Sync

src/AlsaDriver.cpp

@@ -23,6 +23,7 @@
  */
 
 #include "pch.h"
+#include "PiPedalCommon.hpp"
 #include "util.hpp"
 #include <cmath>
 #include "Finally.hpp"
@@ -39,6 +40,7 @@
 #include "CrashGuard.hpp"
 #include <iostream>
 #include <iomanip>
+#include "ChannelRouterSettings.hpp"
 
 #include "CpuUse.hpp"
 
@@ -328,11 +330,34 @@ namespace pipedal
         bool inputSwapped = false;
         bool outputSwapped = false;
 
-        std::vector<float *> activeCaptureBuffers;
-        std::vector<float *> activePlaybackBuffers;
+        std::vector<std::vector<float>> allocatedBuffers;
 
-        std::vector<float *> captureBuffers;
-        std::vector<float *> playbackBuffers;
+        std::set<int64_t> usedOutputChannels;
+        std::vector<float*> deviceCaptureBuffers; 
+        std::vector<float*> devicePlaybackBuffers; 
+        float *zeroInputBuffer = nullptr;
+        float *discardOutputBuffer = nullptr;
+        std::vector<float *> mainCaptureBuffers;
+        std::vector<float *> mainPlaybackBuffers;
+
+        std::vector<float *> auxCaptureBuffers;
+        std::vector<float *> auxPlaybackBuffers;
+
+        std::vector<float *> sendCaptureBuffers;
+        std::vector<float *> sendPlaybackBuffers;
+
+        struct OutputBufferMix {
+            size_t outputChannel = 0;
+            std::vector<float*> inputBuffers;
+            float *outputBuffer = nullptr;
+        };
+
+        std::vector<OutputBufferMix> outputBufferMixes;
+
+
+
+        std::vector<float *> deviceCaptureBuffers;
+        std::vector<float *> devicePlaybackBuffers;
 
         std::vector<uint8_t> rawCaptureBuffer;
         std::vector<uint8_t> rawPlaybackBuffer;
@@ -742,7 +767,7 @@ namespace pipedal
         {
             int32_t *p = getCaptureBuffer<int32_t>(rawCaptureBuffer);
 
-            std::vector<float *> &buffers = this->captureBuffers;
+            std::vector<float *> &buffers = this->deviceCaptureBuffers;
             int channels = this->captureChannels;
             for (size_t frame = 0; frame < frames; ++frame)
             {
@@ -760,7 +785,7 @@ namespace pipedal
         {
             float *p = getCaptureBuffer<float>(rawCaptureBuffer);
 
-            std::vector<float *> &buffers = this->captureBuffers;
+            std::vector<float *> &buffers = this->deviceCaptureBuffers;
             int channels = this->captureChannels;
             for (size_t frame = 0; frame < frames; ++frame)
             {
@@ -776,7 +801,7 @@ namespace pipedal
         {
             int16_t *p = getCaptureBuffer<int16_t>(rawCaptureBuffer);
 
-            std::vector<float *> &buffers = this->captureBuffers;
+            std::vector<float *> &buffers = this->deviceCaptureBuffers;
             int channels = this->captureChannels;
             constexpr double scale = 1.0f / (std::numeric_limits<int16_t>::max() + 1L);
             for (size_t frame = 0; frame < frames; ++frame)
@@ -792,7 +817,7 @@ namespace pipedal
         {
             int16_t *p = getCaptureBuffer<int16_t>(rawCaptureBuffer);
 
-            std::vector<float *> &buffers = this->captureBuffers;
+            std::vector<float *> &buffers = this->deviceCaptureBuffers;
             int channels = this->captureChannels;
             constexpr float scale = 1.0f / (std::numeric_limits<int16_t>::max() + 1L);
             for (size_t frame = 0; frame < frames; ++frame)
@@ -809,7 +834,7 @@ namespace pipedal
         {
             int32_t *p = getCaptureBuffer<int32_t>(rawCaptureBuffer);
 
-            std::vector<float *> &buffers = this->captureBuffers;
+            std::vector<float *> &buffers = this->deviceCaptureBuffers;
             int channels = this->captureChannels;
             constexpr float scale = 1.0f / (std::numeric_limits<int32_t>::max() + 1L);
             for (size_t frame = 0; frame < frames; ++frame)
@@ -825,7 +850,7 @@ namespace pipedal
         {
             uint8_t *p = getCaptureBuffer<uint8_t>(rawCaptureBuffer);
 
-            std::vector<float *> &buffers = this->captureBuffers;
+            std::vector<float *> &buffers = this->deviceCaptureBuffers;
             int channels = this->captureChannels;
             constexpr float scale = 1.0f / (std::numeric_limits<int32_t>::max() + 1LL);
             for (size_t frame = 0; frame < frames; ++frame)
@@ -842,7 +867,7 @@ namespace pipedal
         {
             uint8_t *p = (uint8_t *)rawCaptureBuffer.data();
 
-            std::vector<float *> &buffers = this->captureBuffers;
+            std::vector<float *> &buffers = this->deviceCaptureBuffers;
             int channels = this->captureChannels;
             constexpr float scale = 1.0f / (std::numeric_limits<int32_t>::max() + 1LL);
             for (size_t frame = 0; frame < frames; ++frame)
@@ -859,7 +884,7 @@ namespace pipedal
         {
             int32_t *p = (int32_t *)rawCaptureBuffer.data();
 
-            std::vector<float *> &buffers = this->captureBuffers;
+            std::vector<float *> &buffers = this->deviceCaptureBuffers;
             int channels = this->captureChannels;
             constexpr float scale = 1.0f / (0x00FFFFFFL + 1L);
             for (size_t frame = 0; frame < frames; ++frame)
@@ -875,7 +900,7 @@ namespace pipedal
         {
             int32_t *p = (int32_t *)rawCaptureBuffer.data();
 
-            std::vector<float *> &buffers = this->captureBuffers;
+            std::vector<float *> &buffers = this->deviceCaptureBuffers;
             int channels = this->captureChannels;
             constexpr float scale = 1.0f / (0x00FFFFFFL + 1L);
             for (size_t frame = 0; frame < frames; ++frame)
@@ -891,7 +916,7 @@ namespace pipedal
         {
             int32_t *p = (int32_t *)rawCaptureBuffer.data();
 
-            std::vector<float *> &buffers = this->captureBuffers;
+            std::vector<float *> &buffers = this->deviceCaptureBuffers;
             int channels = this->captureChannels;
             constexpr float scale = 1.0f / (std::numeric_limits<int32_t>::max() + 1L);
             for (size_t frame = 0; frame < frames; ++frame)
@@ -907,7 +932,7 @@ namespace pipedal
         {
             int16_t *p = (int16_t *)rawPlaybackBuffer.data();
 
-            std::vector<float *> &buffers = this->playbackBuffers;
+            std::vector<float *> &buffers = this->devicePlaybackBuffers;
             int channels = this->playbackChannels;
             constexpr float scale = std::numeric_limits<int16_t>::max();
             for (size_t frame = 0; frame < frames; ++frame)
@@ -927,7 +952,7 @@ namespace pipedal
         {
             int16_t *p = (int16_t *)rawPlaybackBuffer.data();
 
-            std::vector<float *> &buffers = this->playbackBuffers;
+            std::vector<float *> &buffers = this->devicePlaybackBuffers;
             int channels = this->playbackChannels;
             constexpr float scale = std::numeric_limits<int16_t>::max();
             for (size_t frame = 0; frame < frames; ++frame)
@@ -947,7 +972,7 @@ namespace pipedal
         {
             int32_t *p = (int32_t *)rawPlaybackBuffer.data();
 
-            std::vector<float *> &buffers = this->playbackBuffers;
+            std::vector<float *> &buffers = this->devicePlaybackBuffers;
             int channels = this->playbackChannels;
             constexpr double scale = std::numeric_limits<int32_t>::max();
             for (size_t frame = 0; frame < frames; ++frame)
@@ -969,7 +994,7 @@ namespace pipedal
 
             int32_t *p = (int32_t *)rawPlaybackBuffer.data();
 
-            std::vector<float *> &buffers = this->playbackBuffers;
+            std::vector<float *> &buffers = this->devicePlaybackBuffers;
             int channels = this->playbackChannels;
             constexpr double scale = 0x00FFFFFF;
             for (size_t frame = 0; frame < frames; ++frame)
@@ -991,7 +1016,7 @@ namespace pipedal
 
             int32_t *p = (int32_t *)rawPlaybackBuffer.data();
 
-            std::vector<float *> &buffers = this->playbackBuffers;
+            std::vector<float *> &buffers = this->devicePlaybackBuffers;
             int channels = this->playbackChannels;
             constexpr double scale = 0x00FFFFFF;
             for (size_t frame = 0; frame < frames; ++frame)
@@ -1011,7 +1036,7 @@ namespace pipedal
         {
             int32_t *p = (int32_t *)rawPlaybackBuffer.data();
 
-            std::vector<float *> &buffers = this->playbackBuffers;
+            std::vector<float *> &buffers = this->devicePlaybackBuffers;
             int channels = this->playbackChannels;
             constexpr double scale = std::numeric_limits<int32_t>::max();
             for (size_t frame = 0; frame < frames; ++frame)
@@ -1031,7 +1056,7 @@ namespace pipedal
         {
             uint8_t *p = (uint8_t *)rawPlaybackBuffer.data();
 
-            std::vector<float *> &buffers = this->playbackBuffers;
+            std::vector<float *> &buffers = this->devicePlaybackBuffers;
             int channels = this->playbackChannels;
             constexpr double scale = std::numeric_limits<int32_t>::max();
             for (size_t frame = 0; frame < frames; ++frame)
@@ -1056,7 +1081,7 @@ namespace pipedal
         {
             uint8_t *p = (uint8_t *)rawPlaybackBuffer.data();
 
-            std::vector<float *> &buffers = this->playbackBuffers;
+            std::vector<float *> &buffers = this->devicePlaybackBuffers;
             int channels = this->playbackChannels;
             constexpr double scale = std::numeric_limits<int32_t>::max();
             for (size_t frame = 0; frame < frames; ++frame)
@@ -1082,7 +1107,7 @@ namespace pipedal
         {
             float *p = (float *)rawPlaybackBuffer.data();
 
-            std::vector<float *> &buffers = this->playbackBuffers;
+            std::vector<float *> &buffers = this->devicePlaybackBuffers;
             int channels = this->playbackChannels;
             for (size_t frame = 0; frame < frames; ++frame)
             {
@@ -1097,7 +1122,7 @@ namespace pipedal
         {
             float *p = (float *)rawPlaybackBuffer.data();
 
-            std::vector<float *> &buffers = this->playbackBuffers;
+            std::vector<float *> &buffers = this->devicePlaybackBuffers;
             int channels = this->playbackChannels;
             for (size_t frame = 0; frame < frames; ++frame)
             {
@@ -1127,9 +1152,9 @@ namespace pipedal
             }
         }
 
-        JackChannelSelection channelSelection;
+        ChannelSelection  channelSelection;
         bool open = false;
-        virtual void Open(const JackServerSettings &jackServerSettings, const JackChannelSelection &channelSelection)
+        virtual void Open(const JackServerSettings &jackServerSettings, const ChannelSelection &channelSelection)
         {
             terminateAudio_ = false;
             if (open)
@@ -1249,7 +1274,7 @@ namespace pipedal
             rawCaptureBuffer.resize(captureFrameSize * bufferSize * 2);
             memset(rawCaptureBuffer.data(), 0, rawCaptureBuffer.size());
 
