filllevel.cpp

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// SPDX-License-Identifier: AGPL-3.0-or-later
 
#include <algorithm>
 
#include "filllevel.h"
#include "logger.h"
 
void cBufferFillLevelLowPassFilter::Reset(void)
{
    m_state = UNINITIALIZED;
    m_bufferFillLevelFramesAvg = 0;
    m_frameCounter = 0;
}
 
void cBufferFillLevelLowPassFilter::ResetFramesCounters(void)
{
    m_receivedFrames = 0;
    m_writtenToAlsaFrames = 0;
}
 
void cBufferFillLevelLowPassFilter::UpdateAvgBufferFillLevel(int hardwareBufferFillLevelFrames)
{
    std::lock_guard<std::mutex> lock(m_mutex);
 
    int bufferFillLevelFrames = m_receivedFrames - m_writtenToAlsaFrames + hardwareBufferFillLevelFrames;
 
    m_bufferFillLevelFramesAvg = m_bufferFillLevelFramesAvg * (1 - m_floatingAverageAlpha) + bufferFillLevelFrames * m_floatingAverageAlpha;
 
    switch (m_state) {
        case UNINITIALIZED:
            m_floatingAverageAlpha = FLOATING_AVERAGE_ALPHA_SETTLING;
            m_bufferFillLevelFramesAvg = bufferFillLevelFrames; // init with current value to speed up settling
            m_frameCounter = 0;
            m_state = SETTLING;
            break;
        case SETTLING:
            if (m_frameCounter++ >= SETTLING_DURATION_PACKETS) {
                m_floatingAverageAlpha = FLOATING_AVERAGE_ALPHA_NORMAL;
                // fixate the current buffer fill level as target value, but guarantee a minimum buffer size
                m_bufferFillLevelFramesTargetValue = std::max((double)m_minBufferSizeFrames, m_bufferFillLevelFramesAvg);
                m_state = SETTLED;
            }
            break;
        case SETTLED:
            // nothing
            break;
    }
}
 
const char* cBufferFillLevelLowPassFilter::StateToString(State state)
{
    switch(state) {
        case UNINITIALIZED: return "UNINITIALIZED";
        case SETTLING: return "SETTLING";
        case SETTLED: return "SETTLED";
    }
    return "Unknown";
}