vpx/vp9/common/vp9_reconinter.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 <assert.h>

#include "./vpx_scale_rtcd.h"
#include "./vpx_config.h"

#include "vpx/vpx_integer.h"

#include "vp9/common/vp9_blockd.h"
#include "vp9/common/vp9_filter.h"
#include "vp9/common/vp9_reconinter.h"
#include "vp9/common/vp9_reconintra.h"


static void inter_predictor(const uint8_t *src, int src_stride,
                            uint8_t *dst, int dst_stride,
                            const MV32 *mv,
                            const struct scale_factors *scale,
                            int w, int h, int ref,
                            const struct subpix_fn_table *subpix,
                            int xs, int ys) {
  const int subpel_x = mv->col & SUBPEL_MASK;
  const int subpel_y = mv->row & SUBPEL_MASK;

  src += (mv->row >> SUBPEL_BITS) * src_stride + (mv->col >> SUBPEL_BITS);
  scale->sfc->predict[subpel_x != 0][subpel_y != 0][ref](
      src, src_stride, dst, dst_stride,
      subpix->filter_x[subpel_x], xs,
      subpix->filter_y[subpel_y], ys,
      w, h);
}

void vp9_build_inter_predictor(const uint8_t *src, int src_stride,
                               uint8_t *dst, int dst_stride,
                               const MV *src_mv,
                               const struct scale_factors *scale,
                               int w, int h, int ref,
                               const struct subpix_fn_table *subpix,
                               enum mv_precision precision) {
  const int is_q4 = precision == MV_PRECISION_Q4;
  const MV mv_q4 = { is_q4 ? src_mv->row : src_mv->row * 2,
                     is_q4 ? src_mv->col : src_mv->col * 2 };
  const struct scale_factors_common *sfc = scale->sfc;
  const MV32 mv = sfc->scale_mv(&mv_q4, scale);

  inter_predictor(src, src_stride, dst, dst_stride, &mv, scale,
                  w, h, ref, subpix, sfc->x_step_q4, sfc->y_step_q4);
}

static INLINE int round_mv_comp_q4(int value) {
  return (value < 0 ? value - 2 : value + 2) / 4;
}

static MV mi_mv_pred_q4(const MODE_INFO *mi, int idx) {
  MV res = { round_mv_comp_q4(mi->bmi[0].as_mv[idx].as_mv.row +
                              mi->bmi[1].as_mv[idx].as_mv.row +
                              mi->bmi[2].as_mv[idx].as_mv.row +
                              mi->bmi[3].as_mv[idx].as_mv.row),
             round_mv_comp_q4(mi->bmi[0].as_mv[idx].as_mv.col +
                              mi->bmi[1].as_mv[idx].as_mv.col +
                              mi->bmi[2].as_mv[idx].as_mv.col +
                              mi->bmi[3].as_mv[idx].as_mv.col) };
  return res;
}

// TODO(jkoleszar): yet another mv clamping function :-(
MV clamp_mv_to_umv_border_sb(const MACROBLOCKD *xd, const MV *src_mv,
                             int bw, int bh, int ss_x, int ss_y) {
  // If the MV points so far into the UMV border that no visible pixels
  // are used for reconstruction, the subpel part of the MV can be
  // discarded and the MV limited to 16 pixels with equivalent results.
  const int spel_left = (VP9_INTERP_EXTEND + bw) << SUBPEL_BITS;
  const int spel_right = spel_left - SUBPEL_SHIFTS;
  const int spel_top = (VP9_INTERP_EXTEND + bh) << SUBPEL_BITS;
  const int spel_bottom = spel_top - SUBPEL_SHIFTS;
  MV clamped_mv = {
    src_mv->row * (1 << (1 - ss_y)),
    src_mv->col * (1 << (1 - ss_x))
  };
  assert(ss_x <= 1);
  assert(ss_y <= 1);

  clamp_mv(&clamped_mv,
           xd->mb_to_left_edge * (1 << (1 - ss_x)) - spel_left,
           xd->mb_to_right_edge * (1 << (1 - ss_x)) + spel_right,
           xd->mb_to_top_edge * (1 << (1 - ss_y)) - spel_top,
           xd->mb_to_bottom_edge * (1 << (1 - ss_y)) + spel_bottom);

  return clamped_mv;
}


// TODO(jkoleszar): In principle, pred_w, pred_h are unnecessary, as we could
// calculate the subsampled BLOCK_SIZE, but that type isn't defined for
// sizes smaller than 16x16 yet.
static void build_inter_predictors(MACROBLOCKD *xd, int plane, int block,
                                   BLOCK_SIZE bsize, int pred_w, int pred_h,
                                   int mi_x, int mi_y) {
  struct macroblockd_plane *const pd = &xd->plane[plane];
  const int bwl = b_width_log2(bsize) - pd->subsampling_x;
  const int bw = 4 << bwl;
  const int bh = plane_block_height(bsize, pd);
  const int x = 4 * (block & ((1 << bwl) - 1));
  const int y = 4 * (block >> bwl);
  const MODE_INFO *mi = xd->mi_8x8[0];
  const int is_compound = has_second_ref(&mi->mbmi);
  int ref;

  assert(x < bw);
  assert(y < bh);
  assert(mi->mbmi.sb_type < BLOCK_8X8 || 4 << pred_w == bw);
  assert(mi->mbmi.sb_type < BLOCK_8X8 || 4 << pred_h == bh);

  for (ref = 0; ref < 1 + is_compound; ++ref) {
    struct scale_factors *const scale = &xd->scale_factor[ref];
    struct buf_2d *const pre_buf = &pd->pre[ref];
    struct buf_2d *const dst_buf = &pd->dst;
    uint8_t *const dst = dst_buf->buf + dst_buf->stride * y + x;

