70 lines
2.4 KiB
C++
70 lines
2.4 KiB
C++
/*
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* Copyright (c) 2014 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_SPLITTING_FILTER_H_
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#define MODULES_AUDIO_PROCESSING_SPLITTING_FILTER_H_
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#include <cstring>
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#include <memory>
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#include <vector>
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#include "modules/audio_processing/three_band_filter_bank.h"
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namespace webrtc {
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class IFChannelBuffer;
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struct TwoBandsStates {
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TwoBandsStates() {
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memset(analysis_state1, 0, sizeof(analysis_state1));
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memset(analysis_state2, 0, sizeof(analysis_state2));
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memset(synthesis_state1, 0, sizeof(synthesis_state1));
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memset(synthesis_state2, 0, sizeof(synthesis_state2));
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}
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static const int kStateSize = 6;
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int analysis_state1[kStateSize];
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int analysis_state2[kStateSize];
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int synthesis_state1[kStateSize];
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int synthesis_state2[kStateSize];
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};
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// Splitting filter which is able to split into and merge from 2 or 3 frequency
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// bands. The number of channels needs to be provided at construction time.
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//
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// For each block, Analysis() is called to split into bands and then Synthesis()
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// to merge these bands again. The input and output signals are contained in
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// IFChannelBuffers and for the different bands an array of IFChannelBuffers is
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// used.
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class SplittingFilter {
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public:
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SplittingFilter(size_t num_channels, size_t num_bands, size_t num_frames);
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~SplittingFilter();
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void Analysis(const IFChannelBuffer* data, IFChannelBuffer* bands);
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void Synthesis(const IFChannelBuffer* bands, IFChannelBuffer* data);
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private:
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// Two-band analysis and synthesis work for 640 samples or less.
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void TwoBandsAnalysis(const IFChannelBuffer* data, IFChannelBuffer* bands);
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void TwoBandsSynthesis(const IFChannelBuffer* bands, IFChannelBuffer* data);
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void ThreeBandsAnalysis(const IFChannelBuffer* data, IFChannelBuffer* bands);
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void ThreeBandsSynthesis(const IFChannelBuffer* bands, IFChannelBuffer* data);
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void InitBuffers();
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const size_t num_bands_;
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std::vector<TwoBandsStates> two_bands_states_;
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std::vector<std::unique_ptr<ThreeBandFilterBank>> three_band_filter_banks_;
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};
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} // namespace webrtc
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#endif // MODULES_AUDIO_PROCESSING_SPLITTING_FILTER_H_
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