dce40cf804
use of int16_t/uint16_t. This is the upshot of a recommendation by henrik.lundin and kwiberg on an original small change ( https://webrtc-codereview.appspot.com/42569004/#ps1 ) to stop using int16_t just because values could fit in it, and is similar in nature to a previous "mass change to use size_t more" ( https://webrtc-codereview.appspot.com/23129004/ ) which also needed to be split up for review but to land all at once, since, like adding "const", such changes tend to cause a lot of transitive effects. This was be reviewed and approved in pieces: https://codereview.webrtc.org/1224093003 https://codereview.webrtc.org/1224123002 https://codereview.webrtc.org/1224163002 https://codereview.webrtc.org/1225133003 https://codereview.webrtc.org/1225173002 https://codereview.webrtc.org/1227163003 https://codereview.webrtc.org/1227203003 https://codereview.webrtc.org/1227213002 https://codereview.webrtc.org/1227893002 https://codereview.webrtc.org/1228793004 https://codereview.webrtc.org/1228803003 https://codereview.webrtc.org/1228823002 https://codereview.webrtc.org/1228823003 https://codereview.webrtc.org/1228843002 https://codereview.webrtc.org/1230693002 https://codereview.webrtc.org/1231713002 The change is being landed as TBR to all the folks who reviewed the above. BUG=chromium:81439 TEST=none R=andrew@webrtc.org, pbos@webrtc.org TBR=aluebs, andrew, asapersson, henrika, hlundin, jan.skoglund, kwiberg, minyue, pbos, pthatcher Review URL: https://codereview.webrtc.org/1230503003 . Cr-Commit-Position: refs/heads/master@{#9768}
89 lines
2.8 KiB
C
89 lines
2.8 KiB
C
/*
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* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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/******************************************************************
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iLBC Speech Coder ANSI-C Source Code
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WebRtcIlbcfix_HpInput.c
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******************************************************************/
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#include "defines.h"
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/*----------------------------------------------------------------*
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* high-pass filter of input with *0.5 and saturation
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*---------------------------------------------------------------*/
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void WebRtcIlbcfix_HpInput(
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int16_t *signal, /* (i/o) signal vector */
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int16_t *ba, /* (i) B- and A-coefficients (2:nd order)
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{b[0] b[1] b[2] -a[1] -a[2]} a[0]
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is assumed to be 1.0 */
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int16_t *y, /* (i/o) Filter state yhi[n-1] ylow[n-1]
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yhi[n-2] ylow[n-2] */
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int16_t *x, /* (i/o) Filter state x[n-1] x[n-2] */
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size_t len) /* (i) Number of samples to filter */
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{
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size_t i;
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int32_t tmpW32;
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int32_t tmpW32b;
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for (i=0; i<len; i++) {
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/*
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y[i] = b[0]*x[i] + b[1]*x[i-1] + b[2]*x[i-2]
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+ (-a[1])*y[i-1] + (-a[2])*y[i-2];
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*/
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tmpW32 = y[1] * ba[3]; /* (-a[1])*y[i-1] (low part) */
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tmpW32 += y[3] * ba[4]; /* (-a[2])*y[i-2] (low part) */
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tmpW32 = (tmpW32>>15);
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tmpW32 += y[0] * ba[3]; /* (-a[1])*y[i-1] (high part) */
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tmpW32 += y[2] * ba[4]; /* (-a[2])*y[i-2] (high part) */
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tmpW32 = (tmpW32<<1);
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tmpW32 += signal[i] * ba[0]; /* b[0]*x[0] */
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tmpW32 += x[0] * ba[1]; /* b[1]*x[i-1] */
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tmpW32 += x[1] * ba[2]; /* b[2]*x[i-2] */
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/* Update state (input part) */
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x[1] = x[0];
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x[0] = signal[i];
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/* Rounding in Q(12+1), i.e. add 2^12 */
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tmpW32b = tmpW32 + 4096;
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/* Saturate (to 2^28) so that the HP filtered signal does not overflow */
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tmpW32b = WEBRTC_SPL_SAT((int32_t)268435455, tmpW32b, (int32_t)-268435456);
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/* Convert back to Q0 and multiply with 0.5 */
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signal[i] = (int16_t)(tmpW32b >> 13);
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/* Update state (filtered part) */
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y[2] = y[0];
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y[3] = y[1];
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/* upshift tmpW32 by 3 with saturation */
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if (tmpW32>268435455) {
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tmpW32 = WEBRTC_SPL_WORD32_MAX;
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} else if (tmpW32<-268435456) {
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tmpW32 = WEBRTC_SPL_WORD32_MIN;
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} else {
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tmpW32 <<= 3;
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}
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y[0] = (int16_t)(tmpW32 >> 16);
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y[1] = (int16_t)((tmpW32 - (y[0] << 16)) >> 1);
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}
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return;
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}
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