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webrtc/modules/audio_coding/NetEQ/main/source/peak_detection.c

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/*
* 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.
*/
/*
* Implementation of the peak detection used for finding correlation peaks.
*/
#include "dsp_helpfunctions.h"
#include "signal_processing_library.h"
/* Table of constants used in parabolic fit function WebRtcNetEQ_PrblFit */
const WebRtc_Word16 WebRtcNetEQ_kPrblCf[17][3] = { { 120, 32, 64 }, { 140, 44, 75 },
{ 150, 50, 80 }, { 160, 57, 85 },
{ 180, 72, 96 }, { 200, 89, 107 },
{ 210, 98, 112 }, { 220, 108, 117 },
{ 240, 128, 128 }, { 260, 150, 139 },
{ 270, 162, 144 }, { 280, 174, 149 },
{ 300, 200, 160 }, { 320, 228, 171 },
{ 330, 242, 176 }, { 340, 257, 181 },
{ 360, 288, 192 } };
WebRtc_Word16 WebRtcNetEQ_PeakDetection(WebRtc_Word16 *pw16_data, WebRtc_Word16 w16_dataLen,
WebRtc_Word16 w16_nmbPeaks, WebRtc_Word16 fs_mult,
WebRtc_Word16 *pw16_winIndex,
WebRtc_Word16 *pw16_winValue)
{
/* Local variables */
int i;
WebRtc_Word16 w16_tmp;
WebRtc_Word16 w16_tmp2;
WebRtc_Word16 indMin = 0;
WebRtc_Word16 indMax = 0;
/* Peak detection */
for (i = 0; i <= (w16_nmbPeaks - 1); i++)
{
if (w16_nmbPeaks == 1)
{
/*
* Single peak
* The parabola fit assumes that an extra point is available; worst case it gets
* a zero on the high end of the signal.
*/
w16_dataLen++;
}
pw16_winIndex[i] = WebRtcSpl_MaxIndexW16(pw16_data, (WebRtc_Word16) (w16_dataLen - 1));
if (i != w16_nmbPeaks - 1)
{
w16_tmp = pw16_winIndex[i] - 2; /* *fs_mult; */
indMin = WEBRTC_SPL_MAX(0, w16_tmp);
w16_tmp = pw16_winIndex[i] + 2; /* *fs_mult; */
w16_tmp2 = w16_dataLen - 1;
indMax = WEBRTC_SPL_MIN(w16_tmp2, w16_tmp);
}
if ((pw16_winIndex[i] != 0) && (pw16_winIndex[i] != (w16_dataLen - 2)))
{
/* Parabola fit*/
WebRtcNetEQ_PrblFit(&(pw16_data[pw16_winIndex[i] - 1]), &(pw16_winIndex[i]),
&(pw16_winValue[i]), fs_mult);
}
else
{
if (pw16_winIndex[i] == (w16_dataLen - 2))
{
if (pw16_data[pw16_winIndex[i]] > pw16_data[pw16_winIndex[i] + 1])
{
WebRtcNetEQ_PrblFit(&(pw16_data[pw16_winIndex[i] - 1]),
&(pw16_winIndex[i]), &(pw16_winValue[i]), fs_mult);
}
else if (pw16_data[pw16_winIndex[i]] <= pw16_data[pw16_winIndex[i] + 1])
{
pw16_winValue[i] = (pw16_data[pw16_winIndex[i]]
+ pw16_data[pw16_winIndex[i] + 1]) >> 1; /* lin approx */
pw16_winIndex[i] = (pw16_winIndex[i] * 2 + 1) * fs_mult;
}
}
else
{
pw16_winValue[i] = pw16_data[pw16_winIndex[i]];
pw16_winIndex[i] = pw16_winIndex[i] * 2 * fs_mult;
}
}
if (i != w16_nmbPeaks - 1)
{
WebRtcSpl_MemSetW16(&(pw16_data[indMin]), 0, (indMax - indMin + 1));
/* for (j=indMin; j<=indMax; j++) pw16_data[j] = 0; */
}
}
return 0;
}
WebRtc_Word16 WebRtcNetEQ_PrblFit(WebRtc_Word16 *pw16_3pts, WebRtc_Word16 *pw16_Ind,
