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/*----------------------------------------------------------------------------
*
* File:
* eas_chorusdata.h
*
* Contents and purpose:
* Contains the prototypes for the Chorus effect.
*
*
* Copyright Sonic Network Inc. 2006
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*----------------------------------------------------------------------------
* Revision Control:
* $Revision: 309 $
* $Date: 2006-09-12 18:52:45 -0700 (Tue, 12 Sep 2006) $
*----------------------------------------------------------------------------
*/
#ifndef _EAS_CHORUS_H
#define _EAS_CHORUS_H
#include "eas_types.h"
#include "eas_audioconst.h"
//defines for chorus
#define EAS_CHORUS_BYPASS_DEFAULT 1
#define EAS_CHORUS_PRESET_DEFAULT 0
#define EAS_CHORUS_RATE_DEFAULT 30
#define EAS_CHORUS_DEPTH_DEFAULT 39
#define EAS_CHORUS_LEVEL_DEFAULT 32767
#define EAS_CHORUS_LEVEL_MIN 0
#define EAS_CHORUS_LEVEL_MAX 32767
#define EAS_CHORUS_RATE_MIN 10
#define EAS_CHORUS_RATE_MAX 50
#define EAS_CHORUS_DEPTH_MIN 15
#define EAS_CHORUS_DEPTH_MAX 60
#define CHORUS_SIZE_MS 20
#define CHORUS_L_SIZE ((CHORUS_SIZE_MS*_OUTPUT_SAMPLE_RATE)/1000)
#define CHORUS_R_SIZE CHORUS_L_SIZE
#define CHORUS_SHAPE_SIZE 128
#define CHORUS_DELAY_MS 10
#define CHORUS_MAX_TYPE 4 // any Chorus numbers larger than this are invalid
typedef struct
{
EAS_I16 m_nRate;
EAS_I16 m_nDepth;
EAS_I16 m_nLevel;
} S_CHORUS_PRESET;
typedef struct
{
S_CHORUS_PRESET m_sPreset[CHORUS_MAX_TYPE]; //array of presets
} S_CHORUS_PRESET_BANK;
/* parameters for each Chorus */
typedef struct
{
EAS_I32 lfoLPhase;
EAS_I32 lfoRPhase;
EAS_I16 chorusIndexL;
EAS_I16 chorusIndexR;
EAS_U16 chorusTapPosition;
EAS_I16 m_nRate;
EAS_I16 m_nDepth;
EAS_I16 m_nLevel;
//delay lines used by the chorus, longer would sound better
EAS_PCM chorusDelayL[CHORUS_L_SIZE];
EAS_PCM chorusDelayR[CHORUS_R_SIZE];
EAS_BOOL bypass;
EAS_I8 preset;
EAS_I16 m_nCurrentChorus; // preset number for current Chorus
EAS_I16 m_nNextChorus; // preset number for next Chorus
S_CHORUS_PRESET pPreset;
S_CHORUS_PRESET_BANK m_sPreset;
} S_CHORUS_OBJECT;
/*----------------------------------------------------------------------------
* WeightedTap()
*----------------------------------------------------------------------------
* Purpose: Does fractional array look-up using linear interpolation
*
* first convert indexDesired to actual desired index by taking into account indexReference
* then do linear interpolation between two actual samples using fractional part
*
* Inputs:
* array: pointer to array of signed 16 bit values, typically either PCM data or control data
* indexReference: the circular buffer relative offset
* indexDesired: the fractional index we are looking up (16 bits index + 16 bits fraction)
* indexLimit: the total size of the array, used to compute buffer wrap
*
* Outputs:
* Value from the input array, linearly interpolated between two actual data values
*
*----------------------------------------------------------------------------
*/
static EAS_I16 WeightedTap(const EAS_I16 *array, EAS_I16 indexReference, EAS_I32 indexDesired, EAS_I16 indexLimit);
/*----------------------------------------------------------------------------
* ChorusReadInPresets()
*----------------------------------------------------------------------------
* Purpose: sets global Chorus preset bank to defaults
*
* Inputs:
*
* Outputs:
*
*----------------------------------------------------------------------------
*/
static EAS_RESULT ChorusReadInPresets(S_CHORUS_OBJECT *pChorusData);
/*----------------------------------------------------------------------------
* ChorusUpdate
*----------------------------------------------------------------------------
* Purpose:
* Update the Chorus preset parameters as required
*
* Inputs:
*
* Outputs:
*
*
* Side Effects:
* - chorus paramters will be changed
* - m_nCurrentChorus := m_nNextChorus
*----------------------------------------------------------------------------
*/
static EAS_RESULT ChorusUpdate(S_CHORUS_OBJECT* pChorusData);
#endif /* #ifndef _EAS_CHORUSDATA_H */
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