vpx/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_bool(vpx_reader *r, int prob, BD_VALUE *value,
                            int *count, unsigned int *range) {
  const unsigned int split = (*range * prob + (256 - prob)) >> CHAR_BIT;
  const BD_VALUE bigsplit = (BD_VALUE)split << (BD_VALUE_SIZE - CHAR_BIT);

  if (*count < 0) {
    r->value = *value;
    r->count = *count;
    vpx_reader_fill(r);
    *value = r->value;
    *count = r->count;
  }

  if (*value >= bigsplit) {
    *range = *range - split;
    *value = *value - bigsplit;
    {
      const int shift = vpx_norm[*range];
      *range <<= shift;
      *value <<= shift;
      *count -= shift;
    }
    return 1;
  }
  *range = split;
  {
    const int shift = vpx_norm[*range];
    *range <<= shift;
    *value <<= shift;
    *count -= shift;
  }
  return 0;
}

static INLINE int read_coeff(vpx_reader *r, const vpx_prob *probs, int n,
                             BD_VALUE *value, int *count, unsigned int *range) {
  int i, val = 0;
  for (i = 0; i < n; ++i)
    val = (val << 1) | read_bool(r, probs[i], value, count, range);
  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;
  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;
  // Keep value, range, and count as locals.  The compiler produces better
  // results with the locals than using r directly.
  BD_VALUE value = r->value;
  unsigned int range = r->range;
  int count = r->count;

  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 (!read_bool(r, prob[EOB_CONTEXT_NODE], &value, &count, &range)) {
      INCREMENT_COUNT(EOB_MODEL_TOKEN);
      break;
    }

    while (!read_bool(r, prob[ZERO_CONTEXT_NODE], &value, &count, &range)) {
      INCREMENT_COUNT(ZERO_TOKEN);
      dqv = dq[1];
      token_cache[scan[c]] = 0;
      ++c;
      if (c >= max_eob) {
        r->value = value;
        r->range = range;
        r->count = count;
        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 (read_bool(r, prob[ONE_CONTEXT_NODE], &value, &count, &range)) {
      const vpx_prob *p = vp9_pareto8_full[prob[PIVOT_NODE] - 1];
      INCREMENT_COUNT(TWO_TOKEN);
      if (read_bool(r, p[0], &value, &count, &range)) {
        if (read_bool(r, p[3], &value, &count, &range)) {
          token_cache[scan[c]] = 5;
          if (read_bool(r, p[5], &value, &count, &range)) {
            if (read_bool(r, p[7], &value, &count, &range)) {
              val = CAT6_MIN_VAL +
                    read_coeff(r, cat6_prob, cat6_bits, &value, &count, &range);
            } else {
              val = CAT5_MIN_VAL +
                    read_coeff(r, vp9_cat5_prob, 5, &value, &count, &range);
            }
          } else if (read_bool(r, p[6], &value, &count, &range)) {
            val = CAT4_MIN_VAL +
                  read_coeff(r, vp9_cat4_prob, 4, &value, &count, &range);
          } else {
            val = CAT3_MIN_VAL +
                  read_coeff(r, vp9_cat3_prob, 3, &value, &count, &range);
          }
        } else {
          token_cache[scan[c]] = 4;
          if (read_bool(r, p[4], &value, &count, &range)) {
            val = CAT2_MIN_VAL +
                  read_coeff(r, vp9_cat2_prob, 2, &value, &count, &range);
          } else {
            val = CAT1_MIN_VAL +
                  read_coeff(r, vp9_cat1_prob, 1, &value, &count, &range);
          }
        }
#if CONFIG_VP9_HIGHBITDEPTH
        // val may use 18-bits
        v = (int)(((int64_t)val * dqv) >> dq_shift);
#else
        v = (val * dqv) >> dq_shift;
#endif
      } else {
        if (read_bool(r, p[1], &value, &count, &range)) {
          token_cache[scan[c]] = 3;
          v = ((3 + read_bool(r, p[2], &value, &count, &range)) * dqv) >>
              dq_shift;
        } else {
          token_cache[scan[c]] = 2;
          v = (2 * dqv) >> dq_shift;
        }
      }
    } else {
      INCREMENT_COUNT(ONE_TOKEN);
      token_cache[scan[c]] = 1;
      v = dqv >> dq_shift;
    }
#if CONFIG_COEFFICIENT_RANGE_CHECKING
#if CONFIG_VP9_HIGHBITDEPTH
    dqcoeff[scan[c]] = highbd_check_range(
        read_bool(r, 128, &value, &count, &range) ? -v : v, xd->bd);
#else
    dqcoeff[scan[c]] =
        check_range(read_bool(r, 128, &value, &count, &range) ? -v : v);
#endif  // CONFIG_VP9_HIGHBITDEPTH
#else
    if (read_bool(r, 128, &value, &count, &range)) {
      dqcoeff[scan[c]] = -v;
    } else {
      dqcoeff[scan[c]] = v;
    }
#endif  // CONFIG_COEFFICIENT_RANGE_CHECKING
    ++c;
    ctx = get_coef_context(nb, token_cache, c);
    dqv = dq[1];
  }

