mirror of
https://github.com/oxen-io/session-android.git
synced 2024-12-18 22:17:30 +00:00
90 lines
3.0 KiB
C
90 lines
3.0 KiB
C
/*
|
|
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
|
|
*
|
|
* Use of this source code is governed by a BSD-style license
|
|
* that can be found in the LICENSE file in the root of the source
|
|
* tree. An additional intellectual property rights grant can be found
|
|
* in the file PATENTS. All contributing project authors may
|
|
* be found in the AUTHORS file in the root of the source tree.
|
|
*/
|
|
|
|
/******************************************************************
|
|
|
|
iLBC Speech Coder ANSI-C Source Code
|
|
|
|
WebRtcIlbcfix_HpOutput.c
|
|
|
|
******************************************************************/
|
|
|
|
#include "defines.h"
|
|
|
|
/*----------------------------------------------------------------*
|
|
* high-pass filter of output and *2 with saturation
|
|
*---------------------------------------------------------------*/
|
|
|
|
void WebRtcIlbcfix_HpOutput(
|
|
int16_t *signal, /* (i/o) signal vector */
|
|
int16_t *ba, /* (i) B- and A-coefficients (2:nd order)
|
|
{b[0] b[1] b[2] -a[1] -a[2]} a[0]
|
|
is assumed to be 1.0 */
|
|
int16_t *y, /* (i/o) Filter state yhi[n-1] ylow[n-1]
|
|
yhi[n-2] ylow[n-2] */
|
|
int16_t *x, /* (i/o) Filter state x[n-1] x[n-2] */
|
|
int16_t len) /* (i) Number of samples to filter */
|
|
{
|
|
int i;
|
|
int32_t tmpW32;
|
|
int32_t tmpW32b;
|
|
|
|
for (i=0; i<len; i++) {
|
|
|
|
/*
|
|
y[i] = b[0]*x[i] + b[1]*x[i-1] + b[2]*x[i-2]
|
|
+ (-a[1])*y[i-1] + (-a[2])*y[i-2];
|
|
*/
|
|
|
|
tmpW32 = WEBRTC_SPL_MUL_16_16(y[1], ba[3]); /* (-a[1])*y[i-1] (low part) */
|
|
tmpW32 += WEBRTC_SPL_MUL_16_16(y[3], ba[4]); /* (-a[2])*y[i-2] (low part) */
|
|
tmpW32 = (tmpW32>>15);
|
|
tmpW32 += WEBRTC_SPL_MUL_16_16(y[0], ba[3]); /* (-a[1])*y[i-1] (high part) */
|
|
tmpW32 += WEBRTC_SPL_MUL_16_16(y[2], ba[4]); /* (-a[2])*y[i-2] (high part) */
|
|
tmpW32 = (tmpW32<<1);
|
|
|
|
tmpW32 += WEBRTC_SPL_MUL_16_16(signal[i], ba[0]); /* b[0]*x[0] */
|
|
tmpW32 += WEBRTC_SPL_MUL_16_16(x[0], ba[1]); /* b[1]*x[i-1] */
|
|
tmpW32 += WEBRTC_SPL_MUL_16_16(x[1], ba[2]); /* b[2]*x[i-2] */
|
|
|
|
/* Update state (input part) */
|
|
x[1] = x[0];
|
|
x[0] = signal[i];
|
|
|
|
/* Rounding in Q(12-1), i.e. add 2^10 */
|
|
tmpW32b = tmpW32 + 1024;
|
|
|
|
/* Saturate (to 2^26) so that the HP filtered signal does not overflow */
|
|
tmpW32b = WEBRTC_SPL_SAT((int32_t)67108863, tmpW32b, (int32_t)-67108864);
|
|
|
|
/* Convert back to Q0 and multiply with 2 */
|
|
signal[i] = (int16_t)WEBRTC_SPL_RSHIFT_W32(tmpW32b, 11);
|
|
|
|
/* Update state (filtered part) */
|
|
y[2] = y[0];
|
|
y[3] = y[1];
|
|
|
|
/* upshift tmpW32 by 3 with saturation */
|
|
if (tmpW32>268435455) {
|
|
tmpW32 = WEBRTC_SPL_WORD32_MAX;
|
|
} else if (tmpW32<-268435456) {
|
|
tmpW32 = WEBRTC_SPL_WORD32_MIN;
|
|
} else {
|
|
tmpW32 = WEBRTC_SPL_LSHIFT_W32(tmpW32, 3);
|
|
}
|
|
|
|
y[0] = (int16_t)(tmpW32 >> 16);
|
|
y[1] = (int16_t)((tmpW32 - WEBRTC_SPL_LSHIFT_W32((int32_t)y[0], 16))>>1);
|
|
|
|
}
|
|
|
|
return;
|
|
}
|