-            AllocateBuffers(captureBuffers, captureChannels);
+            AllocateBuffers(deviceCaptureBuffers, captureChannels);
         }
 
         virtual std::string GetConfigurationDescription()
@@ -1260,8 +1285,15 @@ namespace pipedal
                 << ", " << GetAlsaFormatDescription(this->captureFormat)
                 << ", " << this->sampleRate
                 << ", " << this->bufferSize << "x" << this->numberOfBuffers
-                << ", in: " << this->InputBufferCount() << "/" << this->captureChannels
-                << ", out: " << this->OutputBufferCount() << "/" << this->playbackChannels);
+                << ", " << "device in: " << this->DeviceInputBufferCount() 
+                << ", " << "device out: " << this->DeviceOutputBufferCount()
+                << ", main in: " << this->MainInputBufferCount() 
+                << ", main out: " << this->MainOutputBufferCount() 
+                << ", aux in: " << this->AuxInputBufferCount() 
+                << ", aux out: " << this->AuxOutputBufferCount()
+                << ", send in: " << this->SendInputBufferCount() 
+                << ", send out: " << this->SendOutputBufferCount()
+            );
             return result;
         }
         void PreparePlaybackFunctions(snd_pcm_format_t playbackFormat)
@@ -1321,10 +1353,10 @@ namespace pipedal
             rawPlaybackBuffer.resize(playbackFrameSize * bufferSize);
             memset(rawPlaybackBuffer.data(), 0, playbackFrameSize * bufferSize);
 
-            AllocateBuffers(playbackBuffers, playbackChannels);
+            AllocateBuffers(devicePlaybackBuffers, playbackChannels);
         }
 
-        void OpenAudio(const JackServerSettings &jackServerSettings, const JackChannelSelection &channelSelection)
+        void OpenAudio(const JackServerSettings &jackServerSettings, const ChannelSelection &channelSelection)
         {
             std::lock_guard lock{restartMutex};
 
@@ -1717,7 +1749,7 @@ namespace pipedal
             }
             return 0;
         }
-        void AudioThread()
+        PIPEDAL_NON_INLINE void AudioThread()
         {
             SetThreadName("alsaDriver");
 
@@ -1797,6 +1829,19 @@ namespace pipedal
 
                     cpuUse.AddSample(ProfileCategory::Execute);
 
+                    // Perform any neccessary mixing of outputs.
+                    for (auto &bufferMix : outputBufferMixes)
+                    {
+                        float *outputBuffer = bufferMix.outputBuffer;
+                        for (auto &mixBuffer : bufferMix.inputBuffers)
+                        {
+                            for (size_t i = 0; i < framesRead; ++i)
+                            {
+                                outputBuffer[i] += mixBuffer[i];
+                            }
+                        }
+                    }
+
                     (this->*copyOutputFn)(framesRead);
                     cpuUse.AddSample(ProfileCategory::Driver);
                     // process.
@@ -1824,9 +1869,9 @@ namespace pipedal
             {
                 this->driverHost->OnAlsaDriverStopped();
                 // zero out input buffers.
-                for (size_t i = 0; i < this->captureBuffers.size(); ++i)
+                for (size_t i = 0; i < this->deviceCaptureBuffers.size(); ++i)
                 {
-                    float *pBuffer = captureBuffers[i];
+                    float *pBuffer = deviceCaptureBuffers[i];
                     for (size_t j = 0; j < this->bufferSize; ++j)
                     {
                         pBuffer[j] = 0;
@@ -1836,7 +1881,7 @@ namespace pipedal
                 {
                     while (!terminateAudio())
                     {
-                        std::this_thread::sleep_for(std::chrono::milliseconds(10));
+                        std::this_thread::sleep_for(std::chrono::milliseconds(1));
                         this->driverHost->OnProcess(this->bufferSize);
                     }
                 }
@@ -1849,63 +1894,129 @@ namespace pipedal
 
         bool alsaActive = false;
 
-        static int IndexFromPortName(const std::string &s)
-        {
-            auto pos = s.find_last_of('_');
-            if (pos == std::string::npos)
-            {
-                throw std::invalid_argument("Bad port name.");
-            }
-            const char *p = s.c_str() + (pos + 1);
 
-            int v = atoi(p);
-            if (v < 0)
+        PIPEDAL_NON_INLINE void AllocateInputChannels(
+            const std::vector<int64_t> &channelSelection,
+            std::vector<float*> &channelBuffers
+        ) {
+            size_t nChannels = channelSelection.size();
+            channelBuffers.resize(nChannels);
+
+            for (size_t i = 0; i < nChannels; ++i) 
             {
-                throw std::invalid_argument("Bad port name.");
+                int64_t deviceChannel = channelSelection[i];
+                if (deviceChannel == -1 || deviceChannel >= captureChannels) 
+                {
+                    channelBuffers[i] = zeroInputBuffer;
+                } 
+                else 
+                {
+                    channelBuffers[i] = deviceCaptureBuffers[deviceChannel];  
+                }
+            }
+        }
+        PIPEDAL_NON_INLINE void AddMixBuffer(int64_t outputChannel, float *mixBuffer) 
+        {
+            for (auto&bufferMix: outputBufferMixes)
+            {
+                if (bufferMix.outputChannel == outputChannel)
+                {
+                    bufferMix.inputBuffers.push_back(mixBuffer);
+                    return;
+                }
+            }
+            OutputBufferMix newMix;
+            newMix.outputChannel = outputChannel;
+            newMix.outputBuffer = devicePlaybackBuffers[outputChannel];
+            newMix.inputBuffers.push_back(mixBuffer);
+            outputBufferMixes.push_back(std::move(newMix));
+        }
+        PIPEDAL_NON_INLINE void AllocateOutputChannels(
+            const std::vector<int64_t> &channelSelection,
+            std::vector<float*> &channelBuffers
+        ) {
+            size_t nChannels = channelSelection.size();
+
+            channelBuffers.resize(nChannels);
+            for (size_t i = 0; i < nChannels; ++i) 
+            {
+                int64_t deviceChannel = channelSelection[i];
+                if (deviceChannel == -1 || deviceChannel >= playbackChannels) 
+                {
+                    if (discardOutputBuffer == nullptr) 
+                    {
+                        discardOutputBuffer = AllocateAudioBuffer();
+                    }
+                    channelBuffers[i] = discardOutputBuffer;
+                } 
+                else 
+                {
+                    if (!usedOutputChannels.contains(deviceChannel)) 
+                    {
+                        usedOutputChannels.insert(deviceChannel);
+                        channelBuffers[i] = deviceCaptureBuffers[deviceChannel];  
+                        
+                    } else {
+                        // Used once already. We need to mix down.
+                        float *mixBuffer = AllocateAudioBuffer();
+                        channelBuffers[i] = mixBuffer;
+                        AddMixBuffer(deviceChannel, mixBuffer);
+                    }
+                }
             }
-            return v;
         }
 
+
+
         bool activated = false;
-        virtual void Activate()
+        PIPEDAL_NON_INLINE virtual void Activate()
         {
             if (activated)
             {
                 throw PiPedalStateException("Already activated.");
             }
+
             activated = true;
 
-            this->activeCaptureBuffers.resize(channelSelection.GetInputAudioPorts().size());
+            // Reset previously allocated buffers.
+            usedOutputChannels.clear();
+            allocatedBuffers.resize(0);
 
-            int ix = 0;
-            for (auto &x : channelSelection.GetInputAudioPorts())
+
+            // Allocate device capture buffers.
+            zeroInputBuffer = AllocateAudioBuffer();
+            deviceCaptureBuffers.resize(captureChannels);
+            for (size_t i = 0; i < captureChannels; ++i)
             {
-                int sourceIndex = IndexFromPortName(x);
-                if (sourceIndex >= captureBuffers.size())
-                {
-                    Lv2Log::error(SS("Invalid audio input port: " << x));
-                }
-                else
-                {
-                    this->activeCaptureBuffers[ix++] = this->captureBuffers[sourceIndex];
-                }
+                deviceCaptureBuffers[i] = AllocateAudioBuffer();
+            }
+            devicePlaybackBuffers.resize(playbackChannels);
+            for (size_t i = 0; i < playbackChannels; ++i)
+            {
+                devicePlaybackBuffers[i] = AllocateAudioBuffer();
             }
 
-            this->activePlaybackBuffers.resize(channelSelection.GetOutputAudioPorts().size());
-
-            ix = 0;
-            for (auto &x : channelSelection.GetOutputAudioPorts())
-            {
-                int sourceIndex = IndexFromPortName(x);
-                if (sourceIndex >= playbackBuffers.size())
-                {
-                    Lv2Log::error(SS("Invalid audio output port: " << x));
-                }
-                else
-                {
-                    this->activePlaybackBuffers[ix++] = this->playbackBuffers[sourceIndex];
-                }
-            }
+            AllocateInputChannels(
+                channelSelection.mainInputChannels(),
+                this->mainCaptureBuffers);
+            AllocateOutputChannels(
+                channelSelection.mainOutputChannels(),
+                this->mainPlaybackBuffers
+            );
+            AllocateInputChannels(
+                channelSelection.auxInputChannels(),
+                this->auxCaptureBuffers);
+            AllocateOutputChannels(
+                channelSelection.auxOutputChannels(),
+                this->auxPlaybackBuffers
+            );
+            AllocateInputChannels(
+                channelSelection.sendInputChannels(),
+                this->sendCaptureBuffers);
+            AllocateOutputChannels(
+                channelSelection.sendOutputChannels(),
+                this->sendPlaybackBuffers
+            );
 
             audioThread = std::make_unique<std::jthread>([this]()
                                                          { AudioThread(); });
@@ -1941,10 +2052,43 @@ namespace pipedal
             this->alsaSequencer = alsaSequencer;
         }
 
-        virtual size_t InputBufferCount() const { return activeCaptureBuffers.size(); }
-        virtual float *GetInputBuffer(size_t channel) override
+        virtual size_t DeviceInputBufferCount() const override {
+            return deviceCaptureBuffers.size();
+        }
+        virtual size_t DeviceOutputBufferCount() const override {
+            return devicePlaybackBuffers.size();
+        }
+
+
+        virtual size_t MainInputBufferCount() const { return mainCaptureBuffers.size(); }
+        virtual float *GetMainInputBuffer(size_t channel) override
         {
-            return activeCaptureBuffers[channel];
+            if (channel >= (int64_t)mainCaptureBuffers.size()) 
+            {
+                throw std::runtime_error("Argument out of range.");
+            }
+            return mainCaptureBuffers[channel];
+        }
+        virtual size_t AuxInputBufferCount() const { return auxCaptureBuffers.size(); }
+        virtual float *GetAuxInputBuffer(size_t channel) override
+        {
+            return auxCaptureBuffers[channel];
+        }
+        virtual size_t AuxOutputBufferCount() const { 
+            return auxPlaybackBuffers.size(); }
+        virtual float *GetAuxOutputBuffer(size_t channel) override
+        {
+            return auxPlaybackBuffers[channel];
+        }
+        virtual size_t SendInputBufferCount() const { return sendCaptureBuffers.size(); }
+        virtual float *GetSendInputBuffer(size_t channel) override
+        {
+            return sendCaptureBuffers[channel];
+        }
+        virtual size_t SendOutputBufferCount() const { return sendPlaybackBuffers.size(); }
+        virtual float *GetSendOutputBuffer(size_t channel) override
+        {
+            return sendPlaybackBuffers[channel];
         }
 
         virtual size_t GetMidiInputEventCount() override
@@ -1956,27 +2100,30 @@ namespace pipedal
             return this->midiEvents.data();
         }
 
-        virtual size_t OutputBufferCount() const { return activePlaybackBuffers.size(); }
-        virtual float *GetOutputBuffer(size_t channel) override
+        virtual size_t MainOutputBufferCount() const { return mainPlaybackBuffers.size(); }
+        virtual float *GetMainOutputBuffer(size_t channel) override
         {
-            return activePlaybackBuffers[channel];
+            return mainPlaybackBuffers[channel];
         }
 
