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bb547203bf
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}
86 lines
2.1 KiB
C
86 lines
2.1 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_Lsf2Poly.c
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******************************************************************/
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#include "defines.h"
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#include "lsf_to_lsp.h"
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#include "get_lsp_poly.h"
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#include "constants.h"
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void WebRtcIlbcfix_Lsf2Poly(
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int16_t *a, /* (o) predictor coefficients (order = 10) in Q12 */
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int16_t *lsf /* (i) line spectral frequencies in Q13 */
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) {
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int32_t f[2][6]; /* f[0][] and f[1][] corresponds to
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F1(z) and F2(z) respectivly */
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int32_t *f1ptr, *f2ptr;
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int16_t *a1ptr, *a2ptr;
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int32_t tmpW32;
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int16_t lsp[10];
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int i;
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/* Convert lsf to lsp */
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WebRtcIlbcfix_Lsf2Lsp(lsf, lsp, LPC_FILTERORDER);
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/* Get F1(z) and F2(z) from the lsp */
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f1ptr=f[0];
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f2ptr=f[1];
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WebRtcIlbcfix_GetLspPoly(&lsp[0],f1ptr);
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WebRtcIlbcfix_GetLspPoly(&lsp[1],f2ptr);
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/* for i = 5 down to 1
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Compute f1[i] += f1[i-1];
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and f2[i] += f2[i-1];
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*/
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f1ptr=&f[0][5];
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f2ptr=&f[1][5];
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for (i=5; i>0; i--)
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{
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(*f1ptr) += (*(f1ptr-1));
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(*f2ptr) -= (*(f2ptr-1));
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f1ptr--;
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f2ptr--;
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}
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/* Get the A(z) coefficients
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a[0] = 1.0
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for i = 1 to 5
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a[i] = (f1[i] + f2[i] + round)>>13;
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for i = 1 to 5
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a[11-i] = (f1[i] - f2[i] + round)>>13;
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*/
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a[0]=4096;
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a1ptr=&a[1];
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a2ptr=&a[10];
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f1ptr=&f[0][1];
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f2ptr=&f[1][1];
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for (i=5; i>0; i--)
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{
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tmpW32 = (*f1ptr) + (*f2ptr);
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*a1ptr = (int16_t)((tmpW32 + 4096) >> 13);
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tmpW32 = (*f1ptr) - (*f2ptr);
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*a2ptr = (int16_t)((tmpW32 + 4096) >> 13);
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a1ptr++;
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a2ptr--;
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f1ptr++;
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f2ptr++;
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}
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return;
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}
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