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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.
*/
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
WebRtcIlbcfix_CbUpdateBestIndex.c
******************************************************************/
#include "modules/audio_coding/codecs/ilbc/cb_update_best_index.h"
#include "modules/audio_coding/codecs/ilbc/constants.h"
#include "modules/audio_coding/codecs/ilbc/defines.h"
void WebRtcIlbcfix_CbUpdateBestIndex(
int32_t CritNew, /* (i) New Potentially best Criteria */
int16_t CritNewSh, /* (i) Shift value of above Criteria */
size_t IndexNew, /* (i) Index of new Criteria */
int32_t cDotNew, /* (i) Cross dot of new index */
int16_t invEnergyNew, /* (i) Inversed energy new index */
int16_t energyShiftNew, /* (i) Energy shifts of new index */
int32_t *CritMax, /* (i/o) Maximum Criteria (so far) */
int16_t *shTotMax, /* (i/o) Shifts of maximum criteria */
size_t *bestIndex, /* (i/o) Index that corresponds to
maximum criteria */
int16_t *bestGain) /* (i/o) Gain in Q14 that corresponds
to maximum criteria */
{
int16_t shOld, shNew, tmp16;
int16_t scaleTmp;
int32_t gainW32;
/* Normalize the new and old Criteria to the same domain */
if (CritNewSh>(*shTotMax)) {
shOld=WEBRTC_SPL_MIN(31,CritNewSh-(*shTotMax));
shNew=0;
} else {
shOld=0;
shNew=WEBRTC_SPL_MIN(31,(*shTotMax)-CritNewSh);
}
/* Compare the two criterias. If the new one is better,
calculate the gain and store this index as the new best one
*/
if ((CritNew >> shNew) > (*CritMax >> shOld)) {
tmp16 = (int16_t)WebRtcSpl_NormW32(cDotNew);
tmp16 = 16 - tmp16;
/* Calculate the gain in Q14
Compensate for inverseEnergyshift in Q29 and that the energy
value was stored in a int16_t (shifted down 16 steps)
=> 29-14+16 = 31 */
scaleTmp = -energyShiftNew-tmp16+31;
scaleTmp = WEBRTC_SPL_MIN(31, scaleTmp);
gainW32 = ((int16_t)WEBRTC_SPL_SHIFT_W32(cDotNew, -tmp16) * invEnergyNew) >>
scaleTmp;
/* Check if criteria satisfies Gain criteria (max 1.3)
if it is larger set the gain to 1.3
(slightly different from FLP version)
*/
if (gainW32>21299) {
*bestGain=21299;
} else if (gainW32<-21299) {
*bestGain=-21299;
} else {
*bestGain=(int16_t)gainW32;
}
*CritMax=CritNew;
*shTotMax=CritNewSh;
*bestIndex = IndexNew;
}
return;
}