1b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org/* 2b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. 3b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org * 4b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org * Use of this source code is governed by a BSD-style license 5b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org * that can be found in the LICENSE file in the root of the source 6b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org * tree. An additional intellectual property rights grant can be found 7b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org * in the file PATENTS. All contributing project authors may 8b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org * be found in the AUTHORS file in the root of the source tree. 9b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org */ 10b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 11b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org/****************************************************************** 12b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 13b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org iLBC Speech Coder ANSI-C Source Code 14b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 15b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org WebRtcIlbcfix_HpInput.c 16b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 17b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org******************************************************************/ 18b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 19b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org#include "defines.h" 20b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 21b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org/*----------------------------------------------------------------* 22b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org * high-pass filter of input with *0.5 and saturation 23b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org *---------------------------------------------------------------*/ 24b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 25b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.orgvoid WebRtcIlbcfix_HpInput( 26fbda0fcf2f9e82c82bcaac138f44d4e5144f6e0dpbos@webrtc.org int16_t *signal, /* (i/o) signal vector */ 27fbda0fcf2f9e82c82bcaac138f44d4e5144f6e0dpbos@webrtc.org int16_t *ba, /* (i) B- and A-coefficients (2:nd order) 28b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org {b[0] b[1] b[2] -a[1] -a[2]} a[0] 29b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org is assumed to be 1.0 */ 30fbda0fcf2f9e82c82bcaac138f44d4e5144f6e0dpbos@webrtc.org int16_t *y, /* (i/o) Filter state yhi[n-1] ylow[n-1] 31b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org yhi[n-2] ylow[n-2] */ 32fbda0fcf2f9e82c82bcaac138f44d4e5144f6e0dpbos@webrtc.org int16_t *x, /* (i/o) Filter state x[n-1] x[n-2] */ 33fbda0fcf2f9e82c82bcaac138f44d4e5144f6e0dpbos@webrtc.org int16_t len) /* (i) Number of samples to filter */ 34b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org{ 35b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org int i; 36fbda0fcf2f9e82c82bcaac138f44d4e5144f6e0dpbos@webrtc.org int32_t tmpW32; 37fbda0fcf2f9e82c82bcaac138f44d4e5144f6e0dpbos@webrtc.org int32_t tmpW32b; 38b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 39b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org for (i=0; i<len; i++) { 40b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 41b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org /* 42b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org y[i] = b[0]*x[i] + b[1]*x[i-1] + b[2]*x[i-2] 43b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org + (-a[1])*y[i-1] + (-a[2])*y[i-2]; 44b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org */ 45b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 46b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org tmpW32 = WEBRTC_SPL_MUL_16_16(y[1], ba[3]); /* (-a[1])*y[i-1] (low part) */ 47b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org tmpW32 += WEBRTC_SPL_MUL_16_16(y[3], ba[4]); /* (-a[2])*y[i-2] (low part) */ 48b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org tmpW32 = (tmpW32>>15); 49b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org tmpW32 += WEBRTC_SPL_MUL_16_16(y[0], ba[3]); /* (-a[1])*y[i-1] (high part) */ 50b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org tmpW32 += WEBRTC_SPL_MUL_16_16(y[2], ba[4]); /* (-a[2])*y[i-2] (high part) */ 51b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org tmpW32 = (tmpW32<<1); 52b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 53b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org tmpW32 += WEBRTC_SPL_MUL_16_16(signal[i], ba[0]); /* b[0]*x[0] */ 54b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org tmpW32 += WEBRTC_SPL_MUL_16_16(x[0], ba[1]); /* b[1]*x[i-1] */ 55b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org tmpW32 += WEBRTC_SPL_MUL_16_16(x[1], ba[2]); /* b[2]*x[i-2] */ 56b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 57b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org /* Update state (input part) */ 58b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org x[1] = x[0]; 59b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org x[0] = signal[i]; 60b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 61b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org /* Rounding in Q(12+1), i.e. add 2^12 */ 62b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org tmpW32b = tmpW32 + 4096; 63b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 64b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org /* Saturate (to 2^28) so that the HP filtered signal does not overflow */ 65fbda0fcf2f9e82c82bcaac138f44d4e5144f6e0dpbos@webrtc.org tmpW32b = WEBRTC_SPL_SAT((int32_t)268435455, tmpW32b, (int32_t)-268435456); 66b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 67b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org /* Convert back to Q0 and multiply with 0.5 */ 68fbda0fcf2f9e82c82bcaac138f44d4e5144f6e0dpbos@webrtc.org signal[i] = (int16_t)WEBRTC_SPL_RSHIFT_W32(tmpW32b, 13); 69b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 70b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org /* Update state (filtered part) */ 71b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org y[2] = y[0]; 72b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org y[3] = y[1]; 73b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 74b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org /* upshift tmpW32 by 3 with saturation */ 75b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org if (tmpW32>268435455) { 76b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org tmpW32 = WEBRTC_SPL_WORD32_MAX; 77b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org } else if (tmpW32<-268435456) { 78b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org tmpW32 = WEBRTC_SPL_WORD32_MIN; 79b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org } else { 80b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org tmpW32 = WEBRTC_SPL_LSHIFT_W32(tmpW32, 3); 81b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org } 82b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 83fbda0fcf2f9e82c82bcaac138f44d4e5144f6e0dpbos@webrtc.org y[0] = (int16_t)(tmpW32 >> 16); 84fbda0fcf2f9e82c82bcaac138f44d4e5144f6e0dpbos@webrtc.org y[1] = (int16_t)((tmpW32 - WEBRTC_SPL_LSHIFT_W32((int32_t)y[0], 16))>>1); 85b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org } 86b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org 87b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org return; 88b015cbede88899f67a53fbbe581b02ce8e32794andrew@webrtc.org} 89