247 lines
10 KiB
C
247 lines
10 KiB
C
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/*
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* Copyright 2009, The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef AUDIOEQUALIZER_H_
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#define AUDIOEQUALIZER_H_
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#include "AudioCommon.h"
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namespace android {
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class AudioShelvingFilter;
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class AudioPeakingFilter;
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// A parametric audio equalizer. Supports an arbitrary number of bands and
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// presets.
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// The EQ is composed of a low-shelf, zero or more peaking filters and a high
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// shelf, where each band has frequency and gain controls, and the peaking
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// filters have an additional bandwidth control.
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class AudioEqualizer {
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public:
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// Configuration of a single band.
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struct BandConfig {
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// Gain in millibel.
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int32_t gain;
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// Frequency in millihertz.
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uint32_t freq;
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// Bandwidth in cents (ignored on shelving filters).
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uint32_t bandwidth;
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};
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// Preset configuration.
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struct PresetConfig {
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// Human-readable name.
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const char * name;
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// An array of size nBands where each element is a configuration for the
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// corresponding band.
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const BandConfig * bandConfigs;
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};
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// This value is used when requesting current preset, and EQ is not using a
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// preset.
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static const int PRESET_CUSTOM = -1;
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// Get the required memory size for an instance of this class.
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// nBands Number of bands required in the instance.
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static size_t GetInstanceSize(int nBands);
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// Create an instance of this class.
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// If succeeds, a respective call is expected to freeInstance(), regardless
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// of who owns the context memory.
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// pMem A memory buffer of at least the size returned by
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// GetInstanceSize(), where the instance context is to be
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// stored. If NULL, it will be automatically allocated (using
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// malloc).
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// nBands Number of bands. Must be >= 2.
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// nChannels Number of input/output channels (interlaced).
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// sampleRate The input/output sample rate, in Hz.
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// presets The presets configuration. May be NULL, but in that case the
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// client is required not to call preset-related functions.
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// This array is owned by the client and is not copied. It
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// must be kept valid by the client as long as the instance is
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// alive.
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// nPresets Number of elements in the presets array.
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// returns The instance if success. NULL if pMem is NULL and allocation
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// failed.
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static AudioEqualizer * CreateInstance(void * pMem, int nBands,
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int nChannels,
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int sampleRate,
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const PresetConfig * presets,
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int nPresets);
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// Reconfiguration of the filter. Changes input/output format, but does not
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// alter current parameter values. Causes reset of the delay lines.
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// nChannels Number of input/output channels (interlaced).
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// sampleRate The input/output sample rate, in Hz.
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void configure(int nChannels, int sampleRate);
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// Resets the filter parameters to the following values:
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// frequency: 0
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// gain: 0
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// bandwidth: 1200 cents.
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// It also disables the filter. Does not clear the delay lines.
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void reset();
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// Clears delay lines. Does not alter parameter values.
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void clear();
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// Frees the object. Will free the memory if the object owned it, i.e. if
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// a NULL pointer was passed to CreateInstance as pMem.
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void free();
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// Sets gain value. Actual change will only take place upon commit().
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// This value will be remembered even if the filter is in disabled() state.
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// band The band to set the gain for.
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// millibel Gain value in millibel (1/100 of decibel).
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void setGain(int band, int32_t millibel);
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// Gets gain of a certain band. This is always the last value set (or
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// default value after reset).
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// band The band to get the gain for.
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// returns Gain value in millibel (1/100 of decibel).
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int32_t getGain(int band) const;
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// Sets cutoff frequency value. Actual change will only take place upon
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// commit().
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// This value will be remembered even if the filter is in disabled() state.
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// band The band to set the frequency for.
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// millihertz Frequency value in mHz.
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void setFrequency(int band, uint32_t millihertz);
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// Gets frequency of a certain band. This is always the last value set (or
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// default value after reset).
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// band The band to get the frequency for.
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// returns Frequency value in mHz.
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uint32_t getFrequency(int band) const;
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// Sets bandwidth value. Actual change will only take place upon commit().
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// This value will be remembered even if the filter is in disabled() state.
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// If called on the first or last band, this call is ignored.
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// band The band to set the frequency for.
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// cents Bandwidth value in cents (1/1200 octave).
