make buid_inter_predictors block size agnostic (luma)

This commit converts the luma versions of vp9_build_inter_predictors_sb
to use a common function. Update the convolution functions to support
block sizes larger than 16x16, and add a foreach_predicted_block walker.

Next step will be to calculate the UV motion vector and implement SBUV,
then fold in vp9_build_inter16x16_predictors_mb and SPLITMV.

At the 16x16, 32x32, and 64x64 levels implemented in this commit, each
plane is predicted with only a single call to vp9_build_inter_predictor.
This is not yet called for SPLITMV. If the notion of SPLITMV/I8X8/I4X4
goes away, then the prediction block walker can go away, since we'll
always predict the whole bsize in a single step. Implemented using a
block walker at this stage for SPLITMV, as a 4x4 "prediction block size"
within the BLOCK_SIZE_MB16X16 macroblock. It would also support other
rectangular sizes too, if the blocks smaller than 16x16 remain
implemented as a SPLITMV-like thing. Just using 4x4 for now.

There's also a potential to combine with the foreach_transformed_block
walker if the logic for calculating the size of the subsampled
transform is made more straightforward, perhaps as a consequence of
supporing smaller macroblocks than 16x16. Will watch what happens there.

Change-Id: Iddd9973398542216601b630c628b9b7fdee33fe2

3 files changed, 144 insertions, 107 deletions

diff --git a/vp9/common/vp9_blockd.h b/vp9/common/vp9_blockd.h
index 7eb9f8e86..dd957618c 100644
--- a/vp9/common/vp9_blockd.h
+++ b/vp9/common/vp9_blockd.h
@@ -875,4 +875,62 @@ static INLINE void foreach_transformed_block_uv(
   }
 }
 
+// TODO(jkoleszar): In principle, pred_w, pred_h are unnecessary, as we could
+// calculate the subsampled BLOCK_SIZE_TYPE, but that type isn't defined for
+// sizes smaller than 16x16 yet.
+typedef void (*foreach_predicted_block_visitor)(int plane, int block,
+                                                BLOCK_SIZE_TYPE bsize,
+                                                int pred_w, int pred_h,
+                                                void *arg);
+static INLINE void foreach_predicted_block_in_plane(
+    const MACROBLOCKD* const xd, BLOCK_SIZE_TYPE bsize, int plane,
+    foreach_predicted_block_visitor visit, void *arg) {
+  const int bw = b_width_log2(bsize), bh = b_height_log2(bsize);
+
+  // block sizes in number of 4x4 blocks log 2 ("*_b")
+  // 4x4=0, 8x8=2, 16x16=4, 32x32=6, 64x64=8
+  const MB_PREDICTION_MODE mode = xd->mode_info_context->mbmi.mode;
+  const int block_size_b = bw + bh;
+
+  // subsampled size of the block
+  const int ss_sum = xd->plane[plane].subsampling_x +
+                     xd->plane[plane].subsampling_y;
+  const int ss_block_size = block_size_b - ss_sum;
+
+  // size of the predictor to use.
+  // TODO(jkoleszar): support I8X8, I4X4
+  const int pred_w = bw - xd->plane[plane].subsampling_x;
+  const int pred_h = bh - xd->plane[plane].subsampling_y;
+  const int pred_b = mode == SPLITMV ? 0 : pred_w + pred_h;
+  const int step = 1 << pred_b;
+
+  int i;
+
+  assert(pred_b <= block_size_b);
+  assert(pred_b == ss_block_size);
+  for (i = 0; i < (1 << ss_block_size); i += step) {
+    visit(plane, i, bsize, pred_w, pred_h, arg);
+  }
+}
+static INLINE void foreach_predicted_block(
+    const MACROBLOCKD* const xd, BLOCK_SIZE_TYPE bsize,
+    foreach_predicted_block_visitor visit, void *arg) {
+  int plane;
+
+  for (plane = 0; plane < MAX_MB_PLANE; plane++) {
+    foreach_predicted_block_in_plane(xd, bsize, plane, visit, arg);
+  }
+}
+static INLINE void foreach_predicted_block_uv(
+    const MACROBLOCKD* const xd, BLOCK_SIZE_TYPE bsize,
+    foreach_predicted_block_visitor visit, void *arg) {
+  int plane;
+
+  for (plane = 1; plane < MAX_MB_PLANE; plane++) {
+    foreach_predicted_block_in_plane(xd, bsize, plane, visit, arg);
+  }
+}
+
+
+
 #endif  // VP9_COMMON_VP9_BLOCKD_H_
diff --git a/vp9/common/vp9_reconinter.c b/vp9/common/vp9_reconinter.c
index 71be77df1..002e6eb05 100644
--- a/vp9/common/vp9_reconinter.c
+++ b/vp9/common/vp9_reconinter.c
@@ -527,6 +527,92 @@ static void clamp_uvmv_to_umv_border(MV *mv, const MACROBLOCKD *xd) {
             (xd->mb_to_bottom_edge + (16 << 3)) >> 1 : mv->row;
 }
 
