path: root/media/libvpx/libvpx/vp8/common/loopfilter_filters.c

/*
 *  Copyright (c) 2010 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.
 */

#include <stdlib.h>
#include "loopfilter.h"
#include "onyxc_int.h"

typedef unsigned char uc;

static signed char vp8_signed_char_clamp(int t) {
  t = (t < -128 ? -128 : t);
  t = (t > 127 ? 127 : t);
  return (signed char)t;
}

/* should we apply any filter at all ( 11111111 yes, 00000000 no) */
static signed char vp8_filter_mask(uc limit, uc blimit, uc p3, uc p2, uc p1,
                                   uc p0, uc q0, uc q1, uc q2, uc q3) {
  signed char mask = 0;
  mask |= (abs(p3 - p2) > limit);
  mask |= (abs(p2 - p1) > limit);
  mask |= (abs(p1 - p0) > limit);
  mask |= (abs(q1 - q0) > limit);
  mask |= (abs(q2 - q1) > limit);
  mask |= (abs(q3 - q2) > limit);
  mask |= (abs(p0 - q0) * 2 + abs(p1 - q1) / 2 > blimit);
  return mask - 1;
}

/* is there high variance internal edge ( 11111111 yes, 00000000 no) */
static signed char vp8_hevmask(uc thresh, uc p1, uc p0, uc q0, uc q1) {
  signed char hev = 0;
  hev |= (abs(p1 - p0) > thresh) * -1;
  hev |= (abs(q1 - q0) > thresh) * -1;
  return hev;
}

static void vp8_filter(signed char mask, uc hev, uc *op1, uc *op0, uc *oq0,
                       uc *oq1) {
  signed char ps0, qs0;
  signed char ps1, qs1;
  signed char filter_value, Filter1, Filter2;
  signed char u;

  ps1 = (signed char)*op1 ^ 0x80;
  ps0 = (signed char)*op0 ^ 0x80;
  qs0 = (signed char)*oq0 ^ 0x80;
  qs1 = (signed char)*oq1 ^ 0x80;

  /* add outer taps if we have high edge variance */
  filter_value = vp8_signed_char_clamp(ps1 - qs1);
  filter_value &= hev;

  /* inner taps */
  filter_value = vp8_signed_char_clamp(filter_value + 3 * (qs0 - ps0));
  filter_value &= mask;

  /* save bottom 3 bits so that we round one side +4 and the other +3
   * if it equals 4 we'll set it to adjust by -1 to account for the fact
   * we'd round it by 3 the other way
   */
  Filter1 = vp8_signed_char_clamp(filter_value + 4);
  Filter2 = vp8_signed_char_clamp(filter_value + 3);
  Filter1 >>= 3;
  Filter2 >>= 3;
  u = vp8_signed_char_clamp(qs0 - Filter1);
  *oq0 = u ^ 0x80;
  u = vp8_signed_char_clamp(ps0 + Filter2);
  *op0 = u ^ 0x80;
  filter_value = Filter1;

  /* outer tap adjustments */
  filter_value += 1;
  filter_value >>= 1;
  filter_value &= ~hev;

  u = vp8_signed_char_clamp(qs1 - filter_value);
  *oq1 = u ^ 0x80;
  u = vp8_signed_char_clamp(ps1 + filter_value);
  *op1 = u ^ 0x80;
}

static void loop_filter_horizontal_edge_c(unsigned char *s, int p, /* pitch */
                                          const unsigned char *blimit,
                                          const unsigned char *limit,
                                          const unsigned char *thresh,
                                          int count) {
  int hev = 0; /* high edge variance */
  signed char mask = 0;
  int i = 0;

  /* loop filter designed to work using chars so that we can make maximum use
   * of 8 bit simd instructions.
   */
  do {
    mask = vp8_filter_mask(limit[0], blimit[0], s[-4 * p], s[-3 * p], s[-2 * p],
                           s[-1 * p], s[0 * p], s[1 * p], s[2 * p], s[3 * p]);

    hev = vp8_hevmask(thresh[0], s[-2 * p], s[-1 * p], s[0 * p], s[1 * p]);

    vp8_filter(mask, hev, s - 2 * p, s - 1 * p, s, s + 1 * p);