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void setBandwidth(int band, uint32_t cents);
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// Gets bandwidth of a certain band. This is always the last value set (or
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// default value after reset). For the first and last bands, 0 is always
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// returned.
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// band The band to get the bandwidth for.
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// returns Bandwidth value in cents (1/1200 octave).
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uint32_t getBandwidth(int band) const;
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// Gets lower and upper boundaries of a band.
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// For the low shelf, the low bound is 0 and the high bound is the band
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// frequency.
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// For the high shelf, the low bound is the band frequency and the high
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// bound is Nyquist.
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// For the peaking filters, they are the gain[dB]/2 points.
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void getBandRange(int band, uint32_t & low, uint32_t & high) const;
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// Gets a human-readable name for a preset ID. Will return "Custom" if
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// PRESET_CUSTOM is passed.
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// preset The preset ID. Must be less than number of presets.
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const char * getPresetName(int preset) const;
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// Gets the number of presets.
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int getNumPresets() const;
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// Gets the currently set preset ID.
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// Will return PRESET_CUSTOM in case the EQ parameters have been modified
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// manually since a preset was set.
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int getPreset() const;
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// Sets the current preset by ID.
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// All the band parameters will be overridden.
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// Change will not be applied until commit() is called.
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// preset The preset ID. Must be less than number of presets.
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// PRESET_CUSTOM is NOT a valid value here.
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void setPreset(int preset);
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// Applies all parameter changes done to this point in time.
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// If the filter is disabled, the new parameters will take place when it is
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// enabled again. Does not introduce artifacts, unless immediate is set.
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// immediate Whether to apply change abruptly (ignored if filter is
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// disabled).
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void commit(bool immediate = false);
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// Process a buffer of input data. The input and output should contain
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// frameCount * nChannels interlaced samples. Processing can be done
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// in-place, by passing the same buffer as both arguments.
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// pIn Input buffer.
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// pOut Output buffer.
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// frameCount Number of frames to produce on each call to process().
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void process(const audio_sample_t * pIn, audio_sample_t * pOut,
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int frameCount);
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// Enables the filter, so it would start processing input. Does not
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// introduce artifacts, unless immediate is set.
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// immediate Whether to apply change abruptly.
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void enable(bool immediate = false);
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// Disabled (bypasses) the filter. Does not introduce artifacts, unless
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// immediate is set.
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// immediate Whether to apply change abruptly.
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void disable(bool immediate = false);
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// Returns the band with the maximum influence on a given frequency.
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// Result is unaffected by whether EQ is enabled or not, or by whether
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// changes have been committed or not.
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// targetFreq The target frequency, in millihertz.
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int getMostRelevantBand(uint32_t targetFreq) const;
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private:
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// Bottom frequency, in mHz.
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static const int kMinFreq = 20000;
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// Sample rate, in Hz.
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int mSampleRate;
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// Number of peaking filters. Total number of bands is +2.
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int mNumPeaking;
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// Preset configurations.
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const PresetConfig * mpPresets;
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// Number of elements in mpPresets;
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int mNumPresets;
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// Current preset.
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int mCurPreset;
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// Memory space to free when instance is deleted, or NULL if no memory is
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// owned.
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void * mpMem;
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// The low-shelving filter.
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AudioShelvingFilter * mpLowShelf;
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// The high-shelving filter.
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AudioShelvingFilter * mpHighShelf;
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// An array of size mNumPeaking of peaking filters.
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AudioPeakingFilter * mpPeakingFilters;
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// Constructor. Resets the filter (see reset()). Must call init() doing
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// anything else.
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// pMem Memory buffer for bands.
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// nChannels Number of input/output channels (interlaced).
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// sampleRate The input/output sample rate, in Hz.
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// ownMem Whether pMem is owned by me.
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// presets The presets configuration. May be NULL, but in that case the
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// client is required not to call preset-related functions.
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// This array is owned by the client and is not copied. It
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// must be kept valid by the client as long as the instance is
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// alive.
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// nPresets Number of elements in the presets array.
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AudioEqualizer(void * pMem, int nBands, int nChannels, int sampleRate,
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bool ownMem, const PresetConfig * presets, int nPresets);
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};
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}
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#endif // AUDIOEQUALIZER_H_
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