixedFrame 

pub struct FixedFrame {
    pub bpp_max: f64,
    pub s2_max: f64,
    pub ba_max: f64,
    pub aspect: f64,
}

Fixed normalization frame for web-targeted R-D analysis.

Uses metric-native scales and an aspect ratio calibrated so the reference knee (mozjpeg 4:2:0 on CID22) lands at exactly 45 degrees. Angles are comparable across codecs and corpora.

Fields

bpp_max: f64

Maximum bpp (practical ceiling). Default: 4.0 for web.

s2_max: f64

SSIMULACRA2 scale maximum. Always 100.

ba_max: f64

Butteraugli practical worst-case. Default: 15.0.

aspect: f64

Quality-axis stretch factor. Calibrated from reference knee so that atan2(q_norm * aspect, 1 - bpp_norm) = 45 deg at the knee.

Implementations

impl FixedFrame

pub const WEB: Self

Standard web-targeting frame.

Aspect ratio calibrated from CID22-training mozjpeg 4:2:0 s2 knee at (0.7274 bpp, s2=65.10): aspect = (1 - 0.7274/4.0) / (65.10/100.0) = 1.2568

pub fn s2_angle(&self, bpp: f64, s2: f64) -> f64

Compute the corner angle for an SSIMULACRA2 measurement.

Origin is the worst corner: (bpp_max, s2=0). The aspect ratio stretches the quality axis so the reference knee is at 45 degrees. Angles can exceed 90 degrees or go below 0 degrees for extreme encodes.

pub fn ba_angle(&self, bpp: f64, ba: f64) -> f64

Compute the corner angle for a Butteraugli measurement.

Butteraugli is inverted: lower = better. We normalize so that ba=0 means quality_norm=1.0, ba=ba_max means quality_norm=0.0. Same aspect ratio as s2 for comparable dual-angle analysis.

pub fn position(&self, bpp: f64, s2: f64, ba: f64) -> RDPosition

Compute dual-angle position for an encode.

Trait Implementations

impl Clone for FixedFrame

fn clone(&self) -> FixedFrame

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FixedFrame

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

Formats the value using the given formatter.

impl Default for FixedFrame

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for FixedFrame

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for FixedFrame

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for FixedFrame