webrtc/src/voice_engine/level_indicator.cc

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/*
* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "level_indicator.h"
#include "module_common_types.h"
#include "signal_processing_library.h"
namespace webrtc {
namespace voe {
// Number of bars on the indicator.
// Note that the number of elements is specified because we are indexing it
// in the range of 0-32
const WebRtc_Word8 permutation[33] =
{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};
AudioLevel::AudioLevel() :
_absMax(0),
_count(0),
_currentLevel(0),
_currentLevelFullRange(0)
{
}
AudioLevel::~AudioLevel()
{
}
void
AudioLevel::Clear()
{
_absMax = 0;
_count = 0;
_currentLevel = 0;
_currentLevelFullRange = 0;
}
void
AudioLevel::ComputeLevel(const AudioFrame& audioFrame)
{
WebRtc_Word16 absValue(0);
// Check speech level (works for 2 channels as well)
absValue = WebRtcSpl_MaxAbsValueW16(
audioFrame.data_,
audioFrame.samples_per_channel_*audioFrame.num_channels_);
if (absValue > _absMax)
_absMax = absValue;
// Update level approximately 10 times per second
if (_count++ == kUpdateFrequency)
{
_currentLevelFullRange = _absMax;
_count = 0;
// Highest value for a WebRtc_Word16 is 0x7fff = 32767
// Divide with 1000 to get in the range of 0-32 which is the range of
// the permutation vector
WebRtc_Word32 position = _absMax/1000;
// Make it less likely that the bar stays at position 0. I.e. only if
// its in the range 0-250 (instead of 0-1000)
if ((position == 0) && (_absMax > 250))
{
position = 1;
}
_currentLevel = permutation[position];
// Decay the absolute maximum (divide by 4)
_absMax >>= 2;
}
}
WebRtc_Word8
AudioLevel::Level() const
{
return _currentLevel;
}
WebRtc_Word16
AudioLevel::LevelFullRange() const
{
return _currentLevelFullRange;
}
} // namespace voe
} // namespace webrtc