/** Lazily-built forward transform matrix (rows = coefficients, cols = pixels). */
export declare function forwardMatrix(): Float64Array[];
/**
 * Forward-transform a 16-pixel residual block (row-major) into raster-order
 * transform coefficients. Coefficient index `rc` matches the decoder's cf[]
 * indexing used by the scan tables and `itxfmAdd`.
 */
export declare function forward4x4(residual: Int32Array | number[], out: Float64Array): void;