filllevel.h

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// SPDX-License-Identifier: AGPL-3.0-or-later
 
#ifndef FILLLEVEL_H
#define FILLLEVEL_H
 
#include <mutex>
 
class cBufferFillLevelLowPassFilter {
public:
    void Reset();
    void ResetFramesCounters();
    int GetFramesReceived() { std::lock_guard<std::mutex> lock(m_mutex); return m_receivedFrames; }
    int GetFramesPlayed() { std::lock_guard<std::mutex> lock(m_mutex); return m_writtenToAlsaFrames; }
    void ReceivedFrames(int count) { std::lock_guard<std::mutex> lock(m_mutex); m_receivedFrames += count; }
    void WroteFrames(int count) { std::lock_guard<std::mutex> lock(m_mutex); m_writtenToAlsaFrames += count; }
    double GetBufferFillLevelFramesAvg() { std::lock_guard<std::mutex> lock(m_mutex); return m_bufferFillLevelFramesAvg; }
    void SetMinBufferSizeFrames(int size) { std::lock_guard<std::mutex> lock(m_mutex); m_minBufferSizeFrames = size; }
    void UpdateAvgBufferFillLevel(int);
    bool IsSettled() { std::lock_guard<std::mutex> lock(m_mutex); return m_state == SETTLED; }
 
private:
    enum State {
        UNINITIALIZED,
        SETTLING,
        SETTLED,
    };
 
    constexpr static double FLOATING_AVERAGE_ALPHA_SETTLING = 0.02;
    constexpr static double FLOATING_AVERAGE_ALPHA_NORMAL = 0.002;
    constexpr static int SETTLING_DURATION_PACKETS = 30 / 0.16; // 30 seconds with one packet every 160ms
 
    std::mutex m_mutex;
    State m_state = UNINITIALIZED;
    int m_receivedFrames = 0;
    int m_writtenToAlsaFrames = 0;
    double m_bufferFillLevelFramesAvg = 0;
    double m_bufferFillLevelFramesTargetValue = 0;
    int m_frameCounter = 0;
    double m_floatingAverageAlpha = FLOATING_AVERAGE_ALPHA_NORMAL;
    int m_minBufferSizeFrames = 0;
 
    const char* StateToString(State d);
};
 
#endif