// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_LEVEL_CALCULATOR_H_
#define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_LEVEL_CALCULATOR_H_
#include "base/threading/thread_checker.h"
namespace content {
// This class is used by the WebRtcLocalAudioTrack to calculate the level of
// the audio signal. And the audio level will be eventually used by the volume
// animation UI.
// The algorithm used by this class is the same as how it is done in
// third_party/webrtc/voice_engine/level_indicator.cc.
class MediaStreamAudioLevelCalculator {
public:
MediaStreamAudioLevelCalculator();
~MediaStreamAudioLevelCalculator();
// Calculates the signal level of the audio data.
// Returns the absolute value of the amplitude of the signal.
int Calculate(const int16* audio_data, int number_of_channels,
int number_of_frames);
private:
// Used to DCHECK that the constructor and Calculate() are always called on
// the same audio thread. Note that the destructor will be called on a
// different thread, which can be either the main render thread or a new
// audio thread where WebRtcLocalAudioTrack::OnSetFormat() is called.
base::ThreadChecker thread_checker_;
int counter_;
int max_amplitude_;
int level_;
};
} // namespace content
#endif // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_LEVEL_CALCULATOR_H_