67 lines
2.1 KiB
C
67 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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* This file contains resampling functions between 48 kHz and nb/wb.
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* The description header can be found in signal_processing_library.h
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*
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*/
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#include "signal_processing_library.h"
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#include "resample_by_2_internal.h"
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#include <string.h>
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////////////////////////////
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///// 48 kHz -> 8 kHz /////
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////////////////////////////
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// 48 -> 8 resampler
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void WebRtcSpl_Resample48khzTo8khz(const int16_t* in, int16_t* out,
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WebRtcSpl_State48khzTo8khz* state, int32_t* tmpmem)
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{
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///// 48 --> 24 /////
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// int16_t in[480]
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// int32_t out[240]
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/////
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WebRtcSpl_DownBy2ShortToInt(in, 480, tmpmem + 256, state->S_48_24);
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///// 24 --> 24(LP) /////
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// int32_t in[240]
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// int32_t out[240]
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/////
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WebRtcSpl_LPBy2IntToInt(tmpmem + 256, 240, tmpmem + 16, state->S_24_24);
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///// 24 --> 16 /////
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// int32_t in[240]
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// int32_t out[160]
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/////
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// copy state to and from input array
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memcpy(tmpmem + 8, state->S_24_16, 8 * sizeof(int32_t));
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memcpy(state->S_24_16, tmpmem + 248, 8 * sizeof(int32_t));
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WebRtcSpl_Resample48khzTo32khz(tmpmem + 8, tmpmem, 80);
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///// 16 --> 8 /////
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// int32_t in[160]
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// int16_t out[80]
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/////
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WebRtcSpl_DownBy2IntToShort(tmpmem, 160, out, state->S_16_8);
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}
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// initialize state of 48 -> 8 resampler
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void WebRtcSpl_ResetResample48khzTo8khz(WebRtcSpl_State48khzTo8khz* state)
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{
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memset(state->S_48_24, 0, 8 * sizeof(int32_t));
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memset(state->S_24_24, 0, 16 * sizeof(int32_t));
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memset(state->S_24_16, 0, 8 * sizeof(int32_t));
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memset(state->S_16_8, 0, 8 * sizeof(int32_t));
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}
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