-        void FreeBuffers(std::vector<float *> &buffer)
-        {
-            for (size_t i = 0; i < buffer.size(); ++i)
-            {
-                delete[] buffer[i];
-                buffer[i] = 0;
-            }
-            buffer.clear();
+        float* AllocateAudioBuffer() {
+            std::vector<float> buffer;
+            buffer.resize(this->bufferSize);
+            float*pBuffer = buffer.data();
+            allocatedBuffers.push_back(std::move(buffer));
+            return pBuffer;
         }
         void DeleteBuffers()
         {
-            activeCaptureBuffers.clear();
-            activePlaybackBuffers.clear();
-            FreeBuffers(this->playbackBuffers);
-            FreeBuffers(this->captureBuffers);
+            mainCaptureBuffers.clear();
+            mainPlaybackBuffers.clear();
+            auxCaptureBuffers.clear();
+            auxPlaybackBuffers.clear();
+            sendCaptureBuffers.clear();
+            sendPlaybackBuffers.clear();
+            zeroInputBuffer = nullptr;
+            discardOutputBuffer = nullptr;
+            allocatedBuffers.clear();
         }
         virtual void Close()
         {
@@ -2241,7 +2388,7 @@ namespace pipedal
                 {
                     value += 1.0f * (c) / (128.0 * 256.0 * 256.0);
                 }
-                this->playbackBuffers[c][i] = value;
+                this->devicePlaybackBuffers[c][i] = value;
             }
         }
 
@@ -2257,7 +2404,7 @@ namespace pipedal
             for (size_t c = 0; c < captureChannels; ++c)
             {
                 float error =
-                    this->captureBuffers[c][i] - this->playbackBuffers[c][i];
+                    this->deviceCaptureBuffers[c][i] - this->devicePlaybackBuffers[c][i];
 
                 assert(std::abs(error) < 4e-5);
             }

src/AlsaDriverTest.cpp

@@ -218,16 +218,16 @@ public:
         if (testType == TestType::NullTest) return;
 
 
-        size_t inputs = audioDriver->InputBufferCount();
-        size_t outputs = audioDriver->OutputBufferCount();
+        size_t inputs = audioDriver->MainInputBufferCount();
+        size_t outputs = audioDriver->MainOutputBufferCount();
 
         for (size_t i = 0; i < inputs; ++i)
         {
-            inputBuffers[i] = audioDriver->GetInputBuffer(i);
+            inputBuffers[i] = audioDriver->GetMainInputBuffer(i);
         }
         for (size_t i = 0; i < outputs; ++i)
         {
-            outputBuffers[i] = audioDriver->GetOutputBuffer(i);
+            outputBuffers[i] = audioDriver->GetMainOutputBuffer(i);
         }
         if (this->testType == TestType::Oscillator)
         {

src/AudioDriver.hpp

@@ -35,6 +35,8 @@ namespace pipedal {
 
     using ProcessCallback = std::function<void (size_t)>;
 
+    class ChannelSelection;
+
 
     class AudioDriverHost {
     public:
@@ -58,14 +60,26 @@ namespace pipedal {
         virtual size_t GetMidiInputEventCount() = 0;
         virtual MidiEvent*GetMidiEvents() = 0;
 
-        virtual size_t InputBufferCount() const = 0;
-        virtual float*GetInputBuffer(size_t channel) = 0;
+        virtual size_t DeviceInputBufferCount() const = 0;
+        virtual size_t DeviceOutputBufferCount() const = 0;
+        virtual size_t MainInputBufferCount() const = 0;
+        virtual float*GetMainInputBuffer(size_t channel) = 0;
+        virtual size_t MainOutputBufferCount() const = 0;
+        virtual float*GetMainOutputBuffer(size_t channe) = 0;
 
 
-        virtual size_t OutputBufferCount() const = 0;
-        virtual float*GetOutputBuffer(size_t channe) = 0;
+        virtual size_t AuxInputBufferCount() const = 0;
+        virtual float*GetAuxInputBuffer(size_t channel) = 0;
+        virtual size_t AuxOutputBufferCount() const = 0;
+        virtual float*GetAuxOutputBuffer(size_t channel) = 0;
 
-        virtual void Open(const JackServerSettings & jackServerSettings,const JackChannelSelection &channelSelection) = 0;
+        virtual size_t SendInputBufferCount() const = 0;
+        virtual float*GetSendInputBuffer(size_t channel) = 0;
+        virtual size_t SendOutputBufferCount() const = 0;
+        virtual float*GetSendOutputBuffer(size_t channel) = 0;
+
+
+        virtual void Open(const JackServerSettings & jackServerSettings,const ChannelSelection &channelSelection) = 0;
         virtual void SetAlsaSequencer(AlsaSequencer::ptr alsaSequencer) = 0;
         virtual void Activate() = 0;
         virtual void Deactivate() = 0;

src/AudioHost.cpp

@@ -18,6 +18,7 @@
 // IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 // CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+#include "PiPedalCommon.hpp"
 #include "AudioHost.hpp"
 #include "util.hpp"
 #include <lv2/atom/atom.h>
@@ -519,12 +520,17 @@ private:
     SystemMidiBinding rebootMidiBinding;
     SystemMidiBinding shutdownMidiBinding;
 
-    JackChannelSelection channelSelection;
+    ChannelSelection channelSelection;
     std::atomic<bool> active = false;
     std::atomic<bool> audioStopped = false;
     std::atomic<bool> isDummyAudioDriver = false;
 
     std::shared_ptr<Lv2Pedalboard> currentPedalboard;
+    std::shared_ptr<Lv2Pedalboard> currentMainInsertPedalboard;
+    std::shared_ptr<Lv2Pedalboard> currentAuxInsertPedalboard;
+
+
+
     std::vector<std::shared_ptr<Lv2Pedalboard>> activePedalboards; // pedalboards that have been sent to the audio queue.
     Lv2Pedalboard *realtimeActivePedalboard = nullptr;
 
@@ -620,9 +626,9 @@ private:
 
     void ZeroOutputBuffers(size_t nframes)
     {
-        for (size_t i = 0; i < audioDriver->OutputBufferCount(); ++i)
+        for (size_t i = 0; i < audioDriver->MainOutputBufferCount(); ++i)
         {
-            float * out = (float *)audioDriver->GetOutputBuffer(i);
+            float * out = (float *)audioDriver->GetMainOutputBuffer(i);
             if (out)
             {
                 ZeroBuffer(out, nframes);
@@ -1173,9 +1179,9 @@ private:
                 float *inputBuffers[4];
                 float *outputBuffers[4];
                 bool buffersValid = true;
-                for (int i = 0; i < audioDriver->InputBufferCount(); ++i)
+                for (int i = 0; i < audioDriver->MainInputBufferCount(); ++i)
                 {
-                    float *input = (float *)audioDriver->GetInputBuffer(i);
+                    float *input = (float *)audioDriver->GetMainInputBuffer(i);
                     if (input == nullptr)
                     {
                         buffersValid = false;
@@ -1183,11 +1189,11 @@ private:
                     }
                     inputBuffers[i] = input;
                 }
-                inputBuffers[audioDriver->InputBufferCount()] = nullptr;
+                inputBuffers[audioDriver->MainInputBufferCount()] = nullptr;
 
-                for (int i = 0; i < audioDriver->OutputBufferCount(); ++i)
+                for (int i = 0; i < audioDriver->MainOutputBufferCount(); ++i)
                 {
-                    float *output = audioDriver->GetOutputBuffer(i);
+                    float *output = audioDriver->GetMainOutputBuffer(i);
                     if (output == nullptr)
                     {
                         buffersValid = false;
@@ -1195,7 +1201,7 @@ private:
                     }
                     outputBuffers[i] = output;
                 }
-                outputBuffers[audioDriver->OutputBufferCount()] = nullptr;
+                outputBuffers[audioDriver->MainOutputBufferCount()] = nullptr;
 
                 if (buffersValid)
                 {
@@ -1670,7 +1676,7 @@ public:
         return result;
     }
 
-    virtual void Open(const JackServerSettings &jackServerSettings, const JackChannelSelection &channelSelection)
+    virtual void Open(const JackServerSettings &jackServerSettings, const ChannelSelection &channelSelection_)
     {
 
         std::lock_guard guard(mutex);
@@ -1692,11 +1698,6 @@ public:
             this->audioDriver = std::unique_ptr<AudioDriver>(CreateAlsaDriver(this));
         }
 
-        if (channelSelection.GetInputAudioPorts().size() == 0 || channelSelection.GetOutputAudioPorts().size() == 0)
-        {
-            return;
-        }
-
         this->currentSample = 0;
         this->underruns = 0;
 
@@ -1707,7 +1708,7 @@ public:
         this->realtimeReader.Reset();
         this->realtimeWriter.Reset();
 
-        this->channelSelection = channelSelection;
+        this->channelSelection = channelSelection_;
 
         StartReaderThread();
 
@@ -1795,6 +1796,7 @@ public:
         }
     }
 
+
     virtual void SetPluginPreset(uint64_t instanceId, const std::vector<ControlValue> &values)
     {
         std::lock_guard guard(mutex);
@@ -1896,6 +1898,49 @@ public:
         pendingSnapshots.clear();
     }
 
+    PIPEDAL_NON_INLINE RealtimePedalboardItemIndex GetRealtimeItemIndex(int64_t instanceId)
+    {
+        Pedalboard::InstanceType instanceType = Pedalboard::GetInstanceTypeFromInstanceId(instanceId);
+        int64_t index = -1;
+        switch (instanceType)
+        {
+            case Pedalboard::InstanceType::MainPedalboard:
+                if (this->currentPedalboard) {
+                    if (instanceId == Pedalboard::START_CONTROL_ID) {
+                        index = Pedalboard::START_CONTROL_ID; 
+                    } else if (instanceId == Pedalboard::END_CONTROL_ID) {
+                        index = Pedalboard::END_CONTROL_ID; 
+                    } else {
+                        index = this->currentPedalboard->GetIndexOfInstanceId(instanceId);
+                    }
+                }
+                break;
+            case Pedalboard::InstanceType::MainInsert:
+                if (this->currentMainInsertPedalboard) {
+                    if (instanceId == Pedalboard::MAIN_INSERT_START_CONTROL_ID) {
+                        index = Pedalboard::MAIN_INSERT_START_CONTROL_ID; 
+                    } else if (instanceId == Pedalboard::MAIN_INSERT_END_CONTROL_ID) {
+                        index = Pedalboard::END_CONTROL_ID; 
+                    } else {
+                        index = this->currentMainInsertPedalboard->GetIndexOfInstanceId(instanceId);
+                    }
+                }   
+                break;
+            case Pedalboard::InstanceType::AuxInsert:
+                if (this->currentAuxInsertPedalboard) {
+                    if (instanceId == Pedalboard::AUX_INSERT_START_CONTROL_ID) {
+                        index = Pedalboard::START_CONTROL_ID; 
+                    } else if (instanceId == Pedalboard::AUX_INSERT_END_CONTROL_ID) {
+                        index = Pedalboard::END_CONTROL_ID; 
+                    } else {
+                        index = this->currentAuxInsertPedalboard->GetIndexOfInstanceId(instanceId);
+                    }
+                }
+                break;
+        }
+        RealtimePedalboardItemIndex result { instanceType, index};
+        return result;
+    }
     virtual void SetVuSubscriptions(const std::vector<int64_t> &instanceIds)
     {
         std::lock_guard guard(mutex);
@@ -1917,7 +1962,7 @@ public:
                     auto effect = this->currentPedalboard->GetEffect(instanceId);
                     if (effect)
                     {
-                        int index = this->currentPedalboard->GetIndexOfInstanceId(instanceIds[i]);
+                        RealtimePedalboardItemIndex index = this->GetRealtimeItemIndex(instanceIds[i]);
                         vuConfig->enabledIndexes.push_back(index);
                         VuUpdate v;
                         v.instanceId_ = instanceId;
@@ -1929,20 +1974,41 @@ public:
                         vuConfig->vuUpdateWorkingData.push_back(v);
                         vuConfig->vuUpdateResponseData.push_back(v);
                     }
-                    else if (instanceId == Pedalboard::INPUT_VOLUME_ID || instanceId == Pedalboard::OUTPUT_VOLUME_ID)
+                    else if (
+                        instanceId == Pedalboard::START_CONTROL_ID || instanceId == Pedalboard::END_CONTROL_ID
+                    || instanceId == Pedalboard::MAIN_INSERT_START_CONTROL_ID || instanceId == Pedalboard::MAIN_INSERT_END_CONTROL_ID
+                    || instanceId == Pedalboard::AUX_INSERT_START_CONTROL_ID || instanceId == Pedalboard::AUX_INSERT_END_CONTROL_ID 
+                    )
                     {
-                        int index = (int)instanceId;
+                        auto index = GetRealtimeItemIndex(instanceId);
                         VuUpdate v;
                         vuConfig->enabledIndexes.push_back(index);
+                            
                         v.instanceId_ = instanceId;
-                        if (instanceId == Pedalboard::INPUT_VOLUME_ID)
+                        size_t nChannels = 0;
+
+                        switch (instanceId) 
                         {
-                            v.isStereoInput_ = v.isStereoOutput_ = this->pHost->GetNumberOfInputAudioChannels() > 1;
-                        }
-                        else
-                        {
-                            v.isStereoInput_ = v.isStereoOutput_ = this->pHost->GetNumberOfOutputAudioChannels() > 1;
+                            case Pedalboard::START_CONTROL_ID:
+                                nChannels = this->pHost->GetChannelSelection().mainInputChannels().size();
+                                break;
+                            case Pedalboard::END_CONTROL_ID:
+                                nChannels = this->pHost->GetChannelSelection().mainOutputChannels().size();
+                                break;
+                            case Pedalboard::MAIN_INSERT_START_CONTROL_ID:
+                                nChannels = this->pHost->GetChannelSelection().mainOutputChannels().size();
+                                break;
+                            case Pedalboard::MAIN_INSERT_END_CONTROL_ID:
+                                nChannels = this->pHost->GetChannelSelection().mainOutputChannels().size();
+                                break;
+                            case Pedalboard::AUX_INSERT_START_CONTROL_ID:
+                                nChannels = this->pHost->GetChannelSelection().auxInputChannels().size();
+                                break;
+                            case Pedalboard::AUX_INSERT_END_CONTROL_ID:
+                                nChannels = this->pHost->GetChannelSelection().auxOutputChannels().size();
+                                break;
                         }
+                        v.isStereoInput_ = v.isStereoOutput_ = nChannels > 1;
                         vuConfig->vuUpdateWorkingData.push_back(v);
                         vuConfig->vuUpdateResponseData.push_back(v);
                     }

