Method onBinaryMessage

src/core/TciServer.cpp:882–1061

// ── Binary message handler (TX audio from TCI client) ───────────────────

void TciServer::onBinaryMessage(const QByteArray& data)
{
    if (!m_audio) return;
    if (data.size() < static_cast<int>(sizeof(TciAudioHeader))) return;

    // Parse header
    TciAudioHeader hdr;
    std::memcpy(&hdr, data.constData(), sizeof(hdr));

    // Only accept TX_AUDIO_STREAM (type 2)
    if (hdr.type != 2) return;

    const int payloadBytes = data.size() - static_cast<int>(sizeof(TciAudioHeader));
    if (payloadBytes <= 0) return;

    const char* payload = data.constData() + sizeof(TciAudioHeader);

    // ── Convert TX audio to float32 stereo ─────────────────────────────────
    // WSJT-X channels field is garbage (FIFO reuse). readAudioData() writes
    // hdr.length floats to data[0..length-1]. Take the first hdr.length floats.
    QByteArray pcm;

    if (hdr.format == 3) {
        int validFloats = static_cast<int>(hdr.length);
        int availFloats = payloadBytes / static_cast<int>(sizeof(float));
        if (validFloats > availFloats) validFloats = availFloats;
        if (validFloats <= 0) return;

        pcm = QByteArray(payload,
                         validFloats * static_cast<int>(sizeof(float)));
    } else if (hdr.format == 0) {
        int validSamples = static_cast<int>(hdr.length);
        int availSamples = payloadBytes / static_cast<int>(sizeof(qint16));
        if (validSamples > availSamples) validSamples = availSamples;
        if (validSamples <= 0) return;

        auto* src = reinterpret_cast<const qint16*>(payload);
        pcm.resize(validSamples * static_cast<int>(sizeof(float)));
        auto* dst = reinterpret_cast<float*>(pcm.data());
        for (int i = 0; i < validSamples; ++i)
            dst[i] = src[i] / 32768.0f;
    }

    if (pcm.isEmpty()) return;

    int inputFramesSrcRate = 0;   // input frames at the client-declared rate (#3914)
    bool duplicatedStereo = false;

    // ─── TX resampling: client-declared rate → 24kHz (radio native DAX) ──
    // Resample from the rate the client declared in THIS frame (hdr.sampleRate),
    // not a hardcoded 48k. WSJT-X sends 48 kHz — the common path, unchanged — but
    // a client that negotiated 8/12/24 kHz (audio_samplerate) sends at that rate
    // and must be resampled from it, or every tone is mis-pitched and digital
    // decodes fail (#3306). Rebuild the per-session resampler only if the
    // declared rate changes (rare, mid-stream); a 24 kHz client gets a 1:1
    // resampler so the mono/stereo canonicalization below still runs.
    {
        const int declaredRate = static_cast<int>(hdr.sampleRate);