import { BoolDecoder } from './bool-decoder';
import type { VP8FrameHeader } from '../types';
export declare function parseVP8Header(data: Uint8Array): ParsedVP8Header;
/**
 * VP8 keyframe header parser — 1:1 port of libwebp's `VP8GetHeaders`,
 * `ParseSegmentHeader`, `ParseFilterHeader`, `ParsePartitions`,
 * `VP8ParseQuant`, and `VP8ParseProba` (src/dec/vp8_dec.c §9 + §13.5).
 *
 * Field order for a keyframe:
 *
 *   1. Frame tag (3 bytes uncompressed): keyframe?, profile,
 *      show_frame?, partition_length.
 *   2. Start code (3 bytes uncompressed): 0x9D 0x01 0x2A.
 *   3. Width/height + scales (4 bytes uncompressed).
 *   4. Bool-coded first partition begins:
 *      a. color_space (1 bit)
 *      b. clamp_type (1 bit)
 *      c. Segment header (variable)
 *      d. Filter header (variable, includes simple/level/sharpness/lf-delta)
 *      e. Partition table (2 bits log2_nparts + size headers if >1)
 *      f. Quantiser (7 bits + 5 deltas)
 *      g. update_proba bit (consumed and ignored on keyframes)
 *      h. Coefficient-probability update loop (4×8×3×11 entries)
 *      i. mb_no_skip_coef (1 bit) + prob_skip_false (8 bits if set)
 *
 * After this, mode info begins on the same first-partition bool decoder
 * (one MB at a time, `VP8ParseIntraModeRow`).
 */
/** A single segment's quant/filter override. */
export declare interface VP8Segment {
  quantiser: number
  filterStrength: number
}
export declare interface VP8SegmentHeader {
  useSegment: boolean
  updateMap: boolean
  absoluteDelta: boolean
  segments: VP8Segment[]
  segmentTreeProbs: Uint8Array
}
export declare interface VP8FilterHeader {
  simple: boolean
  level: number
  sharpness: number
  useLfDelta: boolean
  refLfDelta: Int8Array
  modeLfDelta: Int8Array
  filterType: 0 | 1 | 2
}
/** Per-segment dequantisation matrices, populated by `VP8ParseQuant`. */
export declare interface VP8QuantMatrix {
  y1: [number, number]
  y2: [number, number]
  uv: [number, number]
  uvQuant: number
}
export declare interface ParsedVP8Header {
  frame: VP8FrameHeader
  numPartitions: number
  partitionsOffset: number
  colorSpace: number
  clampType: number
  segmentation: VP8SegmentHeader
  filter: VP8FilterHeader
  quant: VP8QuantMatrix[]
  bool: BoolDecoder
  probSkipFalse: number | null
  coefProbs: Uint8Array
}