  r->value = value;
  r->range = range;
  r->count = count;
  return c;
}

static void get_ctx_shift(MACROBLOCKD *xd, int *ctx_shift_a, int *ctx_shift_l,
                          int x, int y, unsigned int tx_size_in_blocks) {
  if (xd->max_blocks_wide) {
    if (tx_size_in_blocks + x > xd->max_blocks_wide)
      *ctx_shift_a = (tx_size_in_blocks - (xd->max_blocks_wide - x)) * 8;
  }
  if (xd->max_blocks_high) {
    if (tx_size_in_blocks + y > xd->max_blocks_high)
      *ctx_shift_l = (tx_size_in_blocks - (xd->max_blocks_high - y)) * 8;
  }
}

int vp9_decode_block_tokens(TileWorkerData *twd, int plane,
                            const scan_order *sc, int x, int y, TX_SIZE tx_size,
                            int seg_id) {
  vpx_reader *r = &twd->bit_reader;
  MACROBLOCKD *xd = &twd->xd;
  struct macroblockd_plane *const pd = &xd->plane[plane];
  const int16_t *const dequant = pd->seg_dequant[seg_id];
  int eob;
  ENTROPY_CONTEXT *a = pd->above_context + x;
  ENTROPY_CONTEXT *l = pd->left_context + y;
  int ctx;
  int ctx_shift_a = 0;
  int ctx_shift_l = 0;

  switch (tx_size) {
    case TX_4X4:
      ctx = a[0] != 0;
      ctx += l[0] != 0;
      eob = decode_coefs(xd, get_plane_type(plane), pd->dqcoeff, tx_size,
                         dequant, ctx, sc->scan, sc->neighbors, r);
      a[0] = l[0] = (eob > 0);
      break;
    case TX_8X8:
      get_ctx_shift(xd, &ctx_shift_a, &ctx_shift_l, x, y, 1 << TX_8X8);
      ctx = !!*(const uint16_t *)a;
      ctx += !!*(const uint16_t *)l;
      eob = decode_coefs(xd, get_plane_type(plane), pd->dqcoeff, tx_size,
                         dequant, ctx, sc->scan, sc->neighbors, r);
      *(uint16_t *)a = ((eob > 0) * 0x0101) >> ctx_shift_a;
      *(uint16_t *)l = ((eob > 0) * 0x0101) >> ctx_shift_l;
      break;
    case TX_16X16:
      get_ctx_shift(xd, &ctx_shift_a, &ctx_shift_l, x, y, 1 << TX_16X16);
      ctx = !!*(const uint32_t *)a;
      ctx += !!*(const uint32_t *)l;
      eob = decode_coefs(xd, get_plane_type(plane), pd->dqcoeff, tx_size,
                         dequant, ctx, sc->scan, sc->neighbors, r);
      *(uint32_t *)a = ((eob > 0) * 0x01010101) >> ctx_shift_a;
      *(uint32_t *)l = ((eob > 0) * 0x01010101) >> ctx_shift_l;
      break;
    case TX_32X32:
      get_ctx_shift(xd, &ctx_shift_a, &ctx_shift_l, x, y, 1 << TX_32X32);
      // NOTE: casting to uint64_t here is safe because the default memory
      // alignment is at least 8 bytes and the TX_32X32 is aligned on 8 byte
      // boundaries.
      ctx = !!*(const uint64_t *)a;
      ctx += !!*(const uint64_t *)l;
      eob = decode_coefs(xd, get_plane_type(plane), pd->dqcoeff, tx_size,
                         dequant, ctx, sc->scan, sc->neighbors, r);
      *(uint64_t *)a = ((eob > 0) * 0x0101010101010101ULL) >> ctx_shift_a;
      *(uint64_t *)l = ((eob > 0) * 0x0101010101010101ULL) >> ctx_shift_l;
      break;
    default:
      assert(0 && "Invalid transform size.");
      eob = 0;
      break;
  }

  return eob;
}