libvpx: Pull from upstream

source/libvpx/vp9/common/vp9_mvref_common.c

Index: source/libvpx/vp9/common/vp9_mvref_common.c
===================================================================
--- source/libvpx/vp9/common/vp9_mvref_common.c	(revision 177019)
+++ source/libvpx/vp9/common/vp9_mvref_common.c	(working copy)
@@ -17,14 +17,13 @@
 };
 static int mb_ref_distance_weight[MVREF_NEIGHBOURS] =
   { 3, 3, 2, 1, 1, 1, 1, 1 };
-#if CONFIG_SUPERBLOCKS
 static int sb_mv_ref_search[MVREF_NEIGHBOURS][2] = {
     {0, -1}, {-1, 0}, {1, -1}, {-1, 1},
     {-1, -1}, {0, -2}, {-2, 0}, {-1, -2}
 };
 static int sb_ref_distance_weight[MVREF_NEIGHBOURS] =
   { 3, 3, 2, 2, 2, 1, 1, 1 };
-#endif
+
 // clamp_mv
 #define MV_BORDER (16 << 3) // Allow 16 pels in 1/8th pel units
 static void clamp_mv(const MACROBLOCKD *xd, int_mv *mv) {
@@ -40,10 +39,29 @@
     mv->as_mv.row = xd->mb_to_bottom_edge + MV_BORDER;
 }
 
+// Gets a candidate refenence motion vector from the given mode info
+// structure if one exists that matches the given reference frame.
+static int get_matching_candidate(
+  const MODE_INFO *candidate_mi,
+  MV_REFERENCE_FRAME ref_frame,
+  int_mv *c_mv
+) {
+  int ret_val = TRUE;
 
-// Gets a best matching candidate refenence motion vector
-// from the given mode info structure (if available)
-static int get_candidate_mvref(
+  if (ref_frame == candidate_mi->mbmi.ref_frame) {
+    c_mv->as_int = candidate_mi->mbmi.mv[0].as_int;
+  } else if (ref_frame == candidate_mi->mbmi.second_ref_frame) {
+    c_mv->as_int = candidate_mi->mbmi.mv[1].as_int;
+  } else {
+    ret_val = FALSE;
+  }
+
+  return ret_val;
+}
+
+// Gets candidate refenence motion vector(s) from the given mode info
+// structure if they exists and do NOT match the given reference frame.
+static void get_non_matching_candidates(
   const MODE_INFO *candidate_mi,
   MV_REFERENCE_FRAME ref_frame,
   MV_REFERENCE_FRAME *c_ref_frame,
@@ -52,61 +70,29 @@
   int_mv *c2_mv
 ) {
 
-  int ret_val = FALSE;
+  c_mv->as_int = 0;
   c2_mv->as_int = 0;
+  *c_ref_frame = INTRA_FRAME;
   *c2_ref_frame = INTRA_FRAME;
 
-  // Target ref frame matches candidate first ref frame
-  if (ref_frame == candidate_mi->mbmi.ref_frame) {
-    c_mv->as_int = candidate_mi->mbmi.mv[0].as_int;
-    *c_ref_frame = ref_frame;
-    ret_val = TRUE;
-
-    // Is there a second non zero vector we can use.
-    if ((candidate_mi->mbmi.second_ref_frame > INTRA_FRAME) &&
-        (candidate_mi->mbmi.mv[1].as_int != 0) &&
-        (candidate_mi->mbmi.mv[1].as_int != c_mv->as_int)) {
-      c2_mv->as_int = candidate_mi->mbmi.mv[1].as_int;
-      *c2_ref_frame = candidate_mi->mbmi.second_ref_frame;
+  // If first candidate not valid neither will be.
+  if (candidate_mi->mbmi.ref_frame > INTRA_FRAME) {
+    // First candidate
+    if (candidate_mi->mbmi.ref_frame != ref_frame) {
+      *c_ref_frame = candidate_mi->mbmi.ref_frame;
+      c_mv->as_int = candidate_mi->mbmi.mv[0].as_int;
     }
 
