Method runDemodChannels

src/sdr/SDRPostThread.cpp:303–398

Handle active channels, channel 0 offset correction, de-interlacing and push data to demodulators

// Handle active channels, channel 0 offset correction, de-interlacing and push data to demodulators
void SDRPostThread::runDemodChannels(int channelBandwidth) {
    DemodulatorInstancePtr activeDemod = wxGetApp().getDemodMgr().getCurrentModem();

    // Calculate channel data size
    size_t chanDataSize = dataOut.size()/numChannels;

    // Channel for the 'active' demod that's displaying visual data
    int activeDemodChannel = -1;
    
    for (int i = 0, iMax = numChannels+1; i < iMax; i++) {
        demodChannelActive[i] = 0;
    }
    
    // Find nearest channel for each demodulator
    for (size_t i = 0; i < runDemods.size(); i++) {
        DemodulatorInstancePtr demod = runDemods[i];
        demodChannel[i] = getChannelAt(demod->getFrequency());
        if (demod == activeDemod) {
            activeDemodChannel = demodChannel[i];
        }
    }
    
    // Count the demods per-channel
    for (size_t i = 0; i < runDemods.size(); i++) {
        if (demodChannel[i] >= 0) {
            demodChannelActive[demodChannel[i]]++;
        }
    }

    // Run channels
    for (int i = 0; i < numChannels+1; i++) {
        bool doDemodVis = (activeDemodChannel == i) && (iqActiveDemodVisualQueue != nullptr);
        
        if (!doDemodVis && demodChannelActive[i] == 0) {
            // Nothing to do for this channel? continue.
            continue;
        }
        
        // Get a channel buffer
        DemodulatorThreadIQDataPtr demodDataOut = buffers.getBuffer();
        demodDataOut->frequency = chanCenters[i];
        demodDataOut->sampleRate = channelBandwidth;

        // Resize and update capacity of buffer if necessary
        if (demodDataOut->data.size() != chanDataSize) {
            if (demodDataOut->data.capacity() < chanDataSize) {
                demodDataOut->data.reserve(chanDataSize);
            }
            demodDataOut->data.resize(chanDataSize);
        }
        
        // Start copying interleaved data at given channel index
        int idx = i;
        
        // Extra channel wraps left side band of lowest channel
        // to fix frequency gap on right side of spectrum
        if (i == numChannels) {
            idx = (numChannels/2);