+#if !CONFIG_IMPLICIT_COMPOUNDINTER_WEIGHT
+// TODO(jkoleszar): yet another mv clamping function :-(
+MV clamp_mv_to_umv_border_sb(const MV *src_mv,
+    int bwl, int bhl,
+    int mb_to_left_edge, int mb_to_top_edge,
+    int mb_to_right_edge, int mb_to_bottom_edge) {
+  /* 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 epel_left = (VP9_INTERP_EXTEND + (4 << bwl)) << 3;
+  const int epel_right = epel_left - (1 << 3);
+  const int epel_top = (VP9_INTERP_EXTEND + (4 << bhl)) << 3;
+  const int epel_bottom = epel_top - (1 << 3);
+  MV clamped_mv;
+  clamped_mv.col = clamp(src_mv->col,
+                         mb_to_left_edge - epel_left,
+                         mb_to_right_edge + epel_right);
+  clamped_mv.row = clamp(src_mv->row,
+                         mb_to_top_edge - epel_top,
+                         mb_to_bottom_edge + epel_bottom);
+  return clamped_mv;
+}
+
+struct build_inter_predictors_args {
+  MACROBLOCKD *xd;
+  uint8_t* dst[MAX_MB_PLANE];
+  int dst_stride[MAX_MB_PLANE];
+  int x;
+  int y;
+};
+static void build_inter_predictors(int plane, int block,
+                                   BLOCK_SIZE_TYPE bsize,
+                                   int pred_w, int pred_h,
+                                   void *argv) {
+  const struct build_inter_predictors_args* const arg = argv;
+  const int bwl = pred_w, bw = 4 << bwl;
+  const int bhl = pred_h, bh = 4 << bhl;
+  const int x_idx = block & ((1 << bwl) - 1), y_idx = block >> bwl;
+  const int x = x_idx * 4, y = y_idx * 4;
+  MACROBLOCKD * const xd = arg->xd;
+  const int use_second_ref = xd->mode_info_context->mbmi.second_ref_frame > 0;
+  int which_mv;
+
+  for (which_mv = 0; which_mv < 1 + use_second_ref; ++which_mv) {
+    const MV* const mv = (xd->mode_info_context->mbmi.mode == SPLITMV)
+         ? &xd->block[block].bmi.as_mv[which_mv].as_mv
+         : &xd->mode_info_context->mbmi.mv[which_mv].as_mv;
+
+    const uint8_t * const base_pre = which_mv ? xd->second_pre.y_buffer
+                                             : xd->pre.y_buffer;
+    const int pre_stride = which_mv ? xd->second_pre.y_stride
+                                    : xd->pre.y_stride;
+    const uint8_t *const pre = base_pre +
+        scaled_buffer_offset(x, y, pre_stride, &xd->scale_factor[which_mv]);
+    struct scale_factors * const scale =
+      plane == 0 ? &xd->scale_factor[which_mv] : &xd->scale_factor_uv[which_mv];
+
+    int_mv clamped_mv;
+    clamped_mv.as_mv = clamp_mv_to_umv_border_sb(mv, bwl, bhl,
+                                                 xd->mb_to_left_edge,
+                                                 xd->mb_to_top_edge,
+                                                 xd->mb_to_right_edge,
+                                                 xd->mb_to_bottom_edge);
+
+    scale->set_scaled_offsets(scale, arg->y + y, arg->x + x);
+
+    vp9_build_inter_predictor(pre, pre_stride,
+                              arg->dst[plane], arg->dst_stride[plane],
+                              &clamped_mv, &xd->scale_factor[which_mv],
+                              bw, bh, which_mv, &xd->subpix);
+  }
+}
+void vp9_build_inter_predictors_sby(MACROBLOCKD *xd,
+                                    uint8_t *dst_y,
+                                    int dst_ystride,
+                                    int mb_row,
+                                    int mb_col,
+                                    BLOCK_SIZE_TYPE bsize) {
+  struct build_inter_predictors_args args = {
+    xd, {dst_y, NULL, NULL}, {dst_ystride, 0, 0}, mb_col * 16, mb_row * 16
+  };
+  foreach_predicted_block_in_plane(xd, bsize, 0, build_inter_predictors, &args);
+}
+#endif
+
 #define AVERAGE_WEIGHT  (1 << (2 * CONFIG_IMPLICIT_COMPOUNDINTER_WEIGHT))
 
