vp9_quantize.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 <math.h>
#include "vpx_mem/vpx_mem.h"

#include "vp9/encoder/vp9_onyx_int.h"
#include "vp9/encoder/vp9_quantize.h"
#include "vp9/common/vp9_quant_common.h"

#include "vp9/common/vp9_seg_common.h"

#ifdef ENC_DEBUG
extern int enc_debug;
#endif

static INLINE int plane_idx(int plane) {
  return plane == 0 ? 0 :
         plane == 1 ? 16 : 20;
}

static void quantize(int16_t *zbin_boost_orig_ptr,
                     int16_t *coeff_ptr, int n_coeffs, int skip_block,
                     int16_t *zbin_ptr, int16_t *round_ptr, int16_t *quant_ptr,
                     uint8_t *quant_shift_ptr,
                     int16_t *qcoeff_ptr, int16_t *dqcoeff_ptr,
                     int16_t *dequant_ptr, int zbin_oq_value,
                     uint16_t *eob_ptr,
                     const int *scan, int mul) {
  int i, rc, eob;
  int zbin;
  int x, y, z, sz;
  int zero_run = 0;
  int16_t *zbin_boost_ptr = zbin_boost_orig_ptr;

  vpx_memset(qcoeff_ptr, 0, n_coeffs*sizeof(int16_t));
  vpx_memset(dqcoeff_ptr, 0, n_coeffs*sizeof(int16_t));

  eob = -1;

  if (!skip_block) {
    for (i = 0; i < n_coeffs; i++) {
      rc   = scan[i];
      z    = coeff_ptr[rc] * mul;

      zbin = (zbin_ptr[rc != 0] + zbin_boost_ptr[zero_run] + zbin_oq_value);
      zero_run += (zero_run < 15);

      sz = (z >> 31);                               // sign of z
      x  = (z ^ sz) - sz;                           // x = abs(z)

      if (x >= zbin) {
        x += (round_ptr[rc != 0]);
        y  = ((int)(((int)(x * quant_ptr[rc != 0]) >> 16) + x))
            >> quant_shift_ptr[rc != 0];            // quantize (x)
        x  = (y ^ sz) - sz;                         // get the sign back
        qcoeff_ptr[rc]  = x;                        // write to destination
        dqcoeff_ptr[rc] = x * dequant_ptr[rc != 0] / mul;  // dequantized value

        if (y) {
          eob = i;                                  // last nonzero coeffs
          zero_run = 0;
        }