Dave Sparks | 56c99cd | 2009-08-24 17:35:45 -0700 | [diff] [blame] | 1 | /*---------------------------------------------------------------------------- |
| 2 | * |
| 3 | * File: |
| 4 | * eas_pan.h |
| 5 | * |
| 6 | * Contents and purpose: |
| 7 | * Calculates left and right gain multipliers based on a pan value from -63 to +63 |
| 8 | * |
| 9 | * NOTES: |
| 10 | * The _CMX_PARSER and _MFI_PARSER preprocessor symbols determine |
| 11 | * whether the parser works for those particular file formats. |
| 12 | * |
| 13 | * Copyright Sonic Network Inc. 2005 |
The Android Open Source Project | 7df3010 | 2009-03-03 19:30:38 -0800 | [diff] [blame] | 14 | |
| 15 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 16 | * you may not use this file except in compliance with the License. |
| 17 | * You may obtain a copy of the License at |
| 18 | * |
| 19 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 20 | * |
| 21 | * Unless required by applicable law or agreed to in writing, software |
| 22 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 23 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 24 | * See the License for the specific language governing permissions and |
| 25 | * limitations under the License. |
Dave Sparks | 56c99cd | 2009-08-24 17:35:45 -0700 | [diff] [blame] | 26 | * |
| 27 | *---------------------------------------------------------------------------- |
| 28 | * Revision Control: |
| 29 | * $Revision: 82 $ |
| 30 | * $Date: 2006-07-10 11:45:19 -0700 (Mon, 10 Jul 2006) $ |
| 31 | *---------------------------------------------------------------------------- |
| 32 | */ |
| 33 | |
Aurimas Liutikas | 957372b | 2016-04-19 13:17:30 -0700 | [diff] [blame] | 34 | #ifndef _EAS_PAN_H |
Dave Sparks | 56c99cd | 2009-08-24 17:35:45 -0700 | [diff] [blame] | 35 | #define _EAS_PAN_H |
| 36 | |
| 37 | #include "eas_types.h" |
| 38 | |
| 39 | /*---------------------------------------------------------------------------- |
| 40 | * EAS_CalcPanControl() |
| 41 | *---------------------------------------------------------------------------- |
| 42 | * Purpose: |
| 43 | * Assign the left and right gain values corresponding to the given pan value. |
| 44 | * |
| 45 | * This routine uses sin/cos approximations for an equal power curve: |
| 46 | * |
| 47 | * sin(x) = (2-4*c)*x^2 + c + x |
| 48 | * cos(x) = (2-4*c)*x^2 + c - x |
| 49 | * |
| 50 | * where c = 1/sqrt(2) |
| 51 | * using the a0 + x*(a1 + x*a2) approach |
| 52 | * |
| 53 | * Inputs: |
| 54 | * pan - pan value (-63 to + 63) |
| 55 | * |
| 56 | * Outputs: |
| 57 | * pGainLeft linear gain multiplier for left channel (15-bit fraction) |
| 58 | * pGainRight linear gain multiplier for left channel (15-bit fraction) |
| 59 | * |
| 60 | * Side Effects: |
| 61 | *---------------------------------------------------------------------------- |
| 62 | */ |
| 63 | void EAS_CalcPanControl (EAS_INT pan, EAS_I16 *pGainLeft, EAS_I16 *pGainRight); |
| 64 | |
Aurimas Liutikas | 957372b | 2016-04-19 13:17:30 -0700 | [diff] [blame] | 65 | #endif /* #ifndef _EAS_PAN_H */ |
Dave Sparks | 56c99cd | 2009-08-24 17:35:45 -0700 | [diff] [blame] | 66 | |