1e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard/* 2e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** Copyright 2003-2010, VisualOn, Inc. 3e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** 4e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** Licensed under the Apache License, Version 2.0 (the "License"); 5e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** you may not use this file except in compliance with the License. 6e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** You may obtain a copy of the License at 7e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** 8e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** http://www.apache.org/licenses/LICENSE-2.0 9e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** 10e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** Unless required by applicable law or agreed to in writing, software 11e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** distributed under the License is distributed on an "AS IS" BASIS, 12e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** See the License for the specific language governing permissions and 14e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** limitations under the License. 15e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard */ 16e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 17e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard/*********************************************************************** 18e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard* File: preemph.c * 19e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard* * 20e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard* Description: Preemphasis: filtering through 1 - g z^-1 * 21e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard* Preemph2 --> signal is multiplied by 2 * 22e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard* * 23e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard************************************************************************/ 24e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 25e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard#include "typedef.h" 26e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard#include "basic_op.h" 27e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 28e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgardvoid Preemph( 29e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard Word16 x[], /* (i/o) : input signal overwritten by the output */ 30e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard Word16 mu, /* (i) Q15 : preemphasis coefficient */ 31e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard Word16 lg, /* (i) : lenght of filtering */ 32e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard Word16 * mem /* (i/o) : memory (x[-1]) */ 33e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ) 34e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard{ 35e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard Word16 temp; 36e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard Word32 i, L_tmp; 37e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 38b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard temp = x[lg - 1]; 39e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 40e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard for (i = lg - 1; i > 0; i--) 41e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard { 42e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard L_tmp = L_deposit_h(x[i]); 43e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard L_tmp -= (x[i - 1] * mu)<<1; 44b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard x[i] = (L_tmp + 0x8000)>>16; 45e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard } 46e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 47e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard L_tmp = L_deposit_h(x[0]); 48e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard L_tmp -= ((*mem) * mu)<<1; 49b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard x[0] = (L_tmp + 0x8000)>>16; 50e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 51b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard *mem = temp; 52e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 53e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard return; 54e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard} 55e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 56e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 57e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgardvoid Preemph2( 58e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard Word16 x[], /* (i/o) : input signal overwritten by the output */ 59e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard Word16 mu, /* (i) Q15 : preemphasis coefficient */ 60e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard Word16 lg, /* (i) : lenght of filtering */ 61e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard Word16 * mem /* (i/o) : memory (x[-1]) */ 62e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ) 63e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard{ 64e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard Word16 temp; 65e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard Word32 i, L_tmp; 66e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 67b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard temp = x[lg - 1]; 68e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 69e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard for (i = (Word16) (lg - 1); i > 0; i--) 70e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard { 71e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard L_tmp = L_deposit_h(x[i]); 72e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard L_tmp -= (x[i - 1] * mu)<<1; 73e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard L_tmp = (L_tmp << 1); 74b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard x[i] = (L_tmp + 0x8000)>>16; 75e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard } 76e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 77e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard L_tmp = L_deposit_h(x[0]); 78e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard L_tmp -= ((*mem) * mu)<<1; 79e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard L_tmp = (L_tmp << 1); 80b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard x[0] = (L_tmp + 0x8000)>>16; 81e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 82b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard *mem = temp; 83e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 84e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard return; 85e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard} 86e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 87e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 88e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 89