    ++s;
  } while (++i < count * 8);
}

static void loop_filter_vertical_edge_c(unsigned char *s, int p,
                                        const unsigned char *blimit,
                                        const unsigned char *limit,
                                        const unsigned char *thresh,
                                        int count) {
  int hev = 0; /* high edge variance */
  signed char mask = 0;
  int i = 0;

  /* loop filter designed to work using chars so that we can make maximum use
   * of 8 bit simd instructions.
   */
  do {
    mask = vp8_filter_mask(limit[0], blimit[0], s[-4], s[-3], s[-2], s[-1],
                           s[0], s[1], s[2], s[3]);

    hev = vp8_hevmask(thresh[0], s[-2], s[-1], s[0], s[1]);

    vp8_filter(mask, hev, s - 2, s - 1, s, s + 1);

    s += p;
  } while (++i < count * 8);
}

static void vp8_mbfilter(signed char mask, uc hev, uc *op2, uc *op1, uc *op0,
                         uc *oq0, uc *oq1, uc *oq2) {
  signed char s, u;
  signed char filter_value, Filter1, Filter2;
  signed char ps2 = (signed char)*op2 ^ 0x80;
  signed char ps1 = (signed char)*op1 ^ 0x80;
  signed char ps0 = (signed char)*op0 ^ 0x80;
  signed char qs0 = (signed char)*oq0 ^ 0x80;
  signed char qs1 = (signed char)*oq1 ^ 0x80;
  signed char qs2 = (signed char)*oq2 ^ 0x80;

  /* add outer taps if we have high edge variance */
  filter_value = vp8_signed_char_clamp(ps1 - qs1);
  filter_value = vp8_signed_char_clamp(filter_value + 3 * (qs0 - ps0));
  filter_value &= mask;

  Filter2 = filter_value;
  Filter2 &= hev;

  /* save bottom 3 bits so that we round one side +4 and the other +3 */
  Filter1 = vp8_signed_char_clamp(Filter2 + 4);
  Filter2 = vp8_signed_char_clamp(Filter2 + 3);
  Filter1 >>= 3;
  Filter2 >>= 3;
  qs0 = vp8_signed_char_clamp(qs0 - Filter1);
  ps0 = vp8_signed_char_clamp(ps0 + Filter2);

  /* only apply wider filter if not high edge variance */
  filter_value &= ~hev;
  Filter2 = filter_value;

  /* roughly 3/7th difference across boundary */
  u = vp8_signed_char_clamp((63 + Filter2 * 27) >> 7);
  s = vp8_signed_char_clamp(qs0 - u);
  *oq0 = s ^ 0x80;
  s = vp8_signed_char_clamp(ps0 + u);
  *op0 = s ^ 0x80;

  /* roughly 2/7th difference across boundary */
  u = vp8_signed_char_clamp((63 + Filter2 * 18) >> 7);
  s = vp8_signed_char_clamp(qs1 - u);
  *oq1 = s ^ 0x80;
  s = vp8_signed_char_clamp(ps1 + u);
  *op1 = s ^ 0x80;

  /* roughly 1/7th difference across boundary */
  u = vp8_signed_char_clamp((63 + Filter2 * 9) >> 7);
  s = vp8_signed_char_clamp(qs2 - u);
  *oq2 = s ^ 0x80;
  s = vp8_signed_char_clamp(ps2 + u);
  *op2 = s ^ 0x80;
}

static void mbloop_filter_horizontal_edge_c(unsigned char *s, int p,
                                            const unsigned char *blimit,
                                            const unsigned char *limit,
                                            const unsigned char *thresh,
                                            int count) {
  signed char hev = 0; /* high edge variance */
  signed char mask = 0;
  int i = 0;

  /* loop filter designed to work using chars so that we can make maximum use
   * of 8 bit simd instructions.
   */
  do {
    mask = vp8_filter_mask(limit[0], blimit[0], s[-4 * p], s[-3 * p], s[-2 * p],
                           s[-1 * p], s[0 * p], s[1 * p], s[2 * p], s[3 * p]);

    hev = vp8_hevmask(thresh[0], s[-2 * p], s[-1 * p], s[0 * p], s[1 * p]);

    vp8_mbfilter(mask, hev, s - 3 * p, s - 2 * p, s - 1 * p, s, s + 1 * p,
                 s + 2 * p);

