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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_FrameClassify.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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* Classification of subframes to localize start state
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*---------------------------------------------------------------*/
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int16_t WebRtcIlbcfix_FrameClassify(
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/* (o) Index to the max-energy sub frame */
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iLBC_Enc_Inst_t *iLBCenc_inst,
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/* (i/o) the encoder state structure */
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int16_t *residualFIX /* (i) lpc residual signal */
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){
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int16_t max, scale;
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int32_t ssqEn[NSUB_MAX-1];
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int16_t *ssqPtr;
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int32_t *seqEnPtr;
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int32_t maxW32;
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int16_t scale1;
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int16_t pos;
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int n;
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/*
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Calculate the energy of each of the 80 sample blocks
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in the draft the 4 first and last samples are windowed with 1/5...4/5
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and 4/5...1/5 respectively. To simplify for the fixpoint we have changed
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this to 0 0 1 1 and 1 1 0 0
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*/
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max = WebRtcSpl_MaxAbsValueW16(residualFIX, iLBCenc_inst->blockl);
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scale=WebRtcSpl_GetSizeInBits(WEBRTC_SPL_MUL_16_16(max,max));
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/* Scale to maximum 24 bits so that it won't overflow for 76 samples */
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scale = scale-24;
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scale1 = WEBRTC_SPL_MAX(0, scale);
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/* Calculate energies */
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ssqPtr=residualFIX + 2;
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seqEnPtr=ssqEn;
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for (n=(iLBCenc_inst->nsub-1); n>0; n--) {
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(*seqEnPtr) = WebRtcSpl_DotProductWithScale(ssqPtr, ssqPtr, 76, scale1);
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ssqPtr += 40;
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seqEnPtr++;
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}
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/* Scale to maximum 20 bits in order to allow for the 11 bit window */
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maxW32 = WebRtcSpl_MaxValueW32(ssqEn, (int16_t)(iLBCenc_inst->nsub-1));
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scale = WebRtcSpl_GetSizeInBits(maxW32) - 20;
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scale1 = WEBRTC_SPL_MAX(0, scale);
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/* Window each 80 block with the ssqEn_winTbl window to give higher probability for
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the blocks in the middle
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*/
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seqEnPtr=ssqEn;
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if (iLBCenc_inst->mode==20) {
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ssqPtr=(int16_t*)WebRtcIlbcfix_kStartSequenceEnrgWin+1;
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} else {
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ssqPtr=(int16_t*)WebRtcIlbcfix_kStartSequenceEnrgWin;
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}
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for (n=(iLBCenc_inst->nsub-1); n>0; n--) {
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(*seqEnPtr)=WEBRTC_SPL_MUL(((*seqEnPtr)>>scale1), (*ssqPtr));
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seqEnPtr++;
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ssqPtr++;
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}
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/* Extract the best choise of start state */
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pos = WebRtcSpl_MaxIndexW32(ssqEn, (int16_t)(iLBCenc_inst->nsub-1)) + 1;
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return(pos);
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}
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