src/third_party/libvpx/vp9/encoder/vp9_aq_variance.c

/*
 *  Copyright (c) 2013 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_ports/mem.h"
#include "vpx_ports/system_state.h"

#include "vp9/encoder/vp9_aq_variance.h"

#include "vp9/common/vp9_seg_common.h"

#include "vp9/encoder/vp9_ratectrl.h"
#include "vp9/encoder/vp9_rd.h"
#include "vp9/encoder/vp9_encodeframe.h"
#include "vp9/encoder/vp9_segmentation.h"

#define ENERGY_MIN (-4)
#define ENERGY_MAX (1)
#define ENERGY_SPAN (ENERGY_MAX - ENERGY_MIN + 1)
#define ENERGY_IN_BOUNDS(energy) \
  assert((energy) >= ENERGY_MIN && (energy) <= ENERGY_MAX)

static const double rate_ratio[MAX_SEGMENTS] = { 2.5,  2.0, 1.5, 1.0,
                                                 0.75, 1.0, 1.0, 1.0 };
static const int segment_id[ENERGY_SPAN] = { 0, 1, 1, 2, 3, 4 };

#define SEGMENT_ID(i) segment_id[(i)-ENERGY_MIN]

DECLARE_ALIGNED(16, static const uint8_t, vp9_64_zeros[64]) = { 0 };
#if CONFIG_VP9_HIGHBITDEPTH
DECLARE_ALIGNED(16, static const uint16_t, vp9_highbd_64_zeros[64]) = { 0 };
#endif

unsigned int vp9_vaq_segment_id(int energy) {
  ENERGY_IN_BOUNDS(energy);
  return SEGMENT_ID(energy);
}

void vp9_vaq_frame_setup(VP9_COMP *cpi) {
  VP9_COMMON *cm = &cpi->common;
  struct segmentation *seg = &cm->seg;
  int i;

  if (frame_is_intra_only(cm) || cm->error_resilient_mode ||
      cpi->refresh_alt_ref_frame || cpi->force_update_segmentation ||
      (cpi->refresh_golden_frame && !cpi->rc.is_src_frame_alt_ref)) {
    vp9_enable_segmentation(seg);
    vp9_clearall_segfeatures(seg);

    seg->abs_delta = SEGMENT_DELTADATA;

    vpx_clear_system_state();

    for (i = 0; i < MAX_SEGMENTS; ++i) {
      int qindex_delta =
          vp9_compute_qdelta_by_rate(&cpi->rc, cm->frame_type, cm->base_qindex,
                                     rate_ratio[i], cm->bit_depth);

      // We don't allow qindex 0 in a segment if the base value is not 0.
      // Q index 0 (lossless) implies 4x4 encoding only and in AQ mode a segment
      // Q delta is sometimes applied without going back around the rd loop.
      // This could lead to an illegal combination of partition size and q.
      if ((cm->base_qindex != 0) && ((cm->base_qindex + qindex_delta) == 0)) {
        qindex_delta = -cm->base_qindex + 1;
      }

      // No need to enable SEG_LVL_ALT_Q for this segment.
      if (rate_ratio[i] == 1.0) {
        continue;
      }

      vp9_set_segdata(seg, i, SEG_LVL_ALT_Q, qindex_delta);
      vp9_enable_segfeature(seg, i, SEG_LVL_ALT_Q);
    }
  }
}

/* TODO(agrange, paulwilkins): The block_variance calls the unoptimized versions
 * of variance() and highbd_8_variance(). It should not.
 */
static void aq_variance(const uint8_t *a, int a_stride, const uint8_t *b,
                        int b_stride, int w, int h, unsigned int *sse,
                        int *sum) {
  int i, j;

  *sum = 0;
  *sse = 0;

  for (i = 0; i < h; i++) {
    for (j = 0; j < w; j++) {
      const int diff = a[j] - b[j];
      *sum += diff;
      *sse += diff * diff;
    }

    a += a_stride;
    b += b_stride;
  }
}

#if CONFIG_VP9_HIGHBITDEPTH
static void aq_highbd_variance64(const uint8_t *a8, int a_stride,
                                 const uint8_t *b8, int b_stride, int w, int h,
                                 uint64_t *sse, int64_t *sum) {
  int i, j;

  uint16_t *a = CONVERT_TO_SHORTPTR(a8);
  uint16_t *b = CONVERT_TO_SHORTPTR(b8);
  *sum = 0;
  *sse = 0;

  for (i = 0; i < h; i++) {
    for (j = 0; j < w; j++) {
      const int diff = a[j] - b[j];
      *sum += diff;
      *sse += diff * diff;
    }
    a += a_stride;
    b += b_stride;
  }
}

