/** Look up the default probability for a given (block_type, band, ctx, prob_idx). */
export declare function defaultCoefProb(blockType: number, band: number, ctx: number, probIdx: number): number;
/** Clamp a quantiser-table index into the valid 0..127 range. */
export declare function clampQi(qi: number): number;
/**
 * Get the 9-element B-mode probability vector for a given (above, left)
 * neighbour pair. Returns a Uint8Array slice — callers should index into
 * it as `probs[i]` for i in 0..8.
 */
export declare function kfBmodeProbs(above: number, left: number): Uint8Array;
/** Look up a single B-mode probability for `[above][left][i]`. */
export declare function kfBmodeProb(above: number, left: number, idx: number): number;
/**
 * VP8 constant tables.
 *
 * Every value here is a verbatim transcription of libwebp's
 * `src/dec/tree_dec.c` (default coef probs, coef update probs,
 * keyframe B-mode probs, kBands, kZigzag) and `src/dec/vp8_dec.c`
 * (CAT1..CAT6 extra-bit probabilities). Maintaining bit-exact
 * agreement with libwebp's reference data is the cheapest way to
 * stay bit-exact with `cwebp`/`dwebp`-produced files; the tables
 * are big, but every byte matters.
 *
 * Sections referenced inline are RFC 6386 sections.
 */
// ---------------------------------------------------------------------------
// Block-type / coefficient infrastructure
// ---------------------------------------------------------------------------
export declare const NUM_BLOCK_TYPES: 4;
export declare const NUM_COEF_BANDS: 8;
export declare const NUM_DCT_TOKENS: 12;
/**
 * For each of the 16 coefficient positions in a 4×4 block (in zig-zag
 * order), which of the 8 "bands" it belongs to. Position 16 is a
 * sentinel that maps back to band 0 — libwebp keeps the extra entry so
 * `bands_ptr[type][n+1]` is always valid even when the loop has just
 * advanced past position 15.
 */
export declare const COEF_BANDS: Uint8Array;
/** Zig-zag scan order: zig-zag position → output (raster) index. */
export declare const ZIGZAG: Uint8Array;
/**
 * CAT3..CAT6 extra-magnitude bit probabilities, terminated by a 0
 * sentinel (libwebp's loop runs `for (tab = kCat3456[cat]; *tab; ++tab)`).
 */
export declare const CAT3_PROBS: Uint8Array;
export declare const CAT4_PROBS: Uint8Array;
export declare const CAT5_PROBS: Uint8Array;
export declare const CAT6_PROBS: Uint8Array;
export declare const CAT3456_PROBS: ReadonlyArray<Uint8Array>;
// ---------------------------------------------------------------------------
// Default coefficient probabilities — libwebp `CoeffsProba0`
// ---------------------------------------------------------------------------
//
// Layout: [block_type][band][ctx][prob_idx] flattened to a single
// Uint8Array. The flat index is
//
//   block_type * NUM_COEF_BANDS * 3 * 11
//   + band     * 3 * 11
//   + ctx      * 11
//   + prob_idx
//
// Block types follow libwebp's convention:
//   0 = "Y after Y2" (16 luma blocks when 16×16 prediction is used)
//   1 = "Y2"          (the WHT block of luma DCs)
//   2 = "UV"          (8 chroma blocks)
//   3 = "Y NO Y2"    (16 luma blocks when B_PRED prediction is used)
//
// libwebp keeps band 0 of "Y after Y2" as an all-128 sentinel because
// those blocks always start at zig-zag position 1 (DC lives in Y2).
export declare const DEFAULT_COEF_PROBS: () => unknown;
// ---------------------------------------------------------------------------
// Coef-probability update probabilities — libwebp `CoeffsUpdateProba`
// ---------------------------------------------------------------------------
export declare const COEF_UPDATE_PROBS: () => unknown;
/**
 * AC dequantisation lookup — libwebp `kAcTable`. NOTE: this is a
 * different table from the DC lookup; the values rise faster at the
 * high-quality end. Conflating them is a common bug.
 */
export declare const AC_QUANT: Uint16Array;
/** DC dequantisation lookup — libwebp `kDcTable`. */
export declare const DC_QUANT: Uint16Array;
/** Aliases retained for backward compatibility with earlier modules. */
export declare const Y_AC_QUANT: unknown;
export declare const Y_DC_QUANT: unknown;
export declare const UV_AC_QUANT: unknown;
export declare const UV_DC_QUANT: unknown;
export declare const Y2_AC_QUANT: unknown;
export declare const Y2_DC_QUANT: unknown;
/**
 * Luma 16×16 prediction modes. libwebp aliases these onto the 4×4
 * B-mode enum values (DC=B_DC, V=B_VE, H=B_HE, TM=B_TM) so that when
 * a non-B_PRED MB writes its ymode into the intra_t/intra_l B-mode
 * tracker, the value propagates correctly into the next MB's
 * `kBModesProba` lookup.
 */
export declare const DC_PRED: unknown;
/**
 * Per-4×4 luma intra modes. libwebp's enum has B_RD/B_VR/B_LD at
 * positions 4/5/6 (NOT the RFC 6386 / libvpx ordering of LD/RD/VR).
 * This matters because the bit-tree decodes mode indices that get
 * stored in `intra_t`/`intra_l` and used to index `kBModesProba`,
 * so the value MUST match libwebp's convention to be bit-exact.
 */
export declare const B_DC_PRED: 0;
export declare const B_TM_PRED: 1;
export declare const B_VE_PRED: 2;
export declare const B_HE_PRED: 3;
export declare const B_RD_PRED: 4;
export declare const B_VR_PRED: 5;
export declare const B_LD_PRED: 6;
export declare const B_VL_PRED: 7;
export declare const B_HD_PRED: 8;
export declare const B_HU_PRED: 9;
export declare const NUM_BMODES: 10;
/**
 * Y mode tree and probabilities (4 modes, used when 16×16 prediction
 * is in effect). libwebp inlines this as a hand-unrolled tree decode
 * for speed; we keep both shapes available so consumers can pick.
 */
export declare const KF_Y_MODE_TREE: Int8Array;
export declare const KF_Y_MODE_PROBS: Uint8Array;
/** UV mode tree (same set as luma 16×16). */
export declare const UV_MODE_TREE: Int8Array;
export declare const KF_UV_MODE_PROBS: Uint8Array;
/** B-mode (per-subblock 4×4 luma) tree (10 modes). */
export declare const B_MODE_TREE: Int8Array;
// ---------------------------------------------------------------------------
// Keyframe B-mode probabilities — libwebp `kBModesProba`
// ---------------------------------------------------------------------------
//
// 10 above-modes × 10 left-modes × 9 probs = 900 entries.
export declare const KF_BMODE_PROBS: () => unknown;
/** Same as COEF_BANDS above; exposed under the libwebp-style canonical name. */
export { COEF_BANDS as DCT_COEF_BAND };