decodetxb.c 5.29 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
/*
 * Copyright (c) 2017, 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.
 */

#include "av1/common/scan.h"
#include "av1/common/txb_common.h"
#include "av1/decoder/decodetxb.h"

#define ACCT_STR __func__

static int read_golomb(aom_reader *r) {
  int x = 1;
  int length = 0;
  int i = 0;

  while (!i) {
    i = aom_read_bit(r, ACCT_STR);
    ++length;
  }

  for (i = 0; i < length - 1; ++i) {
    x <<= 1;
    x += aom_read_bit(r, ACCT_STR);
  }

  return x - 1;
}

uint8_t av1_read_coeffs_txb(const AV1_COMMON *const cm, MACROBLOCKD *xd,
                            aom_reader *r, int block, int plane,
                            tran_low_t *tcoeffs, TXB_CTX *txb_ctx) {
  FRAME_COUNTS *counts = xd->counts;
Angie Chiang's avatar
Angie Chiang committed
40
  TX_SIZE tx_size = get_tx_size(plane, xd);
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
  PLANE_TYPE plane_type = get_plane_type(plane);
  aom_prob *nz_map = cm->fc->nz_map[tx_size][plane_type];
  aom_prob *eob_flag = cm->fc->eob_flag[tx_size][plane_type];
  MB_MODE_INFO *mbmi = &xd->mi[0]->mbmi;
  const TX_TYPE tx_type = get_tx_type(plane_type, xd, block, tx_size);
  const SCAN_ORDER *const scan_order =
      get_scan(cm, tx_size, tx_type, is_inter_block(mbmi));
  const int16_t *scan = scan_order->scan;
  const int seg_eob = 16 << (tx_size << 1);
  int c = 0;
  int eob = 0, update_eob = -1;
  const int16_t *const dequant = xd->plane[plane].seg_dequant[mbmi->segment_id];
  const int shift = (tx_size == TX_32X32);
  const int bwl = b_width_log2_lookup[txsize_to_bsize[tx_size]] + 2;
  int cul_level = 0;
  unsigned int(*nz_map_count)[SIG_COEF_CONTEXTS][2];
  uint8_t txb_mask[32 * 32] = { 0 };

  nz_map_count = (counts) ? &counts->nz_map[tx_size][plane_type] : NULL;

  memset(tcoeffs, 0, sizeof(*tcoeffs) * seg_eob);

  for (c = 0; c < seg_eob; ++c) {
    int is_nz;
    int coeff_ctx = get_nz_map_ctx(tcoeffs, txb_mask, scan[c], bwl);
    int eob_ctx = get_eob_ctx(tcoeffs, scan[c], bwl);

    if (c < seg_eob - 1)
      is_nz = aom_read(r, nz_map[coeff_ctx], tx_size);
    else
      is_nz = 1;

    // set non-zero coefficient map.
    tcoeffs[scan[c]] = is_nz;

    if (c == seg_eob - 1) {
      ++c;
      break;
    }

    if (counts) ++(*nz_map_count)[coeff_ctx][is_nz];

    if (is_nz) {
      int is_eob = aom_read(r, eob_flag[eob_ctx], tx_size);
      if (counts) ++counts->eob_flag[tx_size][plane_type][eob_ctx][is_eob];
      if (is_eob) break;
    }
    txb_mask[scan[c]] = 1;
  }

  eob = AOMMIN(seg_eob, c + 1);

  int i;
  for (i = 0; i < NUM_BASE_LEVELS; ++i) {
    aom_prob *coeff_base = cm->fc->coeff_base[tx_size][plane_type][i];

    update_eob = 0;
    for (c = eob - 1; c >= 0; --c) {
      tran_low_t *v = &tcoeffs[scan[c]];
      int sign;
      int ctx;

      if (*v <= i) continue;

      ctx = get_base_ctx(tcoeffs, scan[c], bwl, i + 1);

      if (aom_read(r, coeff_base[ctx], tx_size)) {
        *v = i + 1;
        cul_level += i + 1;

        if (counts) ++counts->coeff_base[tx_size][plane_type][i][ctx][1];

        if (c == 0) {
          int dc_sign_ctx = txb_ctx->dc_sign_ctx;
          sign = aom_read(r, cm->fc->dc_sign[plane_type][dc_sign_ctx], tx_size);
          if (counts) ++counts->dc_sign[plane_type][dc_sign_ctx][sign];
        } else {
          sign = aom_read_bit(r, ACCT_STR);
        }
        if (sign) *v = -(*v);
        continue;
      }
      *v = i + 2;
      if (counts) ++counts->coeff_base[tx_size][plane_type][i][ctx][0];

      // update the eob flag for coefficients with magnitude above 1.
      update_eob = AOMMAX(update_eob, c);
    }
  }

  for (c = update_eob; c >= 0; --c) {
    tran_low_t *v = &tcoeffs[scan[c]];
    int sign;
    int idx;
    int ctx;

    if (*v <= NUM_BASE_LEVELS) continue;

    if (c == 0) {
      int dc_sign_ctx = txb_ctx->dc_sign_ctx;
      sign = aom_read(r, cm->fc->dc_sign[plane_type][dc_sign_ctx], tx_size);
      if (counts) ++counts->dc_sign[plane_type][dc_sign_ctx][sign];
    } else {
      sign = aom_read_bit(r, ACCT_STR);
    }

    ctx = get_level_ctx(tcoeffs, scan[c], bwl);

    if (cm->fc->coeff_lps[tx_size][plane_type][ctx] == 0) exit(0);

    for (idx = 0; idx < COEFF_BASE_RANGE; ++idx) {
      if (aom_read(r, cm->fc->coeff_lps[tx_size][plane_type][ctx], tx_size)) {
        *v = (idx + 1 + NUM_BASE_LEVELS);
        if (sign) *v = -(*v);
        cul_level += abs(*v);

        if (counts) ++counts->coeff_lps[tx_size][plane_type][ctx][1];
        break;
      }
      if (counts) ++counts->coeff_lps[tx_size][plane_type][ctx][0];
    }
    if (idx < COEFF_BASE_RANGE) continue;

    // decode 0-th order Golomb code
    *v = read_golomb(r) + COEFF_BASE_RANGE + 1 + NUM_BASE_LEVELS;
    if (sign) *v = -(*v);
    cul_level += abs(*v);
  }

  for (c = 0; c < eob; ++c) {
    int16_t dqv = (c == 0) ? dequant[0] : dequant[1];
    tran_low_t *v = &tcoeffs[scan[c]];
    int sign = (*v) < 0;
    *v = (abs(*v) * dqv) >> shift;
    if (sign) *v = -(*v);
  }

  cul_level = AOMMIN(63, cul_level);

  // DC value
  set_dc_sign(&cul_level, tcoeffs[0]);

  return cul_level;
}