av1/common/cfl.h

/*
 * Copyright (c) 2016, Alliance for Open Media. All rights reserved
 *
 * This source code is subject to the terms of the BSD 2 Clause License and
 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
 * was not distributed with this source code in the LICENSE file, you can
 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
 * Media Patent License 1.0 was not distributed with this source code in the
 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
 */

#ifndef AV1_COMMON_CFL_H_
#define AV1_COMMON_CFL_H_

#include <assert.h>

#include "av1/common/enums.h"

// Forward declaration of AV1_COMMON, in order to avoid creating a cyclic
// dependency by importing av1/common/onyxc_int.h
typedef struct AV1Common AV1_COMMON;

// Forward declaration of MACROBLOCK, in order to avoid creating a cyclic
// dependency by importing av1/common/blockd.h
typedef struct macroblockd MACROBLOCKD;

typedef struct {
  // Pixel buffer containing the luma pixels used as prediction for chroma
  // TODO(ltrudeau) Convert to uint16 for HBD support
  uint8_t y_pix[MAX_SB_SQUARE];

  // Pixel buffer containing the downsampled luma pixels used as prediction for
  // chroma
  // TODO(ltrudeau) Convert to uint16 for HBD support
  uint8_t y_down_pix[MAX_SB_SQUARE];

  // Height and width of the luma prediction block currently in the pixel buffer
  int y_height, y_width;

  // Height and width of the chroma prediction block currently associated with
  // this context
  int uv_height, uv_width;

  // Transform level averages of the luma reconstructed values over the entire
  // prediction unit
  // Fixed point y_averages is Q12.3:
  //   * Worst case division is 1/1024
  //   * Max error will be 1/16th.
  // Note: 3 is chosen so that y_averages fits in 15 bits when 12 bit input is
  // used
  int y_averages_q3[MAX_NUM_TXB];
  int y_averages_stride;

  int are_parameters_computed;

  // Chroma subsampling
  int subsampling_x, subsampling_y;

  // Block level DC_PRED for each chromatic plane
  int dc_pred[CFL_PRED_PLANES];

  // The rate associated with each alpha codeword
  int costs[CFL_ALPHABET_SIZE];

  int mi_row, mi_col;
} CFL_CTX;

static const double cfl_alpha_mags[CFL_MAGS_SIZE] = {
  0., 0.125, -0.125, 0.25, -0.25, 0.5, -0.5
};

static const int cfl_alpha_codes[CFL_ALPHABET_SIZE][CFL_PRED_PLANES] = {
  // barrbrain's simple 1D quant ordered by subset 3 likelihood
  { 0, 0 }, { 1, 1 }, { 3, 0 }, { 3, 3 }, { 1, 0 }, { 3, 1 },
  { 5, 5 }, { 0, 1 }, { 5, 3 }, { 5, 0 }, { 3, 5 }, { 1, 3 },
  { 0, 3 }, { 5, 1 }, { 1, 5 }, { 0, 5 }
};

static INLINE int get_scaled_luma_q0(int alpha_q3, int y_pix, int avg_q3) {
  return (alpha_q3 * ((y_pix << 3) - avg_q3) + 32) >> 6;
}

void cfl_init(CFL_CTX *cfl, AV1_COMMON *cm);

void cfl_predict_block(MACROBLOCKD *const xd, uint8_t *dst, int dst_stride,
                       int row, int col, TX_SIZE tx_size, int plane);

void cfl_store(CFL_CTX *cfl, const uint8_t *input, int input_stride, int row,
               int col, TX_SIZE tx_size, BLOCK_SIZE bsize);

void cfl_compute_parameters(MACROBLOCKD *const xd, TX_SIZE tx_size);

#endif  // AV1_COMMON_CFL_H_