Method startPlayback

src/core/ClientPuduMonitor.cpp:181–354

}

void ClientPuduMonitor::startPlayback()
{
    // Emit on every failure path so the RX mute installed at record-start
    // (or a prior manual-playback attempt) is always lifted.  The m_playing
    // guard below is the one exception — if we are already playing the mute
    // is legitimately held and must not be dropped.
    auto bail = [this]() {
        emit muteRxRequested(false);
        emit playbackStopped();
    };

    if (m_playing) return;
    if (m_recordedBytes <= 0) { bail(); return; }

    // ── Pick an output device + format ─────────────────────────────
    // int16 stereo at the sink's native rate.  Try 24 kHz first (zero-
    // resample fast path — typical on Linux); fall back to 48 kHz
    // (typical on macOS and Windows) with a one-shot r8brain upsample
    // of the whole captured buffer up-front.
    //
    // Prefer the device the user picked in Radio Settings > Audio
    // (m_outputDevice, seeded by MainWindow from AudioEngine).  Only
    // accept it if it is still present in the live audioOutputs() list
    // — a hotplug/unplug between selection and now would otherwise
    // strand us on a stale handle.  Mirrors AudioEngine::startSidetoneStream().
    QAudioDevice dev = QMediaDevices::defaultAudioOutput();
    if (!m_outputDevice.isNull()) {
        const auto outputs = QMediaDevices::audioOutputs();
        for (const auto& d : outputs) {
            if (d.id() == m_outputDevice.id()) { dev = d; break; }
        }
    }
    if (dev.isNull()) {
        AudioSummaryLogger::OpenFailureSummary failure;
        failure.path = QStringLiteral("Aetherial monitor playback");
        failure.backend = QStringLiteral("QAudioSink");
        failure.deviceDescription = QStringLiteral("Unavailable");
        failure.attemptedFormats = QStringLiteral("system default output");
        failure.failureReason = QStringLiteral("no audio output device");
        AudioSummaryLogger::logOpenFailure(failure);
        bail(); return;
    }

    // Negotiate the playback format via the shared factory (#3306, Phase 6b).
    // The monitor holds recorded Int16, so prefer Int16 (no conversion on a
    // normal device) and fall back to Float for Float-only WASAPI mixers — the
    // Int16->Float conversion below handles that case (#3231). The factory
    // supplies, in one place, the per-OS preferred rate (Win/Mac 48k to dodge
    // the WASAPI 24k resampler artifacts #2120 — same policy as the RX sink;
    // Linux native 24k) plus the 44.1k and preferredFormat fallbacks the old
    // hand-rolled ladder enumerated by hand. We walk it with isFormatSupported
    // (trusted here — that is exactly how #3231's Float-only devices are
    // detected, by Int16 being correctly rejected).
    QAudioFormat fmt;
    int sinkRate = kSampleRate;
    bool fallbackOccurred = false;
    QStringList fallbackReasons;
    QStringList attemptedFormats;