77 lines
1.8 KiB
C++
77 lines
1.8 KiB
C++
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/*
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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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#include "level_indicator.h"
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namespace webrtc {
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// Array for adding smothing to level changes (ad-hoc).
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WebRtc_UWord32 perm[] =
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{0,1,2,3,4,4,5,5,5,5,6,6,6,6,6,7,7,7,7,8,8,8,9,9,9,9,9,9,9,9,9,9,9};
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LevelIndicator::LevelIndicator()
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: _max(0),
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_count(0),
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_currentLevel(0)
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{
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}
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LevelIndicator::~LevelIndicator()
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{
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}
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// Level is based on the highest absolute value for all samples.
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void LevelIndicator::ComputeLevel(const WebRtc_Word16* speech,
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const WebRtc_UWord16 nrOfSamples)
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{
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WebRtc_Word32 min = 0;
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for(WebRtc_UWord32 i = 0; i < nrOfSamples; i++)
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{
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if(_max < speech[i])
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{
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_max = speech[i];
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}
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if(min > speech[i])
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{
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min = speech[i];
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}
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}
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// Absolute max value.
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if(-min > _max)
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{
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_max = -min;
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}
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if(_count == TICKS_BEFORE_CALCULATION)
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{
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// Highest sample value maps directly to a level.
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WebRtc_Word32 position = _max / 1000;
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if ((position == 0) &&
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(_max > 250))
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{
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position = 1;
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}
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_currentLevel = perm[position];
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// The max value is decayed and stored so that it can be reused to slow
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// down decreases in level.
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_max = _max >> 1;
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_count = 0;
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} else {
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_count++;
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}
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}
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WebRtc_Word32 LevelIndicator::GetLevel()
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{
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return _currentLevel;
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}
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} // namespace webrtc
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