src/AudioHost.hpp

@@ -32,6 +32,7 @@
 #include "Promise.hpp"
 #include "json_variant.hpp"
 #include "RealtimeMidiEventType.hpp"
+#include "ChannelRouterSettings.hpp"
 
 namespace pipedal
 {
@@ -227,7 +228,7 @@ namespace pipedal
 
         virtual std::string AtomToJson(const LV2_Atom *atom) = 0;
 
-        virtual void Open(const JackServerSettings &jackServerSettings, const JackChannelSelection &channelSelection) = 0;
+        virtual void Open(const JackServerSettings &jackServerSettings, const ChannelSelection &channelSelection) = 0;
         virtual void Close() = 0;
 
         virtual void SetAlsaSequencerConfiguration(const AlsaSequencerConfiguration &alsaSequencerConfiguration) = 0;

src/Banks.hpp

@@ -240,7 +240,7 @@ namespace pipedal
                     {
                         // zero length? We can never have a zero-length bank.
                         // Add a default preset and make it the selected preset.
-                        Pedalboard pedalboard = Pedalboard::MakeDefault();
+                        Pedalboard pedalboard = Pedalboard::MakeDefault(Pedalboard::InstanceType::MainPedalboard);
                         this->addPreset(pedalboard);
                         newSelection = presets_[0]->instanceId();
                     }

src/CMakeLists.txt

@@ -204,6 +204,7 @@ else()
 endif()
 
 set (PIPEDAL_SOURCES
+    ChannelRouterSettings.cpp ChannelRouterSettings.hpp
     CrashGuard.cpp CrashGuard.hpp
     ModTemplateGenerator.cpp ModTemplateGenerator.hpp
     WebServerMod.cpp WebServerMod.hpp

src/ChannelRouterSettings.cpp

@@ -0,0 +1,151 @@
+// Copyright (c) 2026 Robin Davies
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of
+// this software and associated documentation files (the "Software"), to deal in
+// the Software without restriction, including without limitation the rights to
+// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+// the Software, and to permit persons to whom the Software is furnished to do so,
+// subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+
+#include "ChannelRouterSettings.hpp"
+#include <stdexcept>
+
+using namespace pipedal;
+
+static uint64_t countChannels(const std::vector<int64_t> &channels)
+{
+    if (channels.size() != 2)
+    {
+        throw std::runtime_error("Invalid Channel Router channel configuration.");
+    }
+    if (channels[0] == -1)
+    {
+        if (channels[1] == -1)
+        {
+            return 0;
+        }
+        else
+        {
+            return 1;
+        }
+    }
+    else
+    {
+        if (channels[1] == -1)
+        {
+            return 1;
+        }
+        if (channels[0] == channels[1])
+        {
+            return 1;
+        }
+        return 2;
+    }
+}   
+
+uint64_t ChannelRouterSettings::numberOfAudioInputChannels() const
+{
+    if (!configured_)
+    {
+        return 2;
+    }
+    return countChannels(mainInputChannels_);
+}
+uint64_t ChannelRouterSettings::numberOfAudioOutputChannels() const
+{
+    if (!configured_)
+    {
+        return 2;
+    }
+    return countChannels(mainOutputChannels_);
+}
+
+ChannelSelection::ChannelSelection(ChannelRouterSettings&settings)
+: mainInputChannels_(settings.mainInputChannels())
+, mainOutputChannels_(settings.mainOutputChannels())
+, auxInputChannels_(settings.auxInputChannels())
+, auxOutputChannels_(settings.auxOutputChannels())
+, sendInputChannels_(settings.sendInputChannels())
+, sendOutputChannels_(settings.sendOutputChannels())
+{
+    normalizeChannelSelection(); 
+}
+
+static void normalizeInputChannels(std::vector<int64_t>&channels) {
+    if (channels.size() == 2) {
+        if (channels[0] == -1 && channels[1] == -1) 
+        {
+            channels.resize(0);
+        } else if (channels[0] == channels[1]) {
+            channels.resize(1);
+        } else if (channels[1] == -1) {
+            channels.resize(1);} {
+        }
+    }
+}
+
+static void normalizeOutputChannels(std::vector<int64_t>&channels) {
+    normalizeInputChannels(channels);
+}
+
+void ChannelSelection::normalizeChannelSelection() {
+    normalizeInputChannels(mainInputChannels_);
+    normalizeOutputChannels(mainOutputChannels_);
+    normalizeInputChannels(auxInputChannels_);
+    normalizeOutputChannels(auxOutputChannels_);
+    normalizeInputChannels(sendInputChannels_);
+    normalizeOutputChannels(sendOutputChannels_);
+
+    // If either aux inputs or outputs are zero, don't do ANY aux processing.
+    if (auxInputChannels_.size() == 0) 
+    {
+        auxOutputChannels_.resize(0);
+    } else if (auxOutputChannels_.size() == 0) {
+        auxInputChannels_.resize(0);
+    }
+    // If either main inputs or outputs are empty, add send/receive dummy buffers. (Lv2 plugins shouldn't have to deal with this)
+    if (mainInputChannels_.size() == 0) 
+    {
+        mainInputChannels_.resize(1);
+        mainInputChannels_[0] = -1;
+    }
+    if (mainOutputChannels_.size() == 0) {
+        mainInputChannels_.resize(1);
+        mainOutputChannels_[0] = -1;
+    }
+    // Send buffers are what they are. Let the send plugin deal with it. 
+}
+
+
+ChannelRouterSettings::ChannelRouterSettings()
+: mainInserts_(Pedalboard::InstanceType::MainInsert)
+, auxInserts_(Pedalboard::InstanceType::AuxInsert)
+{
+    
+}
+
+
+JSON_MAP_BEGIN(ChannelRouterSettings)
+JSON_MAP_REFERENCE(ChannelRouterSettings, configured)
+JSON_MAP_REFERENCE(ChannelRouterSettings, channelRouterPresetId)
+JSON_MAP_REFERENCE(ChannelRouterSettings, mainInputChannels)
+JSON_MAP_REFERENCE(ChannelRouterSettings, mainOutputChannels)
+JSON_MAP_REFERENCE(ChannelRouterSettings, mainInserts)
+JSON_MAP_REFERENCE(ChannelRouterSettings, auxInputChannels)
+JSON_MAP_REFERENCE(ChannelRouterSettings, auxOutputChannels)
+JSON_MAP_REFERENCE(ChannelRouterSettings, auxInserts)
+JSON_MAP_REFERENCE(ChannelRouterSettings, sendInputChannels)
+JSON_MAP_REFERENCE(ChannelRouterSettings, sendOutputChannels)   
+JSON_MAP_REFERENCE(ChannelRouterSettings, controlValues)
+JSON_MAP_END()

src/ChannelRouterSettings.hpp

@@ -0,0 +1,107 @@
+// Copyright (c) 2026 Robin Davies
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of
+// this software and associated documentation files (the "Software"), to deal in
+// the Software without restriction, including without limitation the rights to
+// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+// the Software, and to permit persons to whom the Software is furnished to do so,
+// subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+#pragma once
+
+#include <vector>
+#include "json.hpp"
+#include "Pedalboard.hpp"
+#include <memory>
+
+namespace pipedal
+{
+
+    class ChannelRouterSettings
+    {
+    protected:
+        static constexpr int64_t CHANNEL_ROUTER_MAIN_INSERT_ID = -4; // Reserved Instance ID for Router Main Inserts.
+        static constexpr int64_t CHANNEL_ROUTER_AUX_INSERT_ID = -5;  // Reserved Instance ID for Router Aux inserts.
+
+        bool configured_ = false;
+        int64_t channelRouterPresetId_ = -1;
+
+        std::vector<int64_t> mainInputChannels_ = {1, 1};
+        std::vector<int64_t> mainOutputChannels_ = {0, 1};
+        Pedalboard mainInserts_;
+
+        std::vector<int64_t> auxInputChannels_ = {-1, -1};
+        std::vector<int64_t> auxOutputChannels_ = {-1, -1};
+        Pedalboard auxInserts_;
+
+        std::vector<int64_t> sendInputChannels_ = {-1, -1};
+        std::vector<int64_t> sendOutputChannels_ = {-1, -1};
+
+        std::vector<ControlValue> controlValues_;
+
+    public: 
+        using self = ChannelRouterSettings;
+        using ptr = std::shared_ptr<self>;
+
+        ChannelRouterSettings();
+
+        uint64_t numberOfAudioInputChannels() const;
+        uint64_t numberOfAudioOutputChannels() const;
+        
+        JSON_GETTER_SETTER(configured)
+        JSON_GETTER_SETTER(channelRouterPresetId)
+        JSON_GETTER_SETTER_REF(mainInputChannels)
+        JSON_GETTER_SETTER_REF(mainOutputChannels)
+        JSON_GETTER_SETTER_REF(mainInserts)
+        JSON_GETTER_SETTER_REF(auxInputChannels)
+        JSON_GETTER_SETTER_REF(auxOutputChannels)
+        JSON_GETTER_SETTER_REF(auxInserts)
+        JSON_GETTER_SETTER_REF(sendInputChannels)
+        JSON_GETTER_SETTER_REF(sendOutputChannels)
+        JSON_GETTER_SETTER_REF(controlValues)
+
+
+        DECLARE_JSON_MAP(ChannelRouterSettings);
+
+    };
+
+        // just the channel selecttions.
+    class ChannelSelection {
+    public:
+        ChannelSelection() = default;
+        ChannelSelection(ChannelRouterSettings&settings);
+        ChannelSelection(const ChannelSelection&other) = default;
+        ChannelSelection(ChannelSelection&&other) = default;
+        ChannelSelection& operator=(const ChannelSelection&other) = default;
+        ChannelSelection& operator=(ChannelSelection&&other) = default;
+        ~ChannelSelection() = default;
+
+        const std::vector<int64_t>&mainInputChannels() const { return mainInputChannels_; }
+        const std::vector<int64_t>&mainOutputChannels() const { return mainOutputChannels_; }
+        const std::vector<int64_t>&auxInputChannels() const { return auxInputChannels_; }
+        const std::vector<int64_t>&auxOutputChannels() const { return auxOutputChannels_; }
+        const std::vector<int64_t>&sendInputChannels() const { return sendInputChannels_; }
+        const std::vector<int64_t>&sendOutputChannels() const { return sendOutputChannels_; }    
+
+    private:
+        void normalizeChannelSelection();
+
+        std::vector<int64_t> mainInputChannels_;
+        std::vector<int64_t> mainOutputChannels_;
+        std::vector<int64_t> auxInputChannels_;
+        std::vector<int64_t> auxOutputChannels_;
+        std::vector<int64_t> sendInputChannels_;
+        std::vector<int64_t> sendOutputChannels_;
+    };
+
+}

