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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_GainDequant.c
******************************************************************/
#include "modules/audio_coding/codecs/ilbc/gain_dequant.h"
#include "modules/audio_coding/codecs/ilbc/constants.h"
#include "modules/audio_coding/codecs/ilbc/defines.h"
/*----------------------------------------------------------------*
* decoder for quantized gains in the gain-shape coding of
* residual
*---------------------------------------------------------------*/
int16_t WebRtcIlbcfix_GainDequant(
/* (o) quantized gain value (Q14) */
int16_t index, /* (i) quantization index */
int16_t maxIn, /* (i) maximum of unquantized gain (Q14) */
int16_t stage /* (i) The stage of the search */
){
int16_t scale;
const int16_t *gain;
/* obtain correct scale factor */
scale=WEBRTC_SPL_ABS_W16(maxIn);
scale = WEBRTC_SPL_MAX(1638, scale); /* if lower than 0.1, set it to 0.1 */
/* select the quantization table and return the decoded value */
gain = WebRtcIlbcfix_kGain[stage];
return (int16_t)((scale * gain[index] + 8192) >> 14);
}
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