WebRtc_Word16 *pw16_outVal, WebRtc_Word16 fs_mult)
{
/* Variables */
WebRtc_Word32 Num, Den;
WebRtc_Word32 temp;
WebRtc_Word16 flag, stp, strt, lmt;
WebRtc_UWord16 PFind[13];
if (fs_mult == 1)
{
PFind[0] = 0;
PFind[1] = 8;
PFind[2] = 16;
}
else if (fs_mult == 2)
{
PFind[0] = 0;
PFind[1] = 4;
PFind[2] = 8;
PFind[3] = 12;
PFind[4] = 16;
}
else if (fs_mult == 4)
{
PFind[0] = 0;
PFind[1] = 2;
PFind[2] = 4;
PFind[3] = 6;
PFind[4] = 8;
PFind[5] = 10;
PFind[6] = 12;
PFind[7] = 14;
PFind[8] = 16;
}
else
{
PFind[0] = 0;
PFind[1] = 1;
PFind[2] = 3;
PFind[3] = 4;
PFind[4] = 5;
PFind[5] = 7;
PFind[6] = 8;
PFind[7] = 9;
PFind[8] = 11;
PFind[9] = 12;
PFind[10] = 13;
PFind[11] = 15;
PFind[12] = 16;
}
/* Num = -3*pw16_3pts[0] + 4*pw16_3pts[1] - pw16_3pts[2]; */
/* Den = pw16_3pts[0] - 2*pw16_3pts[1] + pw16_3pts[2]; */
Num = WEBRTC_SPL_MUL_16_16(pw16_3pts[0],-3) + WEBRTC_SPL_MUL_16_16(pw16_3pts[1],4)
- pw16_3pts[2];
Den = pw16_3pts[0] + WEBRTC_SPL_MUL_16_16(pw16_3pts[1],-2) + pw16_3pts[2];
temp = (WebRtc_Word32) WEBRTC_SPL_MUL(Num, (WebRtc_Word32)120); /* need 32_16 really */
flag = 1;
stp = WebRtcNetEQ_kPrblCf[PFind[fs_mult]][0] - WebRtcNetEQ_kPrblCf[PFind[fs_mult - 1]][0];
strt = (WebRtcNetEQ_kPrblCf[PFind[fs_mult]][0]
+ WebRtcNetEQ_kPrblCf[PFind[fs_mult - 1]][0]) >> 1;
if (temp < (WebRtc_Word32) WEBRTC_SPL_MUL(-Den,(WebRtc_Word32)strt))
{
lmt = strt - stp;
while (flag)
{
if ((flag == fs_mult) || (temp
> (WebRtc_Word32) WEBRTC_SPL_MUL(-Den,(WebRtc_Word32)lmt)))
{
*pw16_outVal
= (WebRtc_Word16)
(((WebRtc_Word32) ((WebRtc_Word32) WEBRTC_SPL_MUL(Den,(WebRtc_Word32)WebRtcNetEQ_kPrblCf[PFind[fs_mult-flag]][1])
+ (WebRtc_Word32) WEBRTC_SPL_MUL(Num,(WebRtc_Word32)WebRtcNetEQ_kPrblCf[PFind[fs_mult-flag]][2])
+ WEBRTC_SPL_MUL_16_16(pw16_3pts[0],256))) >> 8);
*pw16_Ind = (*pw16_Ind) * (fs_mult << 1) - flag;
flag = 0;
}
else
{
flag++;
lmt -= stp;
}
}
}
else if (temp > (WebRtc_Word32) WEBRTC_SPL_MUL(-Den,(WebRtc_Word32)(strt+stp)))
{
lmt = strt + (stp << 1);
while (flag)
{
if ((flag == fs_mult) || (temp
< (WebRtc_Word32) WEBRTC_SPL_MUL(-Den,(WebRtc_Word32)lmt)))
{
WebRtc_Word32 temp_term_1, temp_term_2, temp_term_3;
temp_term_1 = WEBRTC_SPL_MUL(Den,
(WebRtc_Word32) WebRtcNetEQ_kPrblCf[PFind[fs_mult+flag]][1]);
temp_term_2 = WEBRTC_SPL_MUL(Num,
(WebRtc_Word32) WebRtcNetEQ_kPrblCf[PFind[fs_mult+flag]][2]);
temp_term_3 = WEBRTC_SPL_MUL_16_16(pw16_3pts[0],256);
*pw16_outVal
= (WebRtc_Word16) ((temp_term_1 + temp_term_2 + temp_term_3) >> 8);
*pw16_Ind = (*pw16_Ind) * (fs_mult << 1) + flag;
flag = 0;
}
else
{
flag++;
lmt += stp;
}
}
}
else
{
*pw16_outVal = pw16_3pts[1];
*pw16_Ind = (*pw16_Ind) * 2 * fs_mult;
}
return 0;
}
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