src/DummyAudioDriver.cpp

@@ -1,7 +1,7 @@
 /*
  * MIT License
  *
- * Copyright (c) 2024 Robin E. R. Davies
+ * Copyright (c) 2026 Robin E. R. Davies
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy of
  * this software and associated documentation files (the "Software"), to deal in
@@ -23,6 +23,7 @@
  */
 
 #include "pch.h"
+#include "PiPedalCommon.hpp"
 #include "util.hpp"
 #include <bit>
 #include <memory>
@@ -39,6 +40,7 @@
 #include "ss.hpp"
 #include "SchedulerPriority.hpp"
 #include "CrashGuard.hpp"
+#include "ChannelRouterSettings.hpp"
 
 #include "CpuUse.hpp"
 
@@ -85,14 +87,19 @@ namespace pipedal
         uint32_t captureFrameSize = 0;
 
 
-        std::vector<float *> activeCaptureBuffers;
-        std::vector<float *> activePlaybackBuffers;
+        std::vector<std::vector<float>> allocatedBuffers;
+        std::vector<float *> mainCaptureBuffers;
+        std::vector<float *> mainPlaybackBuffers;
 
-        std::vector<float *> captureBuffers;
-        std::vector<float *> playbackBuffers;
+        std::vector<float *> auxCaptureBuffers;
+        std::vector<float *> auxPlaybackBuffers;
+
+        std::vector<float*> sendCaptureBuffers;
+        std::vector<float*> sendPlaybackBuffers;
+
+        std::vector<float *> deviceCaptureBuffers;
+        std::vector<float *> devicePlaybackBuffers;
 
-        uint8_t *rawCaptureBuffer = nullptr;
-        uint8_t *rawPlaybackBuffer = nullptr;
 
         AudioDriverHost *driverHost = nullptr;
         uint32_t channels = 2;
@@ -145,7 +152,7 @@ namespace pipedal
 
         std::atomic<bool> terminateAudio_ = false;
 
-        void terminateAudio(bool terminate)
+        PIPEDAL_NON_INLINE void terminateAudio(bool terminate)
         {
             this->terminateAudio_ = terminate;
         }
@@ -161,32 +168,28 @@ namespace pipedal
         }
 
     private:
-        void AllocateBuffers(std::vector<float *> &buffers, size_t n)
+        PIPEDAL_NON_INLINE void AllocateBuffers(std::vector<float *> &buffers, size_t n)
         {
             buffers.resize(n);
             for (size_t i = 0; i < n; ++i)
             {
-                buffers[i] = new float[this->bufferSize];
-                for (size_t j = 0; j < this->bufferSize; ++j)
-                {
-                    buffers[i][j] = 0;
-                }
+                buffers[i] = AllocateAudioBuffer();
             }
         }
 
-        virtual size_t GetMidiInputEventCount() override
+        PIPEDAL_NON_INLINE virtual size_t GetMidiInputEventCount() override
         {
             return midiEventCount;
         }
-        virtual MidiEvent *GetMidiEvents() override
+        PIPEDAL_NON_INLINE virtual MidiEvent *GetMidiEvents() override
         {
             return this->midiEvents.data();
         }
 
 
-        JackChannelSelection channelSelection;
+        ChannelSelection channelSelection;
         bool open = false;
-        virtual void Open(const JackServerSettings &jackServerSettings, const JackChannelSelection &channelSelection)
+        PIPEDAL_NON_INLINE virtual void Open(const JackServerSettings &jackServerSettings, const ChannelSelection &channelSelection)
         {
             terminateAudio_ = false;
             if (open)
@@ -208,7 +211,7 @@ namespace pipedal
                 throw;
             }
         }
-        virtual void SetAlsaSequencer(AlsaSequencer::ptr alsaSequencer) override
+        PIPEDAL_NON_INLINE virtual void SetAlsaSequencer(AlsaSequencer::ptr alsaSequencer) override
         {
             this->alsaSequencer = alsaSequencer;
         }
@@ -220,23 +223,28 @@ namespace pipedal
                 << ", " << "Native float"
                 << ", " << this->sampleRate
                 << ", " << this->bufferSize << "x" << this->numberOfBuffers
-                << ", in: " << this->InputBufferCount() << "/" << this->captureChannels
-                << ", out: " << this->OutputBufferCount() << "/" << this->playbackChannels);
+                << ", " << "device in: " << this->DeviceInputBufferCount() 
+                << ", " << "device out: " << this->DeviceOutputBufferCount()
+                << ", main in: " << this->MainInputBufferCount() 
+                << ", main out: " << this->MainOutputBufferCount() 
+                << ", aux in: " << this->AuxInputBufferCount() 
+                << ", aux out: " << this->AuxOutputBufferCount()
+                << ", send in: " << this->SendInputBufferCount() 
+                << ", send out: " << this->SendOutputBufferCount()
+            );
             return result;
         }
 
-        void OpenAudio(const JackServerSettings &jackServerSettings, const JackChannelSelection &channelSelection)
+        void OpenAudio(const JackServerSettings &jackServerSettings, const ChannelSelection &channelSelection)
         {
             int err;
 
             this->numberOfBuffers = jackServerSettings.GetNumberOfBuffers();
             this->bufferSize = jackServerSettings.GetBufferSize();
-            AllocateBuffers(captureBuffers, channels);
-            AllocateBuffers(playbackBuffers, channels);
      
         }
 
-        std::jthread *audioThread;
+        std::unique_ptr<std::jthread> audioThread;
         bool audioRunning;
 
         bool block = false;
@@ -303,7 +311,7 @@ namespace pipedal
                     this->driverHost->OnProcess(framesRead);
 
                     /// no attempt at realtime. Just as long as we run occasionally.
-                    std::this_thread::sleep_for(std::chrono::milliseconds(20));
+                    std::this_thread::sleep_for(std::chrono::milliseconds(5));
 
 
                 }
@@ -318,22 +326,6 @@ namespace pipedal
 
         bool alsaActive = false;
 
-        static int IndexFromPortName(const std::string &s)
-        {
-            auto pos = s.find_last_of('_');
-            if (pos == std::string::npos)
-            {
-                throw std::invalid_argument("Bad port name.");
-            }
-            const char *p = s.c_str() + (pos + 1);
-
-            int v = atoi(p);
-            if (v < 0)
-            {
-                throw std::invalid_argument("Bad port name.");
-            }
-            return v;
-        }
 
         bool activated = false;
         virtual void Activate()
@@ -344,41 +336,17 @@ namespace pipedal
             }
             activated = true;
 
-            this->activeCaptureBuffers.resize(channelSelection.GetInputAudioPorts().size());
+            AllocateBuffers(deviceCaptureBuffers, channels);
+            AllocateBuffers(devicePlaybackBuffers, channels);
 
-            playbackBuffers.resize(channels);
+            AllocateBuffers(mainCaptureBuffers, channelSelection.mainInputChannels().size());
+            AllocateBuffers(mainPlaybackBuffers, channelSelection.mainOutputChannels().size());
+            AllocateBuffers(auxCaptureBuffers, channelSelection.auxInputChannels().size());
+            AllocateBuffers(auxPlaybackBuffers, channelSelection.auxOutputChannels().size());
+            AllocateBuffers(sendCaptureBuffers, channelSelection.sendInputChannels().size());
+            AllocateBuffers(sendPlaybackBuffers, channelSelection.sendOutputChannels().size());
 
-            int ix = 0;
-            for (auto &x : channelSelection.GetInputAudioPorts())
-            {
-                int sourceIndex = IndexFromPortName(x);
-                if (sourceIndex >= captureBuffers.size())
-                {
-                    Lv2Log::error(SS("Invalid audio input port: " << x));
-                }
-                else
-                {
-                    this->activeCaptureBuffers[ix++] = this->captureBuffers[sourceIndex];
-                }
-            }
-
-            this->activePlaybackBuffers.resize(channelSelection.GetOutputAudioPorts().size());
-
-            ix = 0;
-            for (auto &x : channelSelection.GetOutputAudioPorts())
-            {
-                int sourceIndex = IndexFromPortName(x);
-                if (sourceIndex >= playbackBuffers.size())
-                {
-                    Lv2Log::error(SS("Invalid audio output port: " << x));
-                }
-                else
-                {
-                    this->activePlaybackBuffers[ix++] = this->playbackBuffers[sourceIndex];
-                }
-            }
-
-            audioThread = new std::jthread([this]()
+            audioThread = std::make_unique<std::jthread>([this]()
                                            { AudioThread(); });
         }
 
@@ -393,7 +361,7 @@ namespace pipedal
             if (audioThread)
             {
                 this->audioThread->join();
-                this->audioThread = 0;
+                this->audioThread = nullptr;
             }
             Lv2Log::debug("Audio thread joined.");
         }
@@ -402,46 +370,64 @@ namespace pipedal
     public:
 
 
+        virtual size_t DeviceInputBufferCount() const override { return deviceCaptureBuffers.size(); }
+        virtual size_t DeviceOutputBufferCount() const override { return devicePlaybackBuffers.size(); }
    
-        virtual size_t InputBufferCount() const { return activeCaptureBuffers.size(); }
-        virtual float *GetInputBuffer(size_t channel)
+        virtual size_t MainInputBufferCount() const override { return mainCaptureBuffers.size(); }
+        virtual float *GetMainInputBuffer(size_t channel) override
         {
-            return activeCaptureBuffers[channel];
+            return mainCaptureBuffers[channel];
         }
 
-        virtual size_t OutputBufferCount() const { return activePlaybackBuffers.size(); }
-        virtual float *GetOutputBuffer(size_t channel)
+        virtual size_t MainOutputBufferCount() const { return mainPlaybackBuffers.size(); }
+        virtual float *GetMainOutputBuffer(size_t channel) override
         {
-            return activePlaybackBuffers[channel];
+            return mainPlaybackBuffers[channel];
         }
 
