93 lines
3.4 KiB
C++
93 lines
3.4 KiB
C++
/*
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* Copyright (c) 2013 The WebRTC 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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#ifndef MODULES_AUDIO_PROCESSING_TRANSIENT_WPD_TREE_H_
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#define MODULES_AUDIO_PROCESSING_TRANSIENT_WPD_TREE_H_
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#include <stddef.h>
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#include <memory>
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#include "modules/audio_processing/transient/wpd_node.h"
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namespace webrtc {
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// Tree of a Wavelet Packet Decomposition (WPD).
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//
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// The root node contains all the data provided; for each node in the tree, the
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// left child contains the approximation coefficients extracted from the node,
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// and the right child contains the detail coefficients.
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// It preserves its state, so it can be multiple-called.
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//
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// The number of nodes in the tree will be 2 ^ levels - 1.
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//
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// Implementation details: Since the tree always will be a complete binary tree,
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// it is implemented using a single linear array instead of managing the
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// relationships in each node. For convience is better to use a array that
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// starts in 1 (instead of 0). Taking that into account, the following formulas
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// apply:
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// Root node index: 1.
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// Node(Level, Index in that level): 2 ^ Level + (Index in that level).
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// Left Child: Current node index * 2.
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// Right Child: Current node index * 2 + 1.
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// Parent: Current Node Index / 2 (Integer division).
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class WPDTree {
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public:
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// Creates a WPD tree using the data length and coefficients provided.
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WPDTree(size_t data_length,
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const float* high_pass_coefficients,
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const float* low_pass_coefficients,
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size_t coefficients_length,
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int levels);
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~WPDTree();
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// Returns the number of nodes at any given level.
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static int NumberOfNodesAtLevel(int level) { return 1 << level; }
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// Returns a pointer to the node at the given level and index(of that level).
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// Level goes from 0 to levels().
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// Index goes from 0 to the number of NumberOfNodesAtLevel(level) - 1.
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//
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// You can use the following formulas to get any node within the tree:
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// Notation: (Level, Index of node in that level).
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// Root node: (0/0).
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// Left Child: (Current node level + 1, Current node index * 2).
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// Right Child: (Current node level + 1, Current node index * 2 + 1).
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// Parent: (Current node level - 1, Current node index / 2) (Integer division)
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//
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// If level or index are out of bounds the function will return NULL.
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WPDNode* NodeAt(int level, int index);
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// Updates all the nodes of the tree with the new data. |data_length| must be
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// teh same that was used for the creation of the tree.
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// Returns 0 if correct, and -1 otherwise.
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int Update(const float* data, size_t data_length);
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// Returns the total number of levels below the root. Root is cosidered level
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// 0.
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int levels() const { return levels_; }
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// Returns the total number of nodes.
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int num_nodes() const { return num_nodes_; }
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// Returns the total number of leaves.
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int num_leaves() const { return 1 << levels_; }
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private:
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size_t data_length_;
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int levels_;
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int num_nodes_;
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std::unique_ptr<std::unique_ptr<WPDNode>[]> nodes_;
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};
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} // namespace webrtc
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#endif // MODULES_AUDIO_PROCESSING_TRANSIENT_WPD_TREE_H_
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