240 lines
7.7 KiB
C
240 lines
7.7 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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* This file contains the resampling functions between 48, 44, 32 and 24 kHz.
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* The description headers can be found in signal_processing_library.h
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*
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*/
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#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
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// interpolation coefficients
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static const int16_t kCoefficients48To32[2][8] = {
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{778, -2050, 1087, 23285, 12903, -3783, 441, 222},
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{222, 441, -3783, 12903, 23285, 1087, -2050, 778}
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};
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static const int16_t kCoefficients32To24[3][8] = {
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{767, -2362, 2434, 24406, 10620, -3838, 721, 90},
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{386, -381, -2646, 19062, 19062, -2646, -381, 386},
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{90, 721, -3838, 10620, 24406, 2434, -2362, 767}
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};
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static const int16_t kCoefficients44To32[4][9] = {
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{117, -669, 2245, -6183, 26267, 13529, -3245, 845, -138},
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{-101, 612, -2283, 8532, 29790, -5138, 1789, -524, 91},
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{50, -292, 1016, -3064, 32010, 3933, -1147, 315, -53},
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{-156, 974, -3863, 18603, 21691, -6246, 2353, -712, 126}
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};
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// Resampling ratio: 2/3
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// input: int32_t (normalized, not saturated) :: size 3 * K
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// output: int32_t (shifted 15 positions to the left, + offset 16384) :: size 2 * K
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// K: number of blocks
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void WebRtcSpl_Resample48khzTo32khz(const int32_t *In, int32_t *Out, size_t K)
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{
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/////////////////////////////////////////////////////////////
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// Filter operation:
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//
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// Perform resampling (3 input samples -> 2 output samples);
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// process in sub blocks of size 3 samples.
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int32_t tmp;
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size_t m;
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for (m = 0; m < K; m++)
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{
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tmp = 1 << 14;
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tmp += kCoefficients48To32[0][0] * In[0];
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tmp += kCoefficients48To32[0][1] * In[1];
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tmp += kCoefficients48To32[0][2] * In[2];
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tmp += kCoefficients48To32[0][3] * In[3];
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tmp += kCoefficients48To32[0][4] * In[4];
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tmp += kCoefficients48To32[0][5] * In[5];
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tmp += kCoefficients48To32[0][6] * In[6];
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tmp += kCoefficients48To32[0][7] * In[7];
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Out[0] = tmp;
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tmp = 1 << 14;
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tmp += kCoefficients48To32[1][0] * In[1];
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tmp += kCoefficients48To32[1][1] * In[2];
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tmp += kCoefficients48To32[1][2] * In[3];
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tmp += kCoefficients48To32[1][3] * In[4];
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tmp += kCoefficients48To32[1][4] * In[5];
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tmp += kCoefficients48To32[1][5] * In[6];
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tmp += kCoefficients48To32[1][6] * In[7];
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tmp += kCoefficients48To32[1][7] * In[8];
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Out[1] = tmp;
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// update pointers
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In += 3;
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Out += 2;
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}
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}
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// Resampling ratio: 3/4
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// input: int32_t (normalized, not saturated) :: size 4 * K
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// output: int32_t (shifted 15 positions to the left, + offset 16384) :: size 3 * K
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// K: number of blocks
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void WebRtcSpl_Resample32khzTo24khz(const int32_t *In, int32_t *Out, size_t K)
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{
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/////////////////////////////////////////////////////////////
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// Filter operation:
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//
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// Perform resampling (4 input samples -> 3 output samples);
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// process in sub blocks of size 4 samples.
