Method OnSample

app/src/MDF4/Player.cpp:110–180

* @brief Caches per-channel sample values keyed by timestamp (or sample index as fallback). */

   * @brief Caches per-channel sample values keyed by timestamp (or sample index as fallback).
   */
  bool OnSample(uint64_t sample, uint64_t record_id, const std::vector<uint8_t>& record) override
  {
    if (record_id != m_recordId)
      return true;

    uint64_t cacheKey = sample;
    if (m_groupTimeChannel) {
      double ts          = 0.0;
      const bool success = GetEngValue(*m_groupTimeChannel, record_id, record, ts);
      if (!success)
        GetChannelValue(*m_groupTimeChannel, record_id, record, ts);

      cacheKey                   = static_cast<uint64_t>(ts * 1'000'000'000.0);
      m_timestampCache[cacheKey] = ts;
    }

    auto cacheIt = m_cache.find(cacheKey);
    if (cacheIt == m_cache.end())
      cacheIt = m_cache.emplace(cacheKey, std::vector<double>(m_allChannels.size(), 0.0)).first;

    auto activeIt = m_activeChannels.find(cacheKey);
    if (activeIt == m_activeChannels.end())
      activeIt =
        m_activeChannels.emplace(cacheKey, std::vector<bool>(m_allChannels.size(), false)).first;

    auto& values = cacheIt->second;
    auto& active = activeIt->second;

    std::vector<QString>* strings = nullptr;
    if (m_hasStringChannels) {
      auto strIt = m_stringCache.find(cacheKey);
      if (strIt == m_stringCache.end())
        strIt = m_stringCache.emplace(cacheKey, std::vector<QString>(m_allChannels.size())).first;

      strings = &strIt->second;
    }

    for (auto* channel : m_groupChannels) {
      if (!channel)
        continue;

      auto it = m_channelIndexMap.find(channel);
      if (it == m_channelIndexMap.end())
        continue;

      if (strings && isStringChannel(channel)) {
        std::string text;
        const bool success = GetEngValue(*channel, record_id, record, text);
        if (!success)
          (void)GetChannelValue(*channel, record_id, record, text);

        (*strings)[it->second] = QString::fromStdString(text);
        active[it->second]     = true;
        continue;
      }

      double value       = 0.0;
      const bool success = GetEngValue(*channel, record_id, record, value);