-        void FreeBuffers(std::vector<float *> &buffer)
+        virtual size_t AuxInputBufferCount() const override { return auxCaptureBuffers.size(); }
+        virtual float *GetAuxInputBuffer(size_t channel) override
         {
-            for (size_t i = 0; i < buffer.size(); ++i)
-            {
-                // delete[] buffer[i];
-                buffer[i] = 0;
-            }
-            buffer.clear();
+            return auxCaptureBuffers[channel];
         }
-        void DeleteBuffers()
+
+        virtual size_t AuxOutputBufferCount() const override { return auxPlaybackBuffers.size(); }
+        virtual float *GetAuxOutputBuffer(size_t channel) override
         {
-            activeCaptureBuffers.clear();
-            activePlaybackBuffers.clear();
-            FreeBuffers(this->playbackBuffers);
-            FreeBuffers(this->captureBuffers);
-            if (rawCaptureBuffer)
-            {
-                delete[] rawCaptureBuffer;
-                rawCaptureBuffer = nullptr;
-            }
-            if (rawPlaybackBuffer)
-            {
-                delete[] rawPlaybackBuffer;
-                rawPlaybackBuffer = nullptr;
-            }
+            return auxPlaybackBuffers[channel];
         }
-        virtual void Close()
+
+        virtual size_t SendInputBufferCount() const override { return sendCaptureBuffers.size(); }
+        virtual float *GetSendInputBuffer(size_t channel) override
+        {
+            return sendCaptureBuffers[channel];
+        }
+
+        virtual size_t SendOutputBufferCount() const override { return sendPlaybackBuffers.size(); }
+        virtual float *GetSendOutputBuffer(size_t channel) override
+        {
+            return sendPlaybackBuffers[channel];
+        }
+
+
+
+        
+
+        PIPEDAL_NON_INLINE float*AllocateAudioBuffer() {
+            allocatedBuffers.push_back(std::vector<float>(bufferSize));
+            return allocatedBuffers.back().data();
+        }
+        PIPEDAL_NON_INLINE void DeleteBuffers()
+        {
+            mainCaptureBuffers.clear();
+            mainPlaybackBuffers.clear();
+            auxCaptureBuffers.clear();
+            auxPlaybackBuffers.clear();
+            sendCaptureBuffers.clear();
+            sendPlaybackBuffers.clear();
+            allocatedBuffers.clear();
+        }
+        PIPEDAL_NON_INLINE virtual void Close()
         {
             if (!open)
             {
@@ -453,18 +439,18 @@ namespace pipedal
             DeleteBuffers();
         }
 
-        virtual float CpuUse()
+        PIPEDAL_NON_INLINE virtual float CpuUse()
         {
             return 0;
         }
 
-        virtual float CpuOverhead()
+        PIPEDAL_NON_INLINE virtual float CpuOverhead()
         {
             return 0.1;
         }
     };
 
-    AudioDriver *CreateDummyAudioDriver(AudioDriverHost *driverHost,const std::string&deviceName)
+    PIPEDAL_NON_INLINE AudioDriver *CreateDummyAudioDriver(AudioDriverHost *driverHost,const std::string&deviceName)
     {
         return new DummyDriverImpl(driverHost,deviceName);
     }

src/IHost.hpp

@@ -26,6 +26,7 @@ namespace pipedal {
     class Lv2PluginInfo;
     class IEffect;
     class HostWorkerThread;
+    class ChannelSelection;
 
     class IHost
     {
@@ -43,13 +44,12 @@ namespace pipedal {
         virtual size_t GetAtomBufferSize() const = 0;
 
         virtual bool HasMidiInputChannel() const = 0;
-        virtual int GetNumberOfInputAudioChannels() const = 0;
-        virtual int GetNumberOfOutputAudioChannels() const = 0;
         virtual std::shared_ptr<Lv2PluginInfo> GetPluginInfo(const std::string &uri) const = 0;
 
         virtual IEffect *CreateEffect(PedalboardItem &pedalboard) = 0;
 
         virtual std::string GetPluginStoragePath() const = 0;
+        virtual const ChannelSelection&GetChannelSelection() const = 0;
 
     };
 }

src/JackConfiguration.hpp

@@ -124,5 +124,4 @@ namespace pipedal
         DECLARE_JSON_MAP(JackChannelSelection);
     };
 
-
 } // namespace.

src/Lv2Pedalboard.cpp

@@ -574,7 +574,7 @@ void Lv2Pedalboard::ComputeVus(RealtimeVuBuffers *vuConfiguration, uint32_t samp
     {
         int index = vuConfiguration->enabledIndexes[i];
         VuUpdate *pUpdate = &vuConfiguration->vuUpdateWorkingData[i];
-        if (index == Pedalboard::INPUT_VOLUME_ID)
+        if (index == Pedalboard::START_CONTROL_ID)
         {
             if (this->pedalboardInputBuffers.size() > 1)
             {
@@ -588,7 +588,7 @@ void Lv2Pedalboard::ComputeVus(RealtimeVuBuffers *vuConfiguration, uint32_t samp
                 pUpdate->AccumulateOutputs(&(this->pedalboardInputBuffers[0][0]), samples); // after input volume applied.
             }
         }
-        else if (index == Pedalboard::OUTPUT_VOLUME_ID)
+        else if (index == Pedalboard::END_CONTROL_ID)
         {
             if (this->pedalboardOutputBuffers.size() > 1)
             {

src/Pedalboard.cpp

@@ -210,7 +210,7 @@ PedalboardItem Pedalboard::MakeSplit()
 
 
 
-Pedalboard Pedalboard::MakeDefault()
+Pedalboard Pedalboard::MakeDefault(InstanceType instanceType)
 {
     // copy insanity. but it happens so rarely.
     Pedalboard result;
@@ -510,6 +510,22 @@ Snapshot Pedalboard::MakeSnapshotFromCurrentSettings(const Pedalboard &previousP
 }
 
 
+Pedalboard::Pedalboard(InstanceType instanceType = InstanceType::MainPedalboard)
+{
+    switch (instanceType) 
+    {
+        case InstanceType::MainPedalboard:
+            nextInstanceId_ = 0;
+            break;
+        case InstanceType::MainInsert:
+            nextInstanceId_ = MAIN_INSERT_INSTANCE_BASE;;
+            break;
+        case InstanceType::AuxInsert:
+            nextInstanceId_ = AUX_INSERT_INSTANCE_BASE;;
+            break;
+    }
+}
+
 
 JSON_MAP_BEGIN(ControlValue)
     JSON_MAP_REFERENCE(ControlValue,key)

src/Pedalboard.hpp

@@ -230,11 +230,52 @@ class Pedalboard {
 
     int64_t selectedPlugin_ = -1;
 
+    static constexpr int64_t TWO_POWER_52 = 4503599627370496; // Maximum Javascript integer value.
+    static constexpr int64_t TWO_POWER_48 = 281474976710656; // Number of possible instance IDs for Main Pedalboards.
+    static constexpr int64_t MAX_INSTANCE_ID = TWO_POWER_48;
+
 public:
+
+    enum class InstanceType {
+        MainPedalboard,
+        MainInsert,
+        AuxInsert
+    };
+    static constexpr int64_t MAIN_INSERT_INSTANCE_BASE = TWO_POWER_52-2*MAX_INSTANCE_ID;
+    static constexpr int64_t  AUX_INSERT_INSTANCE_BASE = TWO_POWER_52-1*MAX_INSTANCE_ID;
+
+    static constexpr int64_t  CHANNEL_ROUTER_CONTROLS_INSTANCE_ID = -4; // Reserved Instance ID for Router Controls.
+
+    static constexpr int64_t START_CONTROL_ID = -2; // synthetic PedalboardItem for input volume.
+    static constexpr int64_t END_CONTROL_ID = -3; // synthetic PedalboardItem for output volume.
+    static constexpr int64_t MAIN_INSERT_START_CONTROL_ID = MAIN_INSERT_INSTANCE_BASE + MAX_INSTANCE_ID -2;
+    static constexpr int64_t MAIN_INSERT_END_CONTROL_ID = MAIN_INSERT_INSTANCE_BASE + MAX_INSTANCE_ID -3;
+    static constexpr int64_t AUX_INSERT_START_CONTROL_ID = AUX_INSERT_INSTANCE_BASE + MAX_INSTANCE_ID -2;
+    static constexpr int64_t AUX_INSERT_END_CONTROL_ID = AUX_INSERT_INSTANCE_BASE + MAX_INSTANCE_ID -3;
+
+    static InstanceType GetInstanceTypeFromInstanceId(int64_t instanceId) { 
+        if (instanceId == START_CONTROL_ID) return InstanceType::MainPedalboard;
+        if (instanceId == END_CONTROL_ID) return InstanceType::MainPedalboard;
+
+        if (instanceId >= MAIN_INSERT_INSTANCE_BASE) {
+            return InstanceType::MainInsert;
+        } else if (instanceId >= AUX_INSERT_INSTANCE_BASE) {
+            return InstanceType::AuxInsert;
+        } else {
+            return InstanceType::MainPedalboard;
+        }
+    }
+    InstanceType GetInstanceType() const {
+        return GetInstanceTypeFromInstanceId(this->nextInstanceId_); // instanceId is irrelevant here.
+    }   
+
+
+
+    Pedalboard(InstanceType instanceType = InstanceType::MainPedalboard);
+
     // deep copy, breaking shared pointers.
     Pedalboard DeepCopy(); 
-    static constexpr int64_t INPUT_VOLUME_ID = -2; // synthetic PedalboardItem for input volume.
-    static constexpr int64_t OUTPUT_VOLUME_ID = -3; // synthetic PedalboardItem for output volume.
+    
     bool SetControlValue(int64_t pedalItemId, const std::string &symbol, float value);
     bool SetItemTitle(int64_t pedalItemId, const std::string &title, const std::string&iconColor);
     bool SetItemEnabled(int64_t pedalItemId, bool enabled);
@@ -266,7 +307,7 @@ public:
     PedalboardItem MakeSplit();
 
 
-    static Pedalboard MakeDefault();
+    static Pedalboard MakeDefault(Pedalboard::InstanceType instanceType);
 };
 
 #undef GETTER_SETTER_REF

src/PiLatencyMain.cpp

@@ -364,16 +364,16 @@ public:
     virtual void OnProcess(size_t nFrames)
     {
 
-        size_t inputs = audioDriver->InputBufferCount();
-        size_t outputs = audioDriver->OutputBufferCount();
+        size_t inputs = audioDriver->MainInputBufferCount();
+        size_t outputs = audioDriver->MainOutputBufferCount();
 
         for (size_t i = 0; i < inputs; ++i)
         {
-            inputBuffers[i] = audioDriver->GetInputBuffer(i);
+            inputBuffers[i] = audioDriver->GetMainInputBuffer(i);
         }
         for (size_t i = 0; i < outputs; ++i)
         {
-            outputBuffers[i] = audioDriver->GetOutputBuffer(i);
+            outputBuffers[i] = audioDriver->GetMainOutputBuffer(i);
         }
 
         for (size_t i = 0; i < nFrames; ++i)

src/PiPedalCommon.hpp

@@ -0,0 +1,32 @@
+// Copyright (c) 2026 Robin Davies
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of
+// this software and associated documentation files (the "Software"), to deal in
+// the Software without restriction, including without limitation the rights to
+// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+// the Software, and to permit persons to whom the Software is furnished to do so,
+// subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+
+
+#pragma once 
+
+#ifndef PIPEDAL_NON_INLINE
+#if defined(__GNUC__) || defined(__clang__)
+#define PIPEDAL_NON_INLINE __attribute__((noinline))
+#elif defined(_MSC_VER)
+#define PIPEDAL_NON_INLINE __declspec(noinline)
+#else
+#define PIPEDAL_NON_INLINE
+#endif
+#endif

src/PiPedalModel.cpp

@@ -81,7 +81,7 @@ PiPedalModel::PiPedalModel()
     this->updater = Updater::Create();
     this->updater->Start();
     this->currentUpdateStatus = updater->GetCurrentStatus();
-    this->pedalboard = Pedalboard::MakeDefault();
+    this->pedalboard = Pedalboard::MakeDefault(Pedalboard::InstanceType::MainPedalboard);
 #if JACK_HOST
     this->jackServerSettings = this->storage.GetJackServerSettings(); // to get onboarding flag.
     this->jackServerSettings.ReadJackDaemonConfiguration();
@@ -216,6 +216,7 @@ void PiPedalModel::Init(const PiPedalConfiguration &configuration)
     storage.Initialize();
     pluginHost.SetPluginStoragePath(storage.GetPluginUploadDirectory());
 