 #if CONFIG_IMPLICIT_COMPOUNDINTER_WEIGHT
@@ -867,49 +953,6 @@ static void build_inter16x16_predictors_mby_w(MACROBLOCKD *xd,
                               which_mv ? weight : 0, &xd->subpix);
   }
 }
-
-void vp9_build_inter16x16_predictors_mby(MACROBLOCKD *xd,
-                                         uint8_t *dst_y,
-                                         int dst_ystride,
-                                         int mb_row,
-                                         int mb_col) {
-  int weight = get_implicit_compoundinter_weight(xd, mb_row, mb_col);
-
-  build_inter16x16_predictors_mby_w(xd, dst_y, dst_ystride, weight,
-                                    mb_row, mb_col);
-}
-
-#else
-
-void vp9_build_inter16x16_predictors_mby(MACROBLOCKD *xd,
-                                         uint8_t *dst_y,
-                                         int dst_ystride,
-                                         int mb_row,
-                                         int mb_col) {
-  const int use_second_ref = xd->mode_info_context->mbmi.second_ref_frame > 0;
-  int which_mv;
-
-  for (which_mv = 0; which_mv < 1 + use_second_ref; ++which_mv) {
-    const int clamp_mvs = which_mv ?
-         xd->mode_info_context->mbmi.need_to_clamp_secondmv :
-         xd->mode_info_context->mbmi.need_to_clamp_mvs;
-
-    uint8_t *base_pre = which_mv ? xd->second_pre.y_buffer : xd->pre.y_buffer;
-    int pre_stride = which_mv ? xd->second_pre.y_stride : xd->pre.y_stride;
-    int_mv ymv;
-    struct scale_factors *scale = &xd->scale_factor[which_mv];
-
-    ymv.as_int = xd->mode_info_context->mbmi.mv[which_mv].as_int;
-
-    if (clamp_mvs)
-      clamp_mv_to_umv_border(&ymv.as_mv, xd);
-
-    scale->set_scaled_offsets(scale, mb_row * 16, mb_col * 16);
-
-    vp9_build_inter_predictor(base_pre, pre_stride, dst_y, dst_ystride,
-                              &ymv, scale, 16, 16, which_mv, &xd->subpix);
-  }
-}
 #endif
 