    // TODO(jkoleszar): All chroma MVs in SPLITMV mode are taken as the
    // same MV (the average of the 4 luma MVs) but we could do something
    // smarter for non-4:2:0. Just punt for now, pending the changes to get
    // rid of SPLITMV mode entirely.
    const MV mv = mi->mbmi.sb_type < BLOCK_8X8
               ? (plane == 0 ? mi->bmi[block].as_mv[ref].as_mv
                             : mi_mv_pred_q4(mi, ref))
               : mi->mbmi.mv[ref].as_mv;

    // TODO(jkoleszar): This clamping is done in the incorrect place for the
    // scaling case. It needs to be done on the scaled MV, not the pre-scaling
    // MV. Note however that it performs the subsampling aware scaling so
    // that the result is always q4.
    // mv_precision precision is MV_PRECISION_Q4.
    const MV mv_q4 = clamp_mv_to_umv_border_sb(xd, &mv, bw, bh,
                                               pd->subsampling_x,
                                               pd->subsampling_y);

    uint8_t *pre;
    MV32 scaled_mv;
    int xs, ys;

    if (vp9_is_scaled(scale->sfc)) {
      pre = pre_buf->buf + scaled_buffer_offset(x, y, pre_buf->stride, scale);
      scale->sfc->set_scaled_offsets(scale, mi_y + y, mi_x + x);
      scaled_mv = scale->sfc->scale_mv(&mv_q4, scale);
      xs = scale->sfc->x_step_q4;
      ys = scale->sfc->y_step_q4;
    } else {
      pre = pre_buf->buf + (y * pre_buf->stride + x);
      scaled_mv.row = mv_q4.row;
      scaled_mv.col = mv_q4.col;
      xs = ys = 16;
    }

    inter_predictor(pre, pre_buf->stride, dst, dst_buf->stride,
                    &scaled_mv, scale,
                    4 << pred_w, 4 << pred_h, ref,
                    &xd->subpix, xs, ys);
  }
}

static void build_inter_predictors_for_planes(MACROBLOCKD *xd, BLOCK_SIZE bsize,
                                              int mi_row, int mi_col,
                                              int plane_from, int plane_to) {
  int plane;
  for (plane = plane_from; plane <= plane_to; ++plane) {
    const int mi_x = mi_col * MI_SIZE;
    const int mi_y = mi_row * MI_SIZE;
    const int bwl = b_width_log2(bsize) - xd->plane[plane].subsampling_x;
    const int bhl = b_height_log2(bsize) - xd->plane[plane].subsampling_y;

    if (xd->mi_8x8[0]->mbmi.sb_type < BLOCK_8X8) {
      int i = 0, x, y;
      assert(bsize == BLOCK_8X8);
      for (y = 0; y < 1 << bhl; ++y)
        for (x = 0; x < 1 << bwl; ++x)
          build_inter_predictors(xd, plane, i++, bsize, 0, 0, mi_x, mi_y);
    } else {
      build_inter_predictors(xd, plane, 0, bsize, bwl, bhl, mi_x, mi_y);
    }
  }
}

void vp9_build_inter_predictors_sby(MACROBLOCKD *xd, int mi_row, int mi_col,
                                    BLOCK_SIZE bsize) {
  build_inter_predictors_for_planes(xd, bsize, mi_row, mi_col, 0, 0);
}
void vp9_build_inter_predictors_sbuv(MACROBLOCKD *xd, int mi_row, int mi_col,
                                     BLOCK_SIZE bsize) {
  build_inter_predictors_for_planes(xd, bsize, mi_row, mi_col, 1,
                                    MAX_MB_PLANE - 1);
}
void vp9_build_inter_predictors_sb(MACROBLOCKD *xd, int mi_row, int mi_col,
                                   BLOCK_SIZE bsize) {
  build_inter_predictors_for_planes(xd, bsize, mi_row, mi_col, 0,
                                    MAX_MB_PLANE - 1);
}

// TODO(dkovalev: find better place for this function)
void vp9_setup_scale_factors(VP9_COMMON *cm, int i) {
  const int ref = cm->active_ref_idx[i];
  struct scale_factors *const sf = &cm->active_ref_scale[i];
  struct scale_factors_common *const sfc = &cm->active_ref_scale_comm[i];
  if (ref >= NUM_YV12_BUFFERS) {
    vp9_zero(*sf);
    vp9_zero(*sfc);
  } else {
    YV12_BUFFER_CONFIG *const fb = &cm->yv12_fb[ref];
    vp9_setup_scale_factors_for_frame(sf, sfc,
                                      fb->y_crop_width, fb->y_crop_height,
                                      cm->width, cm->height);

    if (vp9_is_scaled(sfc))
      vp9_extend_frame_borders(fb, cm->subsampling_x, cm->subsampling_y);
  }
}