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In order to eliminate the WebRTC Subtree mirror in Chromium, WebRTC is moving the content of the src/webrtc directory up to the src/ directory. NOPRESUBMIT=true NOTREECHECKS=true NOTRY=true TBR=tommi@webrtc.org Bug: chromium:611808 Change-Id: Iac59c5b51b950f174119565bac87955a7994bc38 Reviewed-on: https://webrtc-review.googlesource.com/1560 Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org> Reviewed-by: Henrik Kjellander <kjellander@webrtc.org> Cr-Commit-Position: refs/heads/master@{#19845}
94 lines
3.2 KiB
C
94 lines
3.2 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_SimpleLpcAnalysis.c
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******************************************************************/
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#include "defines.h"
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#include "window32_w32.h"
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#include "bw_expand.h"
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#include "poly_to_lsf.h"
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#include "constants.h"
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/*----------------------------------------------------------------*
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* lpc analysis (subrutine to LPCencode)
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*---------------------------------------------------------------*/
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void WebRtcIlbcfix_SimpleLpcAnalysis(
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int16_t *lsf, /* (o) lsf coefficients */
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int16_t *data, /* (i) new block of speech */
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IlbcEncoder *iLBCenc_inst
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/* (i/o) the encoder state structure */
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) {
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int k;
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int scale;
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size_t is;
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int16_t stability;
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/* Stack based */
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int16_t A[LPC_FILTERORDER + 1];
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int32_t R[LPC_FILTERORDER + 1];
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int16_t windowedData[BLOCKL_MAX];
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int16_t rc[LPC_FILTERORDER];
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is=LPC_LOOKBACK+BLOCKL_MAX-iLBCenc_inst->blockl;
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WEBRTC_SPL_MEMCPY_W16(iLBCenc_inst->lpc_buffer+is,data,iLBCenc_inst->blockl);
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/* No lookahead, last window is asymmetric */
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for (k = 0; k < iLBCenc_inst->lpc_n; k++) {
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is = LPC_LOOKBACK;
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if (k < (iLBCenc_inst->lpc_n - 1)) {
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/* Hanning table WebRtcIlbcfix_kLpcWin[] is in Q15-domain so the output is right-shifted 15 */
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WebRtcSpl_ElementwiseVectorMult(windowedData, iLBCenc_inst->lpc_buffer, WebRtcIlbcfix_kLpcWin, BLOCKL_MAX, 15);
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} else {
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/* Hanning table WebRtcIlbcfix_kLpcAsymWin[] is in Q15-domain so the output is right-shifted 15 */
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WebRtcSpl_ElementwiseVectorMult(windowedData, iLBCenc_inst->lpc_buffer+is, WebRtcIlbcfix_kLpcAsymWin, BLOCKL_MAX, 15);
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}
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/* Compute autocorrelation */
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WebRtcSpl_AutoCorrelation(windowedData, BLOCKL_MAX, LPC_FILTERORDER, R, &scale);
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/* Window autocorrelation vector */
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WebRtcIlbcfix_Window32W32(R, R, WebRtcIlbcfix_kLpcLagWin, LPC_FILTERORDER + 1 );
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/* Calculate the A coefficients from the Autocorrelation using Levinson Durbin algorithm */
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stability=WebRtcSpl_LevinsonDurbin(R, A, rc, LPC_FILTERORDER);
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/*
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Set the filter to {1.0, 0.0, 0.0,...} if filter from Levinson Durbin algorithm is unstable
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This should basically never happen...
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*/
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if (stability!=1) {
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A[0]=4096;
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WebRtcSpl_MemSetW16(&A[1], 0, LPC_FILTERORDER);
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}
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/* Bandwidth expand the filter coefficients */
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WebRtcIlbcfix_BwExpand(A, A, (int16_t*)WebRtcIlbcfix_kLpcChirpSyntDenum, LPC_FILTERORDER+1);
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/* Convert from A to LSF representation */
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WebRtcIlbcfix_Poly2Lsf(lsf + k*LPC_FILTERORDER, A);
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}
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is=LPC_LOOKBACK+BLOCKL_MAX-iLBCenc_inst->blockl;
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WEBRTC_SPL_MEMCPY_W16(iLBCenc_inst->lpc_buffer,
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iLBCenc_inst->lpc_buffer+LPC_LOOKBACK+BLOCKL_MAX-is, is);
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return;
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}
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