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size_t m;
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int32_t tmp;
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for (m = 0; m < K; m++)
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{
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tmp = 1 << 14;
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tmp += kCoefficients32To24[0][0] * In[0];
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tmp += kCoefficients32To24[0][1] * In[1];
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tmp += kCoefficients32To24[0][2] * In[2];
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tmp += kCoefficients32To24[0][3] * In[3];
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tmp += kCoefficients32To24[0][4] * In[4];
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tmp += kCoefficients32To24[0][5] * In[5];
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tmp += kCoefficients32To24[0][6] * In[6];
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tmp += kCoefficients32To24[0][7] * In[7];
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Out[0] = tmp;
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tmp = 1 << 14;
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tmp += kCoefficients32To24[1][0] * In[1];
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tmp += kCoefficients32To24[1][1] * In[2];
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tmp += kCoefficients32To24[1][2] * In[3];
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tmp += kCoefficients32To24[1][3] * In[4];
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tmp += kCoefficients32To24[1][4] * In[5];
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tmp += kCoefficients32To24[1][5] * In[6];
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tmp += kCoefficients32To24[1][6] * In[7];
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tmp += kCoefficients32To24[1][7] * In[8];
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Out[1] = tmp;
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tmp = 1 << 14;
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tmp += kCoefficients32To24[2][0] * In[2];
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tmp += kCoefficients32To24[2][1] * In[3];
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tmp += kCoefficients32To24[2][2] * In[4];
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tmp += kCoefficients32To24[2][3] * In[5];
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tmp += kCoefficients32To24[2][4] * In[6];
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tmp += kCoefficients32To24[2][5] * In[7];
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tmp += kCoefficients32To24[2][6] * In[8];
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tmp += kCoefficients32To24[2][7] * In[9];
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Out[2] = tmp;
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// update pointers
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In += 4;
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Out += 3;
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}
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}
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//
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// fractional resampling filters
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// Fout = 11/16 * Fin
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// Fout = 8/11 * Fin
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//
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// compute two inner-products and store them to output array
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static void WebRtcSpl_ResampDotProduct(const int32_t *in1, const int32_t *in2,
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const int16_t *coef_ptr, int32_t *out1,
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int32_t *out2)
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{
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int32_t tmp1 = 16384;
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int32_t tmp2 = 16384;
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int16_t coef;
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coef = coef_ptr[0];
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tmp1 += coef * in1[0];
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tmp2 += coef * in2[-0];
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coef = coef_ptr[1];
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tmp1 += coef * in1[1];
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tmp2 += coef * in2[-1];
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coef = coef_ptr[2];
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tmp1 += coef * in1[2];
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tmp2 += coef * in2[-2];
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coef = coef_ptr[3];
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tmp1 += coef * in1[3];
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tmp2 += coef * in2[-3];
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coef = coef_ptr[4];
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tmp1 += coef * in1[4];
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tmp2 += coef * in2[-4];
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coef = coef_ptr[5];
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tmp1 += coef * in1[5];
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tmp2 += coef * in2[-5];
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coef = coef_ptr[6];
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tmp1 += coef * in1[6];
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tmp2 += coef * in2[-6];
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coef = coef_ptr[7];
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tmp1 += coef * in1[7];
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tmp2 += coef * in2[-7];
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coef = coef_ptr[8];
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*out1 = tmp1 + coef * in1[8];
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*out2 = tmp2 + coef * in2[-8];
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}
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// Resampling ratio: 8/11
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// input: int32_t (normalized, not saturated) :: size 11 * K
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// output: int32_t (shifted 15 positions to the left, + offset 16384) :: size 8 * K
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// K: number of blocks
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void WebRtcSpl_Resample44khzTo32khz(const int32_t *In, int32_t *Out, size_t K)
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{
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/////////////////////////////////////////////////////////////
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// Filter operation:
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//
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// Perform resampling (11 input samples -> 8 output samples);
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// process in sub blocks of size 11 samples.
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int32_t tmp;
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size_t m;
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for (m = 0; m < K; m++)
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{
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tmp = 1 << 14;
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// first output sample
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Out[0] = ((int32_t)In[3] << 15) + tmp;
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// sum and accumulate filter coefficients and input samples
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tmp += kCoefficients44To32[3][0] * In[5];
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tmp += kCoefficients44To32[3][1] * In[6];
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tmp += kCoefficients44To32[3][2] * In[7];
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tmp += kCoefficients44To32[3][3] * In[8];
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tmp += kCoefficients44To32[3][4] * In[9];
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tmp += kCoefficients44To32[3][5] * In[10];
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tmp += kCoefficients44To32[3][6] * In[11];
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tmp += kCoefficients44To32[3][7] * In[12];
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tmp += kCoefficients44To32[3][8] * In[13];
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Out[4] = tmp;
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// sum and accumulate filter coefficients and input samples
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WebRtcSpl_ResampDotProduct(&In[0], &In[17], kCoefficients44To32[0], &Out[1], &Out[7]);
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// sum and accumulate filter coefficients and input samples
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WebRtcSpl_ResampDotProduct(&In[2], &In[15], kCoefficients44To32[1], &Out[2], &Out[6]);
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// sum and accumulate filter coefficients and input samples
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WebRtcSpl_ResampDotProduct(&In[3], &In[14], kCoefficients44To32[2], &Out[3], &Out[5]);
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// update pointers
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In += 11;
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Out += 8;
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}
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}
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