    ++s;
  } while (++i < count * 8);
}

static void mbloop_filter_vertical_edge_c(unsigned char *s, int p,
                                          const unsigned char *blimit,
                                          const unsigned char *limit,
                                          const unsigned char *thresh,
                                          int count) {
  signed char hev = 0; /* high edge variance */
  signed char mask = 0;
  int i = 0;

  do {
    mask = vp8_filter_mask(limit[0], blimit[0], s[-4], s[-3], s[-2], s[-1],
                           s[0], s[1], s[2], s[3]);

    hev = vp8_hevmask(thresh[0], s[-2], s[-1], s[0], s[1]);

    vp8_mbfilter(mask, hev, s - 3, s - 2, s - 1, s, s + 1, s + 2);

    s += p;
  } while (++i < count * 8);
}

/* should we apply any filter at all ( 11111111 yes, 00000000 no) */
static signed char vp8_simple_filter_mask(uc blimit, uc p1, uc p0, uc q0,
                                          uc q1) {
  /* Why does this cause problems for win32?
   * error C2143: syntax error : missing ';' before 'type'
   *  (void) limit;
   */
  signed char mask = (abs(p0 - q0) * 2 + abs(p1 - q1) / 2 <= blimit) * -1;
  return mask;
}

static void vp8_simple_filter(signed char mask, uc *op1, uc *op0, uc *oq0,
                              uc *oq1) {
  signed char filter_value, Filter1, Filter2;
  signed char p1 = (signed char)*op1 ^ 0x80;
  signed char p0 = (signed char)*op0 ^ 0x80;
  signed char q0 = (signed char)*oq0 ^ 0x80;
  signed char q1 = (signed char)*oq1 ^ 0x80;
  signed char u;

  filter_value = vp8_signed_char_clamp(p1 - q1);
  filter_value = vp8_signed_char_clamp(filter_value + 3 * (q0 - p0));
  filter_value &= mask;

  /* save bottom 3 bits so that we round one side +4 and the other +3 */
  Filter1 = vp8_signed_char_clamp(filter_value + 4);
  Filter1 >>= 3;
  u = vp8_signed_char_clamp(q0 - Filter1);
  *oq0 = u ^ 0x80;

  Filter2 = vp8_signed_char_clamp(filter_value + 3);
  Filter2 >>= 3;
  u = vp8_signed_char_clamp(p0 + Filter2);
  *op0 = u ^ 0x80;
}

void vp8_loop_filter_simple_horizontal_edge_c(unsigned char *y_ptr,
                                              int y_stride,
                                              const unsigned char *blimit) {
  signed char mask = 0;
  int i = 0;

  do {
    mask = vp8_simple_filter_mask(blimit[0], y_ptr[-2 * y_stride],
                                  y_ptr[-1 * y_stride], y_ptr[0 * y_stride],
                                  y_ptr[1 * y_stride]);
    vp8_simple_filter(mask, y_ptr - 2 * y_stride, y_ptr - 1 * y_stride, y_ptr,
                      y_ptr + 1 * y_stride);
    ++y_ptr;
  } while (++i < 16);
}

void vp8_loop_filter_simple_vertical_edge_c(unsigned char *y_ptr, int y_stride,
                                            const unsigned char *blimit) {
  signed char mask = 0;
  int i = 0;

  do {
    mask = vp8_simple_filter_mask(blimit[0], y_ptr[-2], y_ptr[-1], y_ptr[0],
                                  y_ptr[1]);
    vp8_simple_filter(mask, y_ptr - 2, y_ptr - 1, y_ptr, y_ptr + 1);
    y_ptr += y_stride;
  } while (++i < 16);
}

/* Horizontal MB filtering */
void vp8_loop_filter_mbh_c(unsigned char *y_ptr, unsigned char *u_ptr,
                           unsigned char *v_ptr, int y_stride, int uv_stride,
                           loop_filter_info *lfi) {
  mbloop_filter_horizontal_edge_c(y_ptr, y_stride, lfi->mblim, lfi->lim,
                                  lfi->hev_thr, 2);

  if (u_ptr) {
    mbloop_filter_horizontal_edge_c(u_ptr, uv_stride, lfi->mblim, lfi->lim,
                                    lfi->hev_thr, 1);
  }

  if (v_ptr) {
    mbloop_filter_horizontal_edge_c(v_ptr, uv_stride, lfi->mblim, lfi->lim,
                                    lfi->hev_thr, 1);
  }
}