+    this->channelRouterSettings = storage.GetChannelRouterSettings();
     this->systemMidiBindings = storage.GetSystemMidiBindings();
 
 #if JACK_HOST
@@ -298,7 +299,7 @@ void PiPedalModel::Load()
     if (CrashGuard::HasCrashed())
     {
         // ignore the current preset, and load a blank pedalboard in order to avoid a potential plugin crash.
-        this->pedalboard = Pedalboard::MakeDefault();
+        this->pedalboard = Pedalboard::MakeDefault(Pedalboard::InstanceType::MainPedalboard);
     }
     else
     {
@@ -1422,12 +1423,8 @@ void PiPedalModel::RestartAudio(bool useDummyAudioDriver)
             throw std::runtime_error("Audio configuration not valid.");
         }
 
-        auto channelSelection = this->storage.GetJackChannelSelection(jackConfiguration);
+        const auto & channelSelection = this->storage.GetChannelSelection();
 
-        if (!channelSelection.isValid())
-        {
-            throw std::runtime_error("Audio configuration not valid.");
-        }
         this->audioHost->Open(jackServerSettings, channelSelection);
 
         this->pluginHost.OnConfigurationChanged(jackConfiguration, channelSelection);
@@ -1528,21 +1525,6 @@ std::vector<AlsaSequencerPortSelection> PiPedalModel::GetAlsaSequencerPorts()
     return result;
 }
 
-void PiPedalModel::SetJackChannelSelection(int64_t clientId, const JackChannelSelection &channelSelection)
-{
-    {
-        std::lock_guard<std::recursive_mutex> lock(mutex); // copy atomically.
-        this->storage.SetJackChannelSelection(channelSelection);
-
-        this->pluginHost.OnConfigurationChanged(jackConfiguration, channelSelection);
-
-        CancelAudioRetry();
-    }
-
-    RestartAudio(); // no lock to avoid mutex deadlock when reader thread is sending notifications..
-
-    this->FireChannelSelectionChanged(clientId);
-}
 
 void PiPedalModel::FireChannelSelectionChanged(int64_t clientId)
 {
@@ -1671,7 +1653,7 @@ void PiPedalModel::UpdateRealtimeVuSubscriptions()
     for (int i = 0; i < activeVuSubscriptions.size(); ++i)
     {
         auto instanceId = activeVuSubscriptions[i].instanceid;
-        if (pedalboard.HasItem(instanceId) || instanceId == Pedalboard::INPUT_VOLUME_ID || instanceId == Pedalboard::OUTPUT_VOLUME_ID)
+        if (pedalboard.HasItem(instanceId) || instanceId == Pedalboard::START_CONTROL_ID || instanceId == Pedalboard::END_CONTROL_ID)
         {
             addedInstances.insert(activeVuSubscriptions[i].instanceid);
         }
@@ -3330,3 +3312,27 @@ int64_t PiPedalModel::CopyPresetsToBank(int64_t bankInstanceId, const std::vecto
     return lastAdded;
 
 }
+
+
+ChannelRouterSettings::ptr PiPedalModel::GetChannelRouterSettings()
+{
+    std::lock_guard<std::recursive_mutex> lock(mutex);
+    return this->channelRouterSettings;
+}
+
+void PiPedalModel::SetChannelRouterSettings(int64_t clientId,ChannelRouterSettings::ptr &settings)
+{
+    {
+        std::lock_guard<std::recursive_mutex> lock(mutex);
+        this->channelRouterSettings = settings;
+        this->storage.SetChannelRouterSettings(settings);
+        this->pluginHost.OnConfigurationChanged(jackConfiguration, *settings);
+        CancelAudioRetry();
+    }
+    RestartAudio(); // no lock to avoid mutex deadlock when reader thread is sending notifications..
+
+    this->FireChannelSelectionChanged(clientId);
+
+}
+
+

src/PiPedalModel.hpp

@@ -40,6 +40,7 @@
 #include "Promise.hpp"
 #include "AtomConverter.hpp"
 #include "FileEntry.hpp"
+#include "ChannelRouterSettings.hpp"
 #include <unordered_map>
 
 namespace pipedal
@@ -176,6 +177,8 @@ namespace pipedal
         AtomConverter atomConverter; // must be AFTER pluginHost!
 
         Pedalboard pedalboard;
+        ChannelRouterSettings::ptr channelRouterSettings;
+
         bool previousPedalboardLoaded = false;
         Pedalboard previousPedalboard;
         Storage storage;
@@ -397,7 +400,6 @@ namespace pipedal
 
         JackConfiguration GetJackConfiguration();
 
-        void SetJackChannelSelection(int64_t clientId, const JackChannelSelection &channelSelection);
         JackChannelSelection GetJackChannelSelection();
 
         void SetAlsaSequencerConfiguration(const AlsaSequencerConfiguration &alsaSequencerConfiguration);
@@ -497,6 +499,9 @@ namespace pipedal
         std::vector<PresetIndexEntry> RequestBankPresets(int64_t bankInstanceId);
         int64_t ImportPresetsFromBank(int64_t bankInstanceId, const std::vector<int64_t> &presets);
         int64_t CopyPresetsToBank(int64_t bankInstanceId, const std::vector<int64_t> &presets);
+
+        void SetChannelRouterSettings(int64_t clientId, ChannelRouterSettings::ptr &settings);
+        ChannelRouterSettings::ptr GetChannelRouterSettings();
     };
 
 } // namespace pipedal.

src/PiPedalSocket.cpp

@@ -1,4 +1,4 @@
-// Copyright (c) 2022-2023 Robin Davies
+// Copyright (c) 2026 Robin Davies
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy of
 // this software and associated documentation files (the "Software"), to deal in
@@ -1422,12 +1422,6 @@ public:
             this->model.AddNotificationSubscription(shared_from_this());
             Reply(replyTo, "ehlo", clientId);
         }
-        else if (message == "setJackSettings")
-        {
-            JackChannelSelection jackSettings;
-            pReader->read(&jackSettings);
-            this->model.SetJackChannelSelection(this->clientId, jackSettings);
-        }
         else if (message == "setShowStatusMonitor")
         {
             bool showStatusMonitor;
@@ -1847,6 +1841,14 @@ public:
             pReader->read(&args);
             auto result = this->model.CopyPresetsToBank(args.bankInstanceId_, args.presets_);
             this->Reply(replyTo,"copyPresetsToBank",result);
+        } else if (message == "getChannelRouterSettings") 
+        {
+            ChannelRouterSettings::ptr result = this->model.GetChannelRouterSettings();
+            this->Reply(replyTo, "getChannelRouterSettings", result);
+        } else if (message == "setChannelRouterSettings") {
+            ChannelRouterSettings::ptr args;
+            pReader->read(&args);
+            this->model.SetChannelRouterSettings(this->clientId, args);
         }
         else
         {

src/PluginHost.cpp

@@ -34,6 +34,7 @@
 #include "lv2/urid/urid.h"
 #include "lv2/ui/ui.h"
 #include "lv2/core/lv2.h"
+#include "ChannelRouterSettings.hpp"
 
 // #include "lv2.h"
 #include "lv2/atom/atom.h"
@@ -315,15 +316,15 @@ PluginHost::PluginHost()
     this->urids = new Urids(mapFeature);
 }
 
-void PluginHost::OnConfigurationChanged(const JackConfiguration &configuration, const JackChannelSelection &settings)
+
+void PluginHost::OnConfigurationChanged(const JackConfiguration &configuration, const ChannelSelection &channelSelection)
 {
     this->sampleRate = configuration.sampleRate();
     if (configuration.isValid())
     {
-        this->numberOfAudioInputChannels = settings.GetInputAudioPorts().size();
-        this->numberOfAudioOutputChannels = settings.GetOutputAudioPorts().size();
         this->maxBufferSize = configuration.blockLength();
     }
+    this->channelSelection = channelSelection;
 }
 
 PluginHost::~PluginHost()

src/PluginHost.hpp

@@ -43,6 +43,7 @@
 #include "PiPedalUI.hpp"
 #include "MapPathFeature.hpp"
 #include "ModGui.hpp"
+#include "ChannelRouterSettings.hpp"
 
 namespace pipedal
 {
@@ -54,6 +55,7 @@ namespace pipedal
     class PluginHost;
     class JackConfiguration;
     class JackChannelSelection;
+    class ChannelRouterSettings;
 
 #ifndef LV2_PROPERTY_GETSET
 #define LV2_PROPERTY_GETSET(name)             \
@@ -893,8 +895,8 @@ namespace pipedal
         size_t maxBufferSize = 1024;
         size_t maxAtomBufferSize = 16 * 1024;
         bool hasMidiInputChannel;
-        int numberOfAudioInputChannels = 1;
-        int numberOfAudioOutputChannels = 1;
+        ChannelSelection channelSelection;
+
         double sampleRate = 48000;
 
         std::string vst3CachePath;
@@ -955,13 +957,12 @@ namespace pipedal
 
     private:
         // IHost implementation.
-        virtual void SetMaxAudioBufferSize(size_t size) { maxBufferSize = size; }
-        virtual size_t GetMaxAudioBufferSize() const { return maxBufferSize; }
-        virtual size_t GetAtomBufferSize() const { return maxAtomBufferSize; }
-        virtual bool HasMidiInputChannel() const { return hasMidiInputChannel; }
-        virtual int GetNumberOfInputAudioChannels() const { return numberOfAudioInputChannels; }
-        virtual int GetNumberOfOutputAudioChannels() const { return numberOfAudioOutputChannels; }
-        virtual LV2_Feature *const *GetLv2Features() const { return (LV2_Feature *const *)&(this->lv2Features[0]); }
+        virtual void SetMaxAudioBufferSize(size_t size) override { maxBufferSize = size; }
+        virtual size_t GetMaxAudioBufferSize() const override { return maxBufferSize; }
+        virtual size_t GetAtomBufferSize() const override { return maxAtomBufferSize; }
+        virtual bool HasMidiInputChannel() const override  { return hasMidiInputChannel; }
+        virtual LV2_Feature *const *GetLv2Features() const override { return (LV2_Feature *const *)&(this->lv2Features[0]); }
+        virtual const ChannelSelection &GetChannelSelection() const override { return this->channelSelection; }
 
     public:
         virtual MapFeature &GetMapFeature() override { return this->mapFeature; }
@@ -1027,7 +1028,8 @@ namespace pipedal
         Urids *urids = nullptr;
         ModGuiUris *mod_gui_uris = nullptr;
 
-        void OnConfigurationChanged(const JackConfiguration &configuration, const JackChannelSelection &settings);
+        void OnConfigurationChanged(const JackConfiguration &configuration, const ChannelSelection &channelSelection);
+
 
         std::shared_ptr<Lv2PluginClass> GetPluginClass(const std::string &uri) const;
         bool is_a(const std::string &class_, const std::string &target_class);

src/RingBufferReader.hpp

@@ -96,6 +96,24 @@ namespace pipedal
 
     };
 
+    struct RealtimePedalboardItemIndex {
+        RealtimePedalboardItemIndex()
+            : instanceType(Pedalboard::InstanceType::MainPedalboard), index(-1)
+        {
+        }
+        RealtimePedalboardItemIndex(
+            Pedalboard::InstanceType instanceType,
+            int index)
+            : instanceType(instanceType), index(index)
+        {
+        }
+        RealtimePedalboardItemIndex(const RealtimePedalboardItemIndex& other) = default;
+        RealtimePedalboardItemIndex& operator=(const RealtimePedalboardItemIndex& other) = default;
+
+        Pedalboard::InstanceType instanceType = Pedalboard::InstanceType::MainPedalboard;
+        int index = -1;
+    };
+
     struct RealtimeMidiEventRequest
     {
         RealtimeMidiEventType eventType;
@@ -159,7 +177,7 @@ namespace pipedal
             return &vuUpdateResponseData;
         }
 
