86 строки
2.4 KiB
C
86 строки
2.4 KiB
C
/*
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* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "vp9/encoder/vp9_treewriter.h"
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static void cost(int *costs, vp9_tree tree, const vp9_prob *probs,
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int i, int c) {
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const vp9_prob prob = probs[i / 2];
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int b;
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for (b = 0; b <= 1; ++b) {
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const int cc = c + vp9_cost_bit(prob, b);
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const vp9_tree_index ii = tree[i + b];
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if (ii <= 0)
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costs[-ii] = cc;
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else
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cost(costs, tree, probs, ii, cc);
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}
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}
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void vp9_cost_tokens(int *costs, const vp9_prob *probs, vp9_tree tree) {
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cost(costs, tree, probs, 0, 0);
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}
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void vp9_cost_tokens_skip(int *costs, const vp9_prob *probs, vp9_tree tree) {
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assert(tree[0] <= 0 && tree[1] > 0);
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costs[-tree[0]] = vp9_cost_bit(probs[0], 0);
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cost(costs, tree, probs, 2, 0);
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}
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static void tree2tok(struct vp9_token *tokens, const vp9_tree_index *tree,
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int i, int v, int l) {
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v += v;
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++l;
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do {
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const vp9_tree_index j = tree[i++];
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if (j <= 0) {
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tokens[-j].value = v;
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tokens[-j].len = l;
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} else {
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tree2tok(tokens, tree, j, v, l);
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}
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} while (++v & 1);
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}
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void vp9_tokens_from_tree(struct vp9_token *tokens,
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const vp9_tree_index *tree) {
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tree2tok(tokens, tree, 0, 0, 0);
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}
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static unsigned int convert_distribution(unsigned int i, vp9_tree tree,
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unsigned int branch_ct[][2],
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const unsigned int num_events[]) {
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unsigned int left, right;
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if (tree[i] <= 0)
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left = num_events[-tree[i]];
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else
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left = convert_distribution(tree[i], tree, branch_ct, num_events);
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if (tree[i + 1] <= 0)
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right = num_events[-tree[i + 1]];
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else
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right = convert_distribution(tree[i + 1], tree, branch_ct, num_events);
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branch_ct[i >> 1][0] = left;
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branch_ct[i >> 1][1] = right;
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return left + right;
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}
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void vp9_tree_probs_from_distribution(vp9_tree tree,
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unsigned int branch_ct[/* n-1 */][2],
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const unsigned int num_events[/* n */]) {
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convert_distribution(0, tree, branch_ct, num_events);
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}
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