/* Vertical MB Filtering */
void vp8_loop_filter_mbv_c(unsigned char *y_ptr, unsigned char *u_ptr,
                           unsigned char *v_ptr, int y_stride, int uv_stride,
                           loop_filter_info *lfi) {
  mbloop_filter_vertical_edge_c(y_ptr, y_stride, lfi->mblim, lfi->lim,
                                lfi->hev_thr, 2);

  if (u_ptr) {
    mbloop_filter_vertical_edge_c(u_ptr, uv_stride, lfi->mblim, lfi->lim,
                                  lfi->hev_thr, 1);
  }

  if (v_ptr) {
    mbloop_filter_vertical_edge_c(v_ptr, uv_stride, lfi->mblim, lfi->lim,
                                  lfi->hev_thr, 1);
  }
}

/* Horizontal B Filtering */
void vp8_loop_filter_bh_c(unsigned char *y_ptr, unsigned char *u_ptr,
                          unsigned char *v_ptr, int y_stride, int uv_stride,
                          loop_filter_info *lfi) {
  loop_filter_horizontal_edge_c(y_ptr + 4 * y_stride, y_stride, lfi->blim,
                                lfi->lim, lfi->hev_thr, 2);
  loop_filter_horizontal_edge_c(y_ptr + 8 * y_stride, y_stride, lfi->blim,
                                lfi->lim, lfi->hev_thr, 2);
  loop_filter_horizontal_edge_c(y_ptr + 12 * y_stride, y_stride, lfi->blim,
                                lfi->lim, lfi->hev_thr, 2);

  if (u_ptr) {
    loop_filter_horizontal_edge_c(u_ptr + 4 * uv_stride, uv_stride, lfi->blim,
                                  lfi->lim, lfi->hev_thr, 1);
  }

  if (v_ptr) {
    loop_filter_horizontal_edge_c(v_ptr + 4 * uv_stride, uv_stride, lfi->blim,
                                  lfi->lim, lfi->hev_thr, 1);
  }
}

void vp8_loop_filter_bhs_c(unsigned char *y_ptr, int y_stride,
                           const unsigned char *blimit) {
  vp8_loop_filter_simple_horizontal_edge_c(y_ptr + 4 * y_stride, y_stride,
                                           blimit);
  vp8_loop_filter_simple_horizontal_edge_c(y_ptr + 8 * y_stride, y_stride,
                                           blimit);
  vp8_loop_filter_simple_horizontal_edge_c(y_ptr + 12 * y_stride, y_stride,
                                           blimit);
}

/* Vertical B Filtering */
void vp8_loop_filter_bv_c(unsigned char *y_ptr, unsigned char *u_ptr,
                          unsigned char *v_ptr, int y_stride, int uv_stride,
                          loop_filter_info *lfi) {
  loop_filter_vertical_edge_c(y_ptr + 4, y_stride, lfi->blim, lfi->lim,
                              lfi->hev_thr, 2);
  loop_filter_vertical_edge_c(y_ptr + 8, y_stride, lfi->blim, lfi->lim,
                              lfi->hev_thr, 2);
  loop_filter_vertical_edge_c(y_ptr + 12, y_stride, lfi->blim, lfi->lim,
                              lfi->hev_thr, 2);

  if (u_ptr) {
    loop_filter_vertical_edge_c(u_ptr + 4, uv_stride, lfi->blim, lfi->lim,
                                lfi->hev_thr, 1);
  }

  if (v_ptr) {
    loop_filter_vertical_edge_c(v_ptr + 4, uv_stride, lfi->blim, lfi->lim,
                                lfi->hev_thr, 1);
  }
}

void vp8_loop_filter_bvs_c(unsigned char *y_ptr, int y_stride,
                           const unsigned char *blimit) {
  vp8_loop_filter_simple_vertical_edge_c(y_ptr + 4, y_stride, blimit);
  vp8_loop_filter_simple_vertical_edge_c(y_ptr + 8, y_stride, blimit);
  vp8_loop_filter_simple_vertical_edge_c(y_ptr + 12, y_stride, blimit);
}