Function score_frame_webp 

pub fn score_frame_webp(
    path: &Path,
    rgba: &[u8],
    width: u32,
    height: u32,
) -> Result<f64, SnapshotError>

Available on crate feature snapshot and non-WebAssembly only.

Score the frame rgba against the snapshot at path, on SSIMULACRA2’s 0–100 scale where higher is closer.

The snapshot must exist; a missing one is an std::io::Error rather than a cue to store the frame, so a caller that wants to store it says so itself.