-  // Target ref frame matches candidate second ref frame
-  } else if (ref_frame == candidate_mi->mbmi.second_ref_frame) {
-    c_mv->as_int = candidate_mi->mbmi.mv[1].as_int;
-    *c_ref_frame = ref_frame;
-    ret_val = TRUE;
-
-    // Is there a second non zero vector we can use.
-    if ((candidate_mi->mbmi.ref_frame > INTRA_FRAME) &&
-        (candidate_mi->mbmi.mv[0].as_int != 0) &&
-        (candidate_mi->mbmi.mv[0].as_int != c_mv->as_int)) {
-      c2_mv->as_int = candidate_mi->mbmi.mv[0].as_int;
-      *c2_ref_frame = candidate_mi->mbmi.ref_frame;
-    }
-
-  // No ref frame matches so use first ref mv as first choice
-  } else if (candidate_mi->mbmi.ref_frame > INTRA_FRAME) {
-    c_mv->as_int = candidate_mi->mbmi.mv[0].as_int;
-    *c_ref_frame = candidate_mi->mbmi.ref_frame;
-    ret_val = TRUE;
-
-    // Is there a second non zero vector we can use.
+    // Second candidate
     if ((candidate_mi->mbmi.second_ref_frame > INTRA_FRAME) &&
-        (candidate_mi->mbmi.mv[1].as_int != 0) &&
-        (candidate_mi->mbmi.mv[1].as_int != c_mv->as_int)) {
-      c2_mv->as_int = candidate_mi->mbmi.mv[1].as_int;
+        (candidate_mi->mbmi.second_ref_frame != ref_frame)) {  // &&
+        // (candidate_mi->mbmi.mv[1].as_int != 0) &&
+        // (candidate_mi->mbmi.mv[1].as_int !=
+        // candidate_mi->mbmi.mv[0].as_int)) {
       *c2_ref_frame = candidate_mi->mbmi.second_ref_frame;
+      c2_mv->as_int = candidate_mi->mbmi.mv[1].as_int;
     }
-
-  // If only the second ref mv is valid:- (Should not trigger in current code
-  // base given current possible compound prediction options).
-  } else if (candidate_mi->mbmi.second_ref_frame > INTRA_FRAME) {
-    c_mv->as_int = candidate_mi->mbmi.mv[1].as_int;
-    *c_ref_frame = candidate_mi->mbmi.second_ref_frame;
-    ret_val = TRUE;
   }
-
-  return ret_val;
 }
 
 // Performs mv adjustment based on reference frame and clamps the MV
@@ -170,14 +156,20 @@
   int weight
 ) {
 
-  int i = *index;
+  int i;
+  int insert_point;
   int duplicate_found = FALSE;
 
-  // Check for duplicates. If there is one increment its score.
-  // Duplicate defined as being the same full pel vector with rounding.
+  // Check for duplicates. If there is one increase its score.
+  // We only compare vs the current top candidates.
+  insert_point = (*index < (MAX_MV_REF_CANDIDATES - 1))
+                 ? *index : (MAX_MV_REF_CANDIDATES - 1);
+
+  i = insert_point;
+  if (*index > i)
+    i++;
   while (i > 0) {
     i--;
-
     if (candidate_mv.as_int == mv_list[i].as_int) {
       duplicate_found = TRUE;
       mv_scores[i] += weight;
@@ -185,11 +177,13 @@
     }
   }
 
-  // If no duplicate was found add the new vector and give it a weight
-  if (!duplicate_found) {
-    mv_list[*index].as_int = candidate_mv.as_int;
-    mv_scores[*index] = weight;
-    i = *index;
+  // If no duplicate and the new candidate is good enough then add it.
+  if (!duplicate_found ) {
+    if (weight > mv_scores[insert_point]) {
+      mv_list[insert_point].as_int = candidate_mv.as_int;
+      mv_scores[insert_point] = weight;
+      i = insert_point;
+    }
     (*index)++;
   }
 
@@ -224,38 +218,32 @@
   int i;
   MODE_INFO *candidate_mi;
   MB_MODE_INFO * mbmi = &xd->mode_info_context->mbmi;
-  int_mv candidate_mvs[MAX_MV_REFS];
+  int_mv candidate_mvs[MAX_MV_REF_CANDIDATES];
   int_mv c_refmv;
-  MV_REFERENCE_FRAME c_ref_frame;
   int_mv c2_refmv;
+  MV_REFERENCE_FRAME c_ref_frame;
   MV_REFERENCE_FRAME c2_ref_frame;
-  int candidate_scores[MAX_MV_REFS];
+  int candidate_scores[MAX_MV_REF_CANDIDATES];
   int index = 0;
   int split_count = 0;
-  int ref_weight = 0;
-  int valid_mv_ref;
   int (*mv_ref_search)[2];
   int *ref_distance_weight;
 
   // Blank the reference vector lists and other local structures.
-  vpx_memset(mv_ref_list, 0, sizeof(int_mv) * MAX_MV_REFS);
-  vpx_memset(candidate_mvs, 0, sizeof(int_mv) * MAX_MV_REFS);
+  vpx_memset(mv_ref_list, 0, sizeof(int_mv) * MAX_MV_REF_CANDIDATES);
+  vpx_memset(candidate_mvs, 0, sizeof(int_mv) * MAX_MV_REF_CANDIDATES);
   vpx_memset(candidate_scores, 0, sizeof(candidate_scores));
 
