aom_dsp/aom_filter.h

/*
 * Copyright (c) 2021, Alliance for Open Media. All rights reserved
 *
 * This source code is subject to the terms of the BSD 3-Clause Clear License
 * and the Alliance for Open Media Patent License 1.0. If the BSD 3-Clause Clear
 * License was not distributed with this source code in the LICENSE file, you
 * can obtain it at aomedia.org/license/software-license/bsd-3-c-c/.  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
 * aomedia.org/license/patent-license/.
 */

#ifndef AOM_AOM_DSP_AOM_FILTER_H_
#define AOM_AOM_DSP_AOM_FILTER_H_

#include "aom/aom_integer.h"

#ifdef __cplusplus
extern "C" {
#endif

#define FILTER_BITS 7

#define SUBPEL_BITS 4
#define SUBPEL_MASK ((1 << SUBPEL_BITS) - 1)
#define SUBPEL_SHIFTS (1 << SUBPEL_BITS)
#define SUBPEL_TAPS 8

#define SCALE_SUBPEL_BITS 10
#define SCALE_SUBPEL_SHIFTS (1 << SCALE_SUBPEL_BITS)
#define SCALE_SUBPEL_MASK (SCALE_SUBPEL_SHIFTS - 1)
#define SCALE_EXTRA_BITS (SCALE_SUBPEL_BITS - SUBPEL_BITS)
#define SCALE_EXTRA_OFF ((1 << SCALE_EXTRA_BITS) / 2)

#define RS_SUBPEL_BITS 6
#define RS_SUBPEL_MASK ((1 << RS_SUBPEL_BITS) - 1)
#define RS_SCALE_SUBPEL_BITS 14
#define RS_SCALE_SUBPEL_MASK ((1 << RS_SCALE_SUBPEL_BITS) - 1)
#define RS_SCALE_EXTRA_BITS (RS_SCALE_SUBPEL_BITS - RS_SUBPEL_BITS)
#define RS_SCALE_EXTRA_OFF (1 << (RS_SCALE_EXTRA_BITS - 1))

typedef int16_t InterpKernel[SUBPEL_TAPS];

#define BIL_SUBPEL_BITS 3
#define BIL_SUBPEL_SHIFTS (1 << BIL_SUBPEL_BITS)

// 2 tap bilinear filters
static const uint8_t bilinear_filters_2t[BIL_SUBPEL_SHIFTS][2] = {
  { 128, 0 }, { 112, 16 }, { 96, 32 }, { 80, 48 },
  { 64, 64 }, { 48, 80 },  { 32, 96 }, { 16, 112 },
};

#ifdef __cplusplus
}  // extern "C"
#endif

#endif  // AOM_AOM_DSP_AOM_FILTER_H_