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      1 /*----------------------------------------------------------------------------
      2  *
      3  * File:
      4  * eas_chorusdata.h
      5  *
      6  * Contents and purpose:
      7  * Contains the prototypes for the Chorus effect.
      8  *
      9  *
     10  * Copyright Sonic Network Inc. 2006
     11 
     12  * Licensed under the Apache License, Version 2.0 (the "License");
     13  * you may not use this file except in compliance with the License.
     14  * You may obtain a copy of the License at
     15  *
     16  *      http://www.apache.org/licenses/LICENSE-2.0
     17  *
     18  * Unless required by applicable law or agreed to in writing, software
     19  * distributed under the License is distributed on an "AS IS" BASIS,
     20  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     21  * See the License for the specific language governing permissions and
     22  * limitations under the License.
     23  *
     24  *----------------------------------------------------------------------------
     25  * Revision Control:
     26  *   $Revision: 309 $
     27  *   $Date: 2006-09-12 18:52:45 -0700 (Tue, 12 Sep 2006) $
     28  *----------------------------------------------------------------------------
     29 */
     30 
     31 #ifndef _EAS_CHORUS_H
     32 #define _EAS_CHORUS_H
     33 
     34 #include "eas_types.h"
     35 #include "eas_audioconst.h"
     36 
     37 //defines for chorus
     38 
     39 #define EAS_CHORUS_BYPASS_DEFAULT   1
     40 #define EAS_CHORUS_PRESET_DEFAULT   0
     41 #define EAS_CHORUS_RATE_DEFAULT     30
     42 #define EAS_CHORUS_DEPTH_DEFAULT    39
     43 #define EAS_CHORUS_LEVEL_DEFAULT    32767
     44 
     45 #define EAS_CHORUS_LEVEL_MIN        0
     46 #define EAS_CHORUS_LEVEL_MAX        32767
     47 
     48 #define EAS_CHORUS_RATE_MIN         10
     49 #define EAS_CHORUS_RATE_MAX         50
     50 
     51 #define EAS_CHORUS_DEPTH_MIN        15
     52 #define EAS_CHORUS_DEPTH_MAX        60
     53 
     54 #define CHORUS_SIZE_MS 20
     55 #define CHORUS_L_SIZE ((CHORUS_SIZE_MS*_OUTPUT_SAMPLE_RATE)/1000)
     56 #define CHORUS_R_SIZE CHORUS_L_SIZE
     57 #define CHORUS_SHAPE_SIZE 128
     58 #define CHORUS_DELAY_MS 10
     59 
     60 #define CHORUS_MAX_TYPE         4   // any Chorus numbers larger than this are invalid
     61 
     62 typedef struct
     63 {
     64     EAS_I16             m_nRate;
     65     EAS_I16             m_nDepth;
     66     EAS_I16             m_nLevel;
     67 
     68 } S_CHORUS_PRESET;
     69 
     70 typedef struct
     71 {
     72     S_CHORUS_PRESET     m_sPreset[CHORUS_MAX_TYPE]; //array of presets
     73 
     74 } S_CHORUS_PRESET_BANK;
     75 
     76 /* parameters for each Chorus */
     77 typedef struct
     78 {
     79     EAS_I32 lfoLPhase;
     80     EAS_I32 lfoRPhase;
     81     EAS_I16 chorusIndexL;
     82     EAS_I16 chorusIndexR;
     83     EAS_U16 chorusTapPosition;
     84 
     85     EAS_I16 m_nRate;
     86     EAS_I16 m_nDepth;
     87     EAS_I16 m_nLevel;
     88 
     89     //delay lines used by the chorus, longer would sound better
     90     EAS_PCM chorusDelayL[CHORUS_L_SIZE];
     91     EAS_PCM chorusDelayR[CHORUS_R_SIZE];
     92 
     93     EAS_BOOL    bypass;
     94     EAS_I8      preset;
     95 
     96     EAS_I16     m_nCurrentChorus;           // preset number for current Chorus
     97     EAS_I16     m_nNextChorus;              // preset number for next Chorus
     98 
     99     S_CHORUS_PRESET         pPreset;
    100 
    101     S_CHORUS_PRESET_BANK    m_sPreset;
    102 
    103 } S_CHORUS_OBJECT;
    104 
    105 
    106 /*----------------------------------------------------------------------------
    107  * WeightedTap()
    108  *----------------------------------------------------------------------------
    109  * Purpose: Does fractional array look-up using linear interpolation
    110  *
    111  * first convert indexDesired to actual desired index by taking into account indexReference
    112  * then do linear interpolation between two actual samples using fractional part
    113  *
    114  * Inputs:
    115  * array: pointer to array of signed 16 bit values, typically either PCM data or control data
    116  * indexReference: the circular buffer relative offset
    117  * indexDesired: the fractional index we are looking up (16 bits index + 16 bits fraction)
    118  * indexLimit: the total size of the array, used to compute buffer wrap
    119  *
    120  * Outputs:
    121  * Value from the input array, linearly interpolated between two actual data values
    122  *
    123  *----------------------------------------------------------------------------
    124 */
    125 static EAS_I16 WeightedTap(const EAS_I16 *array, EAS_I16 indexReference, EAS_I32 indexDesired, EAS_I16 indexLimit);
    126 
    127 /*----------------------------------------------------------------------------
    128  * ChorusReadInPresets()
    129  *----------------------------------------------------------------------------
    130  * Purpose: sets global Chorus preset bank to defaults
    131  *
    132  * Inputs:
    133  *
    134  * Outputs:
    135  *
    136  *----------------------------------------------------------------------------
    137 */
    138 static EAS_RESULT ChorusReadInPresets(S_CHORUS_OBJECT *pChorusData);
    139 
    140 /*----------------------------------------------------------------------------
    141  * ChorusUpdate
    142  *----------------------------------------------------------------------------
    143  * Purpose:
    144  * Update the Chorus preset parameters as required
    145  *
    146  * Inputs:
    147  *
    148  * Outputs:
    149  *
    150  *
    151  * Side Effects:
    152  * - chorus paramters will be changed
    153  * - m_nCurrentChorus := m_nNextChorus
    154  *----------------------------------------------------------------------------
    155 */
    156 static EAS_RESULT ChorusUpdate(S_CHORUS_OBJECT* pChorusData);
    157 
    158 #endif /* #ifndef _EAS_CHORUSDATA_H */
    159 
    160 
    161