-#if CONFIG_SUPERBLOCKS
-  if (mbmi->encoded_as_sb) {
+  if (mbmi->sb_type) {
     mv_ref_search = sb_mv_ref_search;
     ref_distance_weight = sb_ref_distance_weight;
   } else {
     mv_ref_search = mb_mv_ref_search;
     ref_distance_weight = mb_ref_distance_weight;
   }
-#else
-  mv_ref_search = mb_mv_ref_search;
-  ref_distance_weight = mb_ref_distance_weight;
-#endif
-  // Populate a list with candidate reference vectors from the
-  // spatial neighbours.
+
+  // We first scan for candidate vectors that match the current reference frame
+  // Look at nearest neigbours
   for (i = 0; i < 2; ++i) {
     if (((mv_ref_search[i][0] << 7) >= xd->mb_to_left_edge) &&
         ((mv_ref_search[i][1] << 7) >= xd->mb_to_top_edge)) {
@@ -263,95 +251,89 @@
       candidate_mi = here + mv_ref_search[i][0] +
                      (mv_ref_search[i][1] * xd->mode_info_stride);
 
-      valid_mv_ref = get_candidate_mvref(candidate_mi, ref_frame,
-                                         &c_ref_frame, &c_refmv,
-                                         &c2_ref_frame, &c2_refmv);
-
-      // If there is a valid MV candidate then add it to the list
-      if (valid_mv_ref) {
-        scale_mv(xd, ref_frame, c_ref_frame, &c_refmv, ref_sign_bias );
-        ref_weight = ref_distance_weight[i] +
-                     ((c_ref_frame == ref_frame) << 4);
-        split_count += (candidate_mi->mbmi.mode == SPLITMV);
-
+      if (get_matching_candidate(candidate_mi, ref_frame, &c_refmv)) {
+        clamp_mv(xd, &c_refmv);
         addmv_and_shuffle(candidate_mvs, candidate_scores,
-                          &index, c_refmv, ref_weight);
-
-        // If there is a second valid mv then add it as well.
-        if (c2_ref_frame > INTRA_FRAME) {
-          scale_mv(xd, ref_frame, c2_ref_frame, &c2_refmv, ref_sign_bias );
-          ref_weight = ref_distance_weight[i] +
-                       ((c2_ref_frame == ref_frame) << 4);
-
-          addmv_and_shuffle(candidate_mvs, candidate_scores,
-                            &index, c2_refmv, ref_weight);
-        }
+                          &index, c_refmv, ref_distance_weight[i] + 16);
       }
+      split_count += (candidate_mi->mbmi.mode == SPLITMV);
     }
   }
-
-  // Look at the corresponding vector in the last frame
+  // Look in the last frame
   candidate_mi = lf_here;
-  valid_mv_ref = get_candidate_mvref(candidate_mi, ref_frame,
-                                     &c_ref_frame, &c_refmv,
-                                     &c2_ref_frame, &c2_refmv);
-
-  // If there is a valid MV candidate then add it to the list
-  if (valid_mv_ref) {
-    scale_mv(xd, ref_frame, c_ref_frame, &c_refmv, ref_sign_bias );
-    ref_weight = 2 + ((c_ref_frame == ref_frame) << 4);
+  if (get_matching_candidate(candidate_mi, ref_frame, &c_refmv)) {
+    clamp_mv(xd, &c_refmv);
     addmv_and_shuffle(candidate_mvs, candidate_scores,
-                      &index, c_refmv, ref_weight);
-
-    // If there is a second valid mv then add it as well.
-    if (c2_ref_frame > INTRA_FRAME) {
-      scale_mv(xd, ref_frame, c2_ref_frame, &c2_refmv, ref_sign_bias );
-      ref_weight = ref_distance_weight[i] +
-                   ((c2_ref_frame == ref_frame) << 4);
-
-      addmv_and_shuffle(candidate_mvs, candidate_scores,
-                        &index, c2_refmv, ref_weight);
-    }
+                      &index, c_refmv, 18);
   }
-
-  // Populate a list with candidate reference vectors from the
-  // spatial neighbours.
-  for (i = 2; (i < MVREF_NEIGHBOURS) && (index < (MAX_MV_REFS - 2)); ++i) {
+  // More distant neigbours
+  for (i = 2; (i < MVREF_NEIGHBOURS) &&
+              (index < (MAX_MV_REF_CANDIDATES - 1)); ++i) {
     if (((mv_ref_search[i][0] << 7) >= xd->mb_to_left_edge) &&
         ((mv_ref_search[i][1] << 7) >= xd->mb_to_top_edge)) {
-
       candidate_mi = here + mv_ref_search[i][0] +
                      (mv_ref_search[i][1] * xd->mode_info_stride);
 
