vp9/common/vp9_filter.h

/*
 *  Copyright (c) 2011 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#ifndef VP9_COMMON_VP9_FILTER_H_
#define VP9_COMMON_VP9_FILTER_H_

#include "./vpx_config.h"
#include "vpx/vpx_integer.h"

#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

typedef enum {
  EIGHTTAP = 0,
  EIGHTTAP_SMOOTH = 1,
  EIGHTTAP_SHARP = 2,
  BILINEAR = 3,
  SWITCHABLE = 4  /* should be the last one */
} INTERPOLATION_TYPE;

typedef int16_t subpel_kernel[SUBPEL_TAPS];

struct subpix_fn_table {
  const subpel_kernel *filter_x;
  const subpel_kernel *filter_y;
};

const subpel_kernel *vp9_get_filter_kernel(INTERPOLATION_TYPE type);

extern const subpel_kernel vp9_bilinear_filters[SUBPEL_SHIFTS];
extern const subpel_kernel vp9_sub_pel_filters_8[SUBPEL_SHIFTS];
extern const subpel_kernel vp9_sub_pel_filters_8s[SUBPEL_SHIFTS];
extern const subpel_kernel vp9_sub_pel_filters_8lp[SUBPEL_SHIFTS];

// The VP9_BILINEAR_FILTERS_2TAP macro returns a pointer to the bilinear
// filter kernel as a 2 tap filter.
#define BILINEAR_FILTERS_2TAP(x) \
  (vp9_bilinear_filters[(x)] + SUBPEL_TAPS/2 - 1)

#endif  // VP9_COMMON_VP9_FILTER_H_