vp9/encoder/vp9_treewriter.c

   1 /*
   2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
   3  *
   4  *  Use of this source code is governed by a BSD-style license
   5  *  that can be found in the LICENSE file in the root of the source
   6  *  tree. An additional intellectual property rights grant can be found
   7  *  in the file PATENTS.  All contributing project authors may
   8  *  be found in the AUTHORS file in the root of the source tree.
   9  */
  10
  11 #include "vp9/encoder/vp9_treewriter.h"
  12
  13 static void tree2tok(struct vp9_token *tokens, const vp9_tree_index *tree,
  14                      int i, int v, int l) {
  15   v += v;
  16   ++l;
  17
  18   do {
  19     const vp9_tree_index j = tree[i++];
  20     if (j <= 0) {
  21       tokens[-j].value = v;
  22       tokens[-j].len = l;
  23     } else {
  24       tree2tok(tokens, tree, j, v, l);
  25     }
  26   } while (++v & 1);
  27 }
  28
  29 void vp9_tokens_from_tree(struct vp9_token *tokens,
  30                           const vp9_tree_index *tree) {
  31   tree2tok(tokens, tree, 0, 0, 0);
  32 }
  33
  34 static unsigned int convert_distribution(unsigned int i, vp9_tree tree,
  35                                          unsigned int branch_ct[][2],
  36                                          const unsigned int num_events[]) {
  37   unsigned int left, right;
  38
  39   if (tree[i] <= 0)
  40     left = num_events[-tree[i]];
  41   else
  42     left = convert_distribution(tree[i], tree, branch_ct, num_events);
  43
  44   if (tree[i + 1] <= 0)
  45     right = num_events[-tree[i + 1]];
  46   else
  47     right = convert_distribution(tree[i + 1], tree, branch_ct, num_events);
  48
  49   branch_ct[i >> 1][0] = left;
  50   branch_ct[i >> 1][1] = right;
  51   return left + right;
  52 }
  53
  54 void vp9_tree_probs_from_distribution(vp9_tree tree,
  55                                       unsigned int branch_ct[/* n-1 */][2],
  56                                       const unsigned int num_events[/* n */]) {
  57   convert_distribution(0, tree, branch_ct, num_events);
  58 }