-      valid_mv_ref = get_candidate_mvref(candidate_mi, ref_frame,
-                                         &c_ref_frame, &c_refmv,
-                                         &c2_ref_frame, &c2_refmv);
+      if (get_matching_candidate(candidate_mi, ref_frame, &c_refmv)) {
+        clamp_mv(xd, &c_refmv);
+        addmv_and_shuffle(candidate_mvs, candidate_scores,
+                          &index, c_refmv, ref_distance_weight[i] + 16);
+      }
+    }
+  }
 
-      // If there is a valid MV candidate then add it to the list
-      if (valid_mv_ref) {
-        scale_mv(xd, ref_frame, c_ref_frame, &c_refmv, ref_sign_bias );
-        ref_weight = ref_distance_weight[i] +
-                     ((c_ref_frame == ref_frame) << 4);
+  // If we have not found enough candidates consider ones where the
+  // reference frame does not match. Break out when we have
+  // MAX_MV_REF_CANDIDATES candidates.
+  // Look first at spatial neighbours
+  if (index < (MAX_MV_REF_CANDIDATES - 1)) {
+    for (i = 0; i < MVREF_NEIGHBOURS; ++i) {
+      if (((mv_ref_search[i][0] << 7) >= xd->mb_to_left_edge) &&
+          ((mv_ref_search[i][1] << 7) >= xd->mb_to_top_edge)) {
 
-        addmv_and_shuffle(candidate_mvs, candidate_scores,
-                          &index, c_refmv, ref_weight);
+        candidate_mi = here + mv_ref_search[i][0] +
+                       (mv_ref_search[i][1] * xd->mode_info_stride);
 
-        // If there is a second valid mv then add it as well.
-        if (c2_ref_frame > INTRA_FRAME) {
-          scale_mv(xd, ref_frame, c2_ref_frame, &c2_refmv, ref_sign_bias );
-          ref_weight = ref_distance_weight[i] +
-                       ((c2_ref_frame == ref_frame) << 4);
+        get_non_matching_candidates(candidate_mi, ref_frame,
+                                    &c_ref_frame, &c_refmv,
+                                    &c2_ref_frame, &c2_refmv);
 
+        if (c_ref_frame != INTRA_FRAME) {
+          scale_mv(xd, ref_frame, c_ref_frame, &c_refmv, ref_sign_bias);
           addmv_and_shuffle(candidate_mvs, candidate_scores,
-                            &index, c2_refmv, ref_weight);
+                            &index, c_refmv, ref_distance_weight[i]);
         }
+
+        if (c2_ref_frame != INTRA_FRAME) {
+          scale_mv(xd, ref_frame, c2_ref_frame, &c2_refmv, ref_sign_bias);
+          addmv_and_shuffle(candidate_mvs, candidate_scores,
+                            &index, c2_refmv, ref_distance_weight[i]);
+        }
       }
+
+      if (index >= (MAX_MV_REF_CANDIDATES - 1)) {
+        break;
+      }
     }
   }
+  // Look at the last frame
+  if (index < (MAX_MV_REF_CANDIDATES - 1)) {
+    candidate_mi = lf_here;
+    get_non_matching_candidates(candidate_mi, ref_frame,
+                                &c_ref_frame, &c_refmv,
+                                &c2_ref_frame, &c2_refmv);
 
-  // Make sure we are able to add 0,0
-  if (index > (MAX_MV_REFS - 1)) {
-    index = (MAX_MV_REFS - 1);
+    if (c_ref_frame != INTRA_FRAME) {
+      scale_mv(xd, ref_frame, c_ref_frame, &c_refmv, ref_sign_bias);
+      addmv_and_shuffle(candidate_mvs, candidate_scores,
+                        &index, c_refmv, 2);
+    }
+
+    if (c2_ref_frame != INTRA_FRAME) {
+      scale_mv(xd, ref_frame, c2_ref_frame, &c2_refmv, ref_sign_bias);
+      addmv_and_shuffle(candidate_mvs, candidate_scores,
+                        &index, c2_refmv, 2);
+    }
   }
 
   // Define inter mode coding context.
@@ -383,14 +365,12 @@
   }
 
   // 0,0 is always a valid reference.
-  for (i = 0; i < index; ++i) {
+  for (i = 0; i < MAX_MV_REF_CANDIDATES; ++i) {
     if (candidate_mvs[i].as_int == 0)
       break;
   }
-  if (i == index) {
-    c_refmv.as_int = 0;
-    addmv_and_shuffle(candidate_mvs, candidate_scores,
-                      &index, c_refmv, candidate_scores[3]+1 );
+  if (i == MAX_MV_REF_CANDIDATES) {
+    candidate_mvs[MAX_MV_REF_CANDIDATES-1].as_int = 0;
   }
 
   // Copy over the candidate list.