#endif  // CONFIG_VP9_HIGHBITDEPTH

static unsigned int block_variance(VP9_COMP *cpi, MACROBLOCK *x,
                                   BLOCK_SIZE bs) {
  MACROBLOCKD *xd = &x->e_mbd;
  unsigned int var, sse;
  int right_overflow =
      (xd->mb_to_right_edge < 0) ? ((-xd->mb_to_right_edge) >> 3) : 0;
  int bottom_overflow =
      (xd->mb_to_bottom_edge < 0) ? ((-xd->mb_to_bottom_edge) >> 3) : 0;

  if (right_overflow || bottom_overflow) {
    const int bw = 8 * num_8x8_blocks_wide_lookup[bs] - right_overflow;
    const int bh = 8 * num_8x8_blocks_high_lookup[bs] - bottom_overflow;
    int avg;
#if CONFIG_VP9_HIGHBITDEPTH
    if (xd->cur_buf->flags & YV12_FLAG_HIGHBITDEPTH) {
      uint64_t sse64 = 0;
      int64_t sum64 = 0;
      aq_highbd_variance64(x->plane[0].src.buf, x->plane[0].src.stride,
                           CONVERT_TO_BYTEPTR(vp9_highbd_64_zeros), 0, bw, bh,
                           &sse64, &sum64);
      sse = (unsigned int)(sse64 >> (2 * (xd->bd - 8)));
      avg = (int)(sum64 >> (xd->bd - 8));
    } else {
      aq_variance(x->plane[0].src.buf, x->plane[0].src.stride, vp9_64_zeros, 0,
                  bw, bh, &sse, &avg);
    }
#else
    aq_variance(x->plane[0].src.buf, x->plane[0].src.stride, vp9_64_zeros, 0,
                bw, bh, &sse, &avg);
#endif  // CONFIG_VP9_HIGHBITDEPTH
    var = sse - (unsigned int)(((int64_t)avg * avg) / (bw * bh));
    return (unsigned int)(((uint64_t)256 * var) / (bw * bh));
  } else {
#if CONFIG_VP9_HIGHBITDEPTH
    if (xd->cur_buf->flags & YV12_FLAG_HIGHBITDEPTH) {
      var =
          cpi->fn_ptr[bs].vf(x->plane[0].src.buf, x->plane[0].src.stride,
                             CONVERT_TO_BYTEPTR(vp9_highbd_64_zeros), 0, &sse);
    } else {
      var = cpi->fn_ptr[bs].vf(x->plane[0].src.buf, x->plane[0].src.stride,
                               vp9_64_zeros, 0, &sse);
    }
#else
    var = cpi->fn_ptr[bs].vf(x->plane[0].src.buf, x->plane[0].src.stride,
                             vp9_64_zeros, 0, &sse);
#endif  // CONFIG_VP9_HIGHBITDEPTH
    return (unsigned int)(((uint64_t)256 * var) >> num_pels_log2_lookup[bs]);
  }
}

double vp9_log_block_var(VP9_COMP *cpi, MACROBLOCK *x, BLOCK_SIZE bs) {
  unsigned int var = block_variance(cpi, x, bs);
  vpx_clear_system_state();
  return log(var + 1.0);
}

#define DEFAULT_E_MIDPOINT 10.0
static int scale_block_energy(VP9_COMP *cpi, unsigned int block_var) {
  double energy;
  double energy_midpoint;
  energy_midpoint =
      (cpi->oxcf.pass == 2) ? cpi->twopass.mb_av_energy : DEFAULT_E_MIDPOINT;
  energy = log(block_var + 1.0) - energy_midpoint;
  return clamp((int)round(energy), ENERGY_MIN, ENERGY_MAX);
}
#undef DEFAULT_E_MIDPOINT

// Get the range of sub block energy values;
void vp9_get_sub_block_energy(VP9_COMP *cpi, MACROBLOCK *mb, int mi_row,
                              int mi_col, BLOCK_SIZE bsize, int *min_e,
                              int *max_e) {
  VP9_COMMON *const cm = &cpi->common;
  const int bw = num_8x8_blocks_wide_lookup[bsize];
  const int bh = num_8x8_blocks_high_lookup[bsize];
  const int xmis = VPXMIN(cm->mi_cols - mi_col, bw);
  const int ymis = VPXMIN(cm->mi_rows - mi_row, bh);
  int x, y;

  if (xmis < bw || ymis < bh) {
    vp9_setup_src_planes(mb, cpi->Source, mi_row, mi_col);
    *min_e = vp9_block_energy(cpi, mb, bsize);
    *max_e = *min_e;
  } else {
    unsigned int var;
    // Because scale_block_energy is non-decreasing, we can find the min/max
    // block variance and scale afterwards. This avoids a costly scaling at
    // every iteration.
    unsigned int min_var = UINT_MAX;
    unsigned int max_var = 0;

    for (y = 0; y < ymis; ++y) {
      for (x = 0; x < xmis; ++x) {
        vp9_setup_src_planes(mb, cpi->Source, mi_row + y, mi_col + x);
        vpx_clear_system_state();
        var = block_variance(cpi, mb, BLOCK_8X8);
        vpx_clear_system_state();
        min_var = VPXMIN(min_var, var);
        max_var = VPXMAX(max_var, var);
      }
    }
    *min_e = scale_block_energy(cpi, min_var);
    *max_e = scale_block_energy(cpi, max_var);
  }

  // Re-instate source pointers back to what they should have been on entry.
  vp9_setup_src_planes(mb, cpi->Source, mi_row, mi_col);
}

int vp9_block_energy(VP9_COMP *cpi, MACROBLOCK *x, BLOCK_SIZE bs) {
  unsigned int var;
  vpx_clear_system_state();
  var = block_variance(cpi, x, bs);
  vpx_clear_system_state();
  return scale_block_energy(cpi, var);
}