vp9/decoder/vp9_detokenize.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 "vpx_mem/vpx_mem.h"
#include "vpx_ports/mem.h"

#include "vp9/common/vp9_blockd.h"
#include "vp9/common/vp9_common.h"
#include "vp9/common/vp9_entropy.h"
#if CONFIG_COEFFICIENT_RANGE_CHECKING
#include "vp9/common/vp9_idct.h"
#endif

#include "vp9/decoder/vp9_detokenize.h"

#define EOB_CONTEXT_NODE            0
#define ZERO_CONTEXT_NODE           1
#define ONE_CONTEXT_NODE            2

#define INCREMENT_COUNT(token)                              \
  do {                                                      \
     if (counts)                                            \
       ++coef_counts[band][ctx][token];                     \
  } while (0)

static INLINE int read_coeff(const vpx_prob *probs, int n, vpx_reader *r) {
  int i, val = 0;
  for (i = 0; i < n; ++i)
    val = (val << 1) | vpx_read(r, probs[i]);
  return val;
}

static int decode_coefs(const MACROBLOCKD *xd,
                        PLANE_TYPE type,
                        tran_low_t *dqcoeff, TX_SIZE tx_size, const int16_t *dq,
                        int ctx, const int16_t *scan, const int16_t *nb,
                        vpx_reader *r) {
  FRAME_COUNTS *counts = xd->counts;
  const int max_eob = 16 << (tx_size << 1);
  const FRAME_CONTEXT *const fc = xd->fc;
  const int ref = is_inter_block(xd->mi[0]);
  int band, c = 0;
  const vpx_prob (*coef_probs)[COEFF_CONTEXTS][UNCONSTRAINED_NODES] =
      fc->coef_probs[tx_size][type][ref];
  const vpx_prob *prob;
  unsigned int (*coef_counts)[COEFF_CONTEXTS][UNCONSTRAINED_NODES + 1];
  unsigned int (*eob_branch_count)[COEFF_CONTEXTS];
  uint8_t token_cache[32 * 32];
  const uint8_t *band_translate = get_band_translate(tx_size);
  const int dq_shift = (tx_size == TX_32X32);
  int v, token;
  int16_t dqv = dq[0];
  const uint8_t *const cat6_prob =
#if CONFIG_VP9_HIGHBITDEPTH
      (xd->bd == VPX_BITS_12) ? vp9_cat6_prob_high12 :
      (xd->bd == VPX_BITS_10) ? vp9_cat6_prob_high12 + 2 :
#endif  // CONFIG_VP9_HIGHBITDEPTH
      vp9_cat6_prob;
  const int cat6_bits =
#if CONFIG_VP9_HIGHBITDEPTH
      (xd->bd == VPX_BITS_12) ? 18 :
      (xd->bd == VPX_BITS_10) ? 16 :
#endif  // CONFIG_VP9_HIGHBITDEPTH
      14;

  if (counts) {
    coef_counts = counts->coef[tx_size][type][ref];
    eob_branch_count = counts->eob_branch[tx_size][type][ref];
  }

  while (c < max_eob) {
    int val = -1;
    band = *band_translate++;
    prob = coef_probs[band][ctx];
    if (counts)
      ++eob_branch_count[band][ctx];
    if (!vpx_read(r, prob[EOB_CONTEXT_NODE])) {
      INCREMENT_COUNT(EOB_MODEL_TOKEN);
      break;
    }

    while (!vpx_read(r, prob[ZERO_CONTEXT_NODE])) {
      INCREMENT_COUNT(ZERO_TOKEN);
      dqv = dq[1];
      token_cache[scan[c]] = 0;
      ++c;
      if (c >= max_eob)
        return c;  // zero tokens at the end (no eob token)
      ctx = get_coef_context(nb, token_cache, c);
      band = *band_translate++;
      prob = coef_probs[band][ctx];
    }