 #if CONFIG_IMPLICIT_COMPOUNDINTER_WEIGHT
@@ -1109,64 +1152,6 @@ void vp9_build_inter_predictors_sby(MACROBLOCKD *x,
   build_inter_predictors_sby_w(x, dst_y, dst_ystride, weight,
                                     mb_row, mb_col, bsize);
 }
-
-#else
-
-// TODO(jingning): vp9_convolve8_ssse3_ limits the dimension up to 16. Currently
-// handle inter prediction of block sizes above 16x16 separately from those
-// smaller ones. Need to combine them all in to a unified inter prediction
-// function.
-void vp9_build_inter_predictors_sby(MACROBLOCKD *x,
-                                    uint8_t *dst_y,
-                                    int dst_ystride,
-                                    int mb_row,
-                                    int mb_col,
-                                    BLOCK_SIZE_TYPE bsize) {
-  const int bwl = mb_width_log2(bsize),  bw = 1 << bwl;
-  const int bhl = mb_height_log2(bsize), bh = 1 << bhl;
-  uint8_t *y1 = x->pre.y_buffer;
-  uint8_t *y2 = x->second_pre.y_buffer;
-  int edge[4], n;
-
-  edge[0] = x->mb_to_top_edge;
-  edge[1] = x->mb_to_bottom_edge;
-  edge[2] = x->mb_to_left_edge;
-  edge[3] = x->mb_to_right_edge;
-
-  for (n = 0; n < bw * bh; n++) {
-    const int x_idx = n & (bw - 1), y_idx = n >> bwl;
-
-    x->mb_to_top_edge    = edge[0] -           ((y_idx  * 16) << 3);
-    x->mb_to_bottom_edge = edge[1] + (((bh - 1 - y_idx) * 16) << 3);
-    x->mb_to_left_edge   = edge[2] -           ((x_idx  * 16) << 3);
-    x->mb_to_right_edge  = edge[3] + (((bw - 1 - x_idx) * 16) << 3);
-
-    x->pre.y_buffer = y1 + scaled_buffer_offset(x_idx * 16,
-                                                y_idx * 16,
-                                                x->pre.y_stride,
-                                                &x->scale_factor[0]);
-    if (x->mode_info_context->mbmi.second_ref_frame > 0) {
-      x->second_pre.y_buffer = y2 +
-          scaled_buffer_offset(x_idx * 16,
-                               y_idx * 16,
-                               x->second_pre.y_stride,
-                               &x->scale_factor[1]);
-    }
-    vp9_build_inter16x16_predictors_mby(x,
-        dst_y + y_idx * 16 * dst_ystride  + x_idx * 16,
-        dst_ystride, mb_row + y_idx, mb_col + x_idx);
-  }
-  x->mb_to_top_edge    = edge[0];
-  x->mb_to_bottom_edge = edge[1];
-  x->mb_to_left_edge   = edge[2];
-  x->mb_to_right_edge  = edge[3];
-
-  x->pre.y_buffer = y1;
-  if (x->mode_info_context->mbmi.second_ref_frame > 0) {
-    x->second_pre.y_buffer = y2;
-  }
-}
-
 #endif
 
 #if CONFIG_IMPLICIT_COMPOUNDINTER_WEIGHT
diff --git a/vp9/common/vp9_reconinter.h b/vp9/common/vp9_reconinter.h
index 533d30466..77fa9ab3f 100644
--- a/vp9/common/vp9_reconinter.h
+++ b/vp9/common/vp9_reconinter.h
@@ -16,12 +16,6 @@
 
 struct subpix_fn_table;
 
-void vp9_build_inter16x16_predictors_mby(MACROBLOCKD *xd,
-                                         uint8_t *dst_y,
-                                         int dst_ystride,
-                                         int mb_row,
-                                         int mb_col);
-
 void vp9_build_inter16x16_predictors_mbuv(MACROBLOCKD *xd,
                                           uint8_t *dst_u,
                                           uint8_t *dst_v,