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46 lines
1.5 KiB
C
46 lines
1.5 KiB
C
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/*
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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_GainDequant.c
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******************************************************************/
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#include "defines.h"
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#include "constants.h"
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/*----------------------------------------------------------------*
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* decoder for quantized gains in the gain-shape coding of
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* residual
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*---------------------------------------------------------------*/
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int16_t WebRtcIlbcfix_GainDequant(
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/* (o) quantized gain value (Q14) */
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int16_t index, /* (i) quantization index */
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int16_t maxIn, /* (i) maximum of unquantized gain (Q14) */
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int16_t stage /* (i) The stage of the search */
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){
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int16_t scale;
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const int16_t *gain;
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/* obtain correct scale factor */
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scale=WEBRTC_SPL_ABS_W16(maxIn);
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scale = WEBRTC_SPL_MAX(1638, scale); /* if lower than 0.1, set it to 0.1 */
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/* select the quantization table and return the decoded value */
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gain = WebRtcIlbcfix_kGain[stage];
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return((int16_t)((WEBRTC_SPL_MUL_16_16(scale, gain[index])+8192)>>14));
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}
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