    if (!vpx_read(r, prob[ONE_CONTEXT_NODE])) {
      INCREMENT_COUNT(ONE_TOKEN);
      token = ONE_TOKEN;
      val = 1;
    } else {
      INCREMENT_COUNT(TWO_TOKEN);
      token = vpx_read_tree(r, vp9_coef_con_tree,
                            vp9_pareto8_full[prob[PIVOT_NODE] - 1]);
      switch (token) {
        case TWO_TOKEN:
        case THREE_TOKEN:
        case FOUR_TOKEN:
          val = token;
          break;
        case CATEGORY1_TOKEN:
          val = CAT1_MIN_VAL + read_coeff(vp9_cat1_prob, 1, r);
          break;
        case CATEGORY2_TOKEN:
          val = CAT2_MIN_VAL + read_coeff(vp9_cat2_prob, 2, r);
          break;
        case CATEGORY3_TOKEN:
          val = CAT3_MIN_VAL + read_coeff(vp9_cat3_prob, 3, r);
          break;
        case CATEGORY4_TOKEN:
          val = CAT4_MIN_VAL + read_coeff(vp9_cat4_prob, 4, r);
          break;
        case CATEGORY5_TOKEN:
          val = CAT5_MIN_VAL + read_coeff(vp9_cat5_prob, 5, r);
          break;
        case CATEGORY6_TOKEN:
          val = CAT6_MIN_VAL + read_coeff(cat6_prob, cat6_bits, r);
          break;
      }
    }
    v = (val * dqv) >> dq_shift;
#if CONFIG_COEFFICIENT_RANGE_CHECKING
#if CONFIG_VP9_HIGHBITDEPTH
    dqcoeff[scan[c]] = highbd_check_range((vpx_read_bit(r) ? -v : v),
                                          xd->bd);
#else
    dqcoeff[scan[c]] = check_range(vpx_read_bit(r) ? -v : v);
#endif  // CONFIG_VP9_HIGHBITDEPTH
#else
    dqcoeff[scan[c]] = vpx_read_bit(r) ? -v : v;
#endif  // CONFIG_COEFFICIENT_RANGE_CHECKING
    token_cache[scan[c]] = vp9_pt_energy_class[token];
    ++c;
    ctx = get_coef_context(nb, token_cache, c);
    dqv = dq[1];
  }

  return c;
}

// TODO(slavarnway): Decode version of vp9_set_context.  Modify vp9_set_context
// after testing is complete, then delete this version.
static
void dec_set_contexts(const MACROBLOCKD *xd, struct macroblockd_plane *pd,
                      TX_SIZE tx_size, int has_eob,
                      int aoff, int loff) {
  ENTROPY_CONTEXT *const a = pd->above_context + aoff;
  ENTROPY_CONTEXT *const l = pd->left_context + loff;
  const int tx_size_in_blocks = 1 << tx_size;

  // above
  if (has_eob && xd->mb_to_right_edge < 0) {
    int i;
    const int blocks_wide = pd->n4_w +
                            (xd->mb_to_right_edge >> (5 + pd->subsampling_x));
    int above_contexts = tx_size_in_blocks;
    if (above_contexts + aoff > blocks_wide)
      above_contexts = blocks_wide - aoff;

    for (i = 0; i < above_contexts; ++i)
      a[i] = has_eob;
    for (i = above_contexts; i < tx_size_in_blocks; ++i)
      a[i] = 0;
  } else {
    memset(a, has_eob, sizeof(ENTROPY_CONTEXT) * tx_size_in_blocks);
  }

  // left
  if (has_eob && xd->mb_to_bottom_edge < 0) {
    int i;
    const int blocks_high = pd->n4_h +
                            (xd->mb_to_bottom_edge >> (5 + pd->subsampling_y));
    int left_contexts = tx_size_in_blocks;
    if (left_contexts + loff > blocks_high)
      left_contexts = blocks_high - loff;

    for (i = 0; i < left_contexts; ++i)
      l[i] = has_eob;
    for (i = left_contexts; i < tx_size_in_blocks; ++i)
      l[i] = 0;
  } else {
    memset(l, has_eob, sizeof(ENTROPY_CONTEXT) * tx_size_in_blocks);
  }
}

int vp9_decode_block_tokens(MACROBLOCKD *xd,
                            int plane, const scan_order *sc,
                            int x, int y,
                            TX_SIZE tx_size, vpx_reader *r,
                            int seg_id) {
  struct macroblockd_plane *const pd = &xd->plane[plane];
  const int16_t *const dequant = pd->seg_dequant[seg_id];
  const int ctx = get_entropy_context(tx_size, pd->above_context + x,
                                               pd->left_context + y);
  const int eob = decode_coefs(xd, get_plane_type(plane),
                               pd->dqcoeff, tx_size,
                               dequant, ctx, sc->scan, sc->neighbors, r);
  dec_set_contexts(xd, pd, tx_size, eob > 0, x, y);
  return eob;
}