-        std::vector<int> enabledIndexes;
+        std::vector<RealtimePedalboardItemIndex> enabledIndexes;
         std::vector<VuUpdate> vuUpdateWorkingData;
         std::vector<VuUpdate> vuUpdateResponseData;
 

src/Storage.cpp

@@ -196,11 +196,11 @@ void Storage::SetDataRoot(const std::filesystem::path &path)
     this->dataRoot__audio_uploads = dataRoot / "audio_uploads";
 }
 
-const std::filesystem::path &Storage::GetConfigRoot()
+const std::filesystem::path &Storage::GetConfigRoot() const
 {
     return this->configRoot;
 }
-const std::filesystem::path &Storage::GetDataRoot()
+const std::filesystem::path &Storage::GetDataRoot() const
 {
     return this->dataRoot;
 }
@@ -249,7 +249,6 @@ static void removeFileNoThrow(const std::filesystem::path &path)
     }
 }
 
-
 void Storage::UpgradeFactoryPresets()
 {
     auto presetsDirectory = this->GetPresetsDirectory();
@@ -387,8 +386,10 @@ void Storage::Initialize()
 
     LoadWifiConfigSettings();
     LoadWifiDirectConfigSettings();
+    this->channelRouterSettings = LoadChannelRouterSettings();
     LoadUserSettings();
     UpgradeFactoryPresets();
+    UpgradeChannelRouterSettings();
 }
 
 void Storage::LoadBank(int64_t instanceId)
@@ -687,40 +688,46 @@ int64_t Storage::SaveCurrentPresetAs(const Pedalboard &pedalboard, int64_t bankI
     }
 }
 
-static std::string stripNumericSuffix(const std::string &name) {
+static std::string stripNumericSuffix(const std::string &name)
+{
     // remove (digit*) from the end of the string.
     // Find the last '(' character
     size_t pos = name.find_last_of('(');
-    if (pos == std::string::npos) {
+    if (pos == std::string::npos)
+    {
         return name;
     }
 
     // Check if everything between '(' and ')' is digits
-    size_t len = name.length()-1;
-    if (name[len] != ')') 
+    size_t len = name.length() - 1;
+    if (name[len] != ')')
     {
         return name;
     }
     bool allDigits = true;
-    for (size_t i = pos + 1; i < len - 1; ++i) {
-        if (name[i] < '0' || name[i] > '9') {
+    for (size_t i = pos + 1; i < len - 1; ++i)
+    {
+        if (name[i] < '0' || name[i] > '9')
+        {
             allDigits = false;
             break;
         }
     }
 
-    if (!allDigits) {
+    if (!allDigits)
+    {
         return name;
     }
 
     // Remove trailing spaces before the '('
-    while (pos > 0 && name[pos - 1] == ' ') {
+    while (pos > 0 && name[pos - 1] == ' ')
+    {
         --pos;
     }
 
     return name.substr(0, pos);
 }
-static std::string makeUniqueName(const std::string &name, const std::set<std::string>&existingNames)
+static std::string makeUniqueName(const std::string &name, const std::set<std::string> &existingNames)
 {
     if (!existingNames.contains(name))
     {
@@ -729,9 +736,11 @@ static std::string makeUniqueName(const std::string &name, const std::set<std::s
     std::string baseName = stripNumericSuffix(name);
 
     size_t i = 2;
-    while (true) {
+    while (true)
+    {
         std::string newName = SS(baseName << " (" << i << ")");
-        if (!existingNames.contains(newName)) {
+        if (!existingNames.contains(newName))
+        {
             return newName;
         }
         ++i;
@@ -739,23 +748,27 @@ static std::string makeUniqueName(const std::string &name, const std::set<std::s
 }
 int64_t Storage::ImportPresetsFromBank(int64_t bankInstanceId, const std::vector<int64_t> &presets)
 {
-    if (bankIndex.selectedBank() == bankInstanceId) {
+    if (bankIndex.selectedBank() == bankInstanceId)
+    {
         throw std::runtime_error("Can't import to self.");
     }
-    std::set<int64_t> presetsSet { presets.begin(), presets.end()};
+    std::set<int64_t> presetsSet{presets.begin(), presets.end()};
     auto indexEntry = this->bankIndex.getBankIndexEntry(bankInstanceId);
 
     std::set<std::string> existingNames;
 
-    for (auto&preset: this->currentBank.presets()) {
+    for (auto &preset : this->currentBank.presets())
+    {
         existingNames.insert(preset->preset().name());
     }
     BankFile bankFile;
-    LoadBankFile(indexEntry.name(),&bankFile);
+    LoadBankFile(indexEntry.name(), &bankFile);
     int64_t lastPresetId = -1;
-    for (auto &presetEntry: bankFile.presets()) {
-        if (presetsSet.contains(presetEntry->instanceId())) {
-            std::string uniqueName = makeUniqueName(presetEntry->preset().name(),existingNames);
+    for (auto &presetEntry : bankFile.presets())
+    {
+        if (presetsSet.contains(presetEntry->instanceId()))
+        {
+            std::string uniqueName = makeUniqueName(presetEntry->preset().name(), existingNames);
             existingNames.insert(uniqueName);
             Pedalboard t = presetEntry->preset();
             t.name(uniqueName);
@@ -767,31 +780,35 @@ int64_t Storage::ImportPresetsFromBank(int64_t bankInstanceId, const std::vector
 }
 int64_t Storage::CopyPresetsToBank(int64_t bankInstanceId, const std::vector<int64_t> &presets)
 {
-    if (bankIndex.selectedBank() == bankInstanceId) {
+    if (bankIndex.selectedBank() == bankInstanceId)
+    {
         throw std::runtime_error("Can't copy to self.");
     }
 
     auto indexEntry = this->bankIndex.getBankIndexEntry(bankInstanceId);
     BankFile bankFile;
-    LoadBankFile(indexEntry.name(),&bankFile);
+    LoadBankFile(indexEntry.name(), &bankFile);
 
-    std::set<int64_t> presetsSet { presets.begin(), presets.end()};
+    std::set<int64_t> presetsSet{presets.begin(), presets.end()};
 
     std::set<std::string> existingNames;
 
-    for (auto&preset: bankFile.presets()) {
+    for (auto &preset : bankFile.presets())
+    {
         existingNames.insert(preset->preset().name());
     }
-    for (auto &presetEntry: this->currentBank.presets()) {
-        if (presetsSet.contains(presetEntry->instanceId())) {
-            std::string uniqueName = makeUniqueName(presetEntry->preset().name(),existingNames);
+    for (auto &presetEntry : this->currentBank.presets())
+    {
+        if (presetsSet.contains(presetEntry->instanceId()))
+        {
+            std::string uniqueName = makeUniqueName(presetEntry->preset().name(), existingNames);
             existingNames.insert(uniqueName);
             Pedalboard t = presetEntry->preset();
             t.name(uniqueName);
             bankFile.addPreset(t);
         }
     }
-    SaveBankFile(indexEntry.name(),bankFile);
+    SaveBankFile(indexEntry.name(), bankFile);
     return -1;
 }
 
@@ -801,17 +818,15 @@ std::vector<PresetIndexEntry> Storage::RequestBankPresets(int64_t bankInstanceId
 
     std::vector<PresetIndexEntry> result;
     BankFile bankFile;
-    LoadBankFile(indexEntry.name(),&bankFile);
-    for (auto &preset: bankFile.presets()) {
+    LoadBankFile(indexEntry.name(), &bankFile);
+    for (auto &preset : bankFile.presets())
+    {
         result.push_back(
-            PresetIndexEntry(preset->instanceId(),preset->preset().name())
-        );
+            PresetIndexEntry(preset->instanceId(), preset->preset().name()));
     }
     return result;
 }
 
-
-
 void Storage::SetPresetIndex(const PresetIndex &presets)
 {
     // painful because we must move unique_ptrs.
@@ -885,7 +900,8 @@ Pedalboard Storage::GetPreset(int64_t instanceId) const
 int64_t Storage::DeletePresets(const std::vector<int64_t> &presetInstanceIds)
 {
     int64_t newSelection = currentBank.selectedPreset();
-    for (auto presetId: presetInstanceIds) {
+    for (auto presetId : presetInstanceIds)
+    {
         newSelection = currentBank.deletePreset(presetId);
     }
     SaveCurrentBank();
@@ -977,7 +993,7 @@ int64_t Storage::CreateNewPreset()
         }
     }
     newPedalboard.name(name);
-    auto t =  this->currentBank.addPreset(newPedalboard, -1);
+    auto t = this->currentBank.addPreset(newPedalboard, -1);
     SaveCurrentBank();
     return t;
 }
@@ -997,7 +1013,7 @@ int64_t Storage::CopyPreset(int64_t fromId, int64_t toId)
     {
         auto &toItem = this->currentBank.getItem(toId);
         toItem.preset(fromItem.preset());
-        result =  toId;
+        result = toId;
     }
     SaveCurrentBank();
     return result;
@@ -2075,21 +2091,21 @@ static bool ensureNoDotDot(const std::filesystem::path &path)
     return true;
 }
 
-static bool isInfoFile(const std::string&fileName)
+static bool isInfoFile(const std::string &fileName)
 {
-    if (strcasecmp(fileName.c_str(),"license.txt") == 0) 
+    if (strcasecmp(fileName.c_str(), "license.txt") == 0)
     {
         return true;
     }
-    if (strcasecmp(fileName.c_str(),"license.md") == 0) 
+    if (strcasecmp(fileName.c_str(), "license.md") == 0)
     {
         return true;
     }
-    if (strcasecmp(fileName.c_str(),"readme.txt") == 0) 
+    if (strcasecmp(fileName.c_str(), "readme.txt") == 0)
     {
         return true;
     }
-    if (strcasecmp(fileName.c_str(),"readme.md") == 0) 
+    if (strcasecmp(fileName.c_str(), "readme.md") == 0)
     {
         return true;
     }
@@ -3021,11 +3037,13 @@ std::string Storage::GetTone3000Auth() const
 
 std::filesystem::path Storage::FromAbstractPathString(const std::string &stringPath)
 {
-    if (stringPath.empty()) {
+    if (stringPath.empty())
+    {
         return "";
     }
-    fs::path path { stringPath};
-    if (path.is_absolute()) {
+    fs::path path{stringPath};
+    if (path.is_absolute())
+    {
         return path;
     }
     return GetPluginUploadDirectory() / path;
@@ -3048,6 +3066,125 @@ std::string Storage::FromAbstractPathJson(const std::string &pathJson)
     return v.to_string();
 }
 
+void Storage::SetChannelRouterSettings(ChannelRouterSettings::ptr settings)
+{
+    this->channelRouterSettings = settings;
+    this->channelSelection = ChannelSelection(*settings);
+    SaveChannelRouterSettings(settings);
+}
+ChannelRouterSettings::ptr Storage::GetChannelRouterSettings()
+{
+    return channelRouterSettings;
+}
+
+std::filesystem::path Storage::GetChannelRouterSettingsPath() const
+{
+    return GetDataRoot() / "ChannelRouterSettings.json";
+}
+
+void Storage::SaveChannelRouterSettings(ChannelRouterSettings::ptr settings)
+{
+    std::ofstream os(GetChannelRouterSettingsPath());
+    json_writer writer(os);
+    writer.write(settings);
+}
+ChannelRouterSettings::ptr Storage::LoadChannelRouterSettings()
+{
+    auto path = GetChannelRouterSettingsPath();
+    if (!fs::exists(path))
+    {
+        // See UpgradeChannelRouterSettings(), which will upgrade from old settings
+        // or create a default instance.
+        return nullptr; // will be upgraded later.
+    }   
+    try {
+        std::ifstream is(path);
+        json_reader reader(is);
+        ChannelRouterSettings::ptr result;
+        reader.read(&result