LVC_Mixer_SetTimeConstant.c revision 2c8e5cab3faa6d360e222b7a6c40a80083d021ac
12c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* 22c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * Copyright (C) 2004-2010 NXP Software 32c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * Copyright (C) 2010 The Android Open Source Project 42c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * 52c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * Licensed under the Apache License, Version 2.0 (the "License"); 62c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * you may not use this file except in compliance with the License. 72c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * You may obtain a copy of the License at 82c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * 92c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * http://www.apache.org/licenses/LICENSE-2.0 102c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * 112c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * Unless required by applicable law or agreed to in writing, software 122c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * distributed under the License is distributed on an "AS IS" BASIS, 132c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 142c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * See the License for the specific language governing permissions and 152c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * limitations under the License. 162c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent */ 172c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 182c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/************************************************************************/ 192c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* */ 202c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* Project:: */ 212c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* $Author: beq07716 $*/ 222c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* $Revision: 1000 $*/ 232c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* $Date: 2010-06-28 13:08:20 +0200 (Mon, 28 Jun 2010) $*/ 242c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* */ 252c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/************************************************************************/ 262c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 272c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent#include "LVM_Types.h" 282c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent#include "LVM_Macros.h" 292c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent#include "LVC_Mixer_Private.h" 302c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 312c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/************************************************************************/ 322c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* FUNCTION: */ 332c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* LVMixer3_SetTimeConstant */ 342c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* */ 352c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* DESCRIPTION: */ 362c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* This function calculates the step change for fractional gain for a */ 372c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* given time constant, sample rate and num channels */ 382c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* Delta=(2147483647*4*1000)/(NumChannels*SampleRate*Tc_millisec) */ 392c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* in Q 0.31 format */ 402c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* */ 412c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* PARAMETERS: */ 422c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* pStream - ptr to Instance Parameter Structure LVMixer3_st for an*/ 432c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* Audio Stream */ 442c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* Tc_millisec - TimeConstant i.e time required in milli second to */ 452c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* go from linear fractional gain of 0 to 0.99999999 */ 462c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* Fs - LVM_Fs_en enumerator for Sampling Frequency */ 472c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* NumChannels - Number of channels in Audio Stream 1=Mono, 2=Stereo */ 482c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* */ 492c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* UPDATES: */ 502c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* Delta - the step change for fractional gain per 4 samples */ 512c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* in Q0.31 format for a given Time Constant, */ 522c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* Sample Rate and NumChannels */ 532c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* RETURNS: */ 542c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* void */ 552c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/************************************************************************/ 562c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 572c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurentvoid LVC_Mixer_SetTimeConstant(LVMixer3_st *pStream, 582c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent LVM_INT32 Tc_millisec, 592c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent LVM_Fs_en Fs, 602c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent LVM_INT16 NumChannels) 612c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent{ 622c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent LVM_INT32 DeltaTable[9]={1073741824, 632c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 779132389, 642c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 715827882, 652c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 536870912, 662c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 389566194, 672c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 357913941, 682c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 268435456, 692c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 194783097, 702c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 178956971}; 712c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent Mix_Private_st *pInstance=(Mix_Private_st *)pStream->PrivateParams; 722c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent LVM_INT32 Delta=DeltaTable[Fs]; 732c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent Delta=Delta>>(NumChannels-1); 742c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 752c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent if(Tc_millisec==0) 762c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent Delta=0x7FFFFFFF; 772c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent else 782c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent Delta=Delta/Tc_millisec; 792c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 802c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent if(Delta==0) 812c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent Delta=1; // If Time Constant is so large that Delta is 0, assign minimum value to Delta 822c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 832c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent pInstance->Delta=Delta; // Delta=(2147483647*4*1000)/(NumChannels*SampleRate*Tc_millisec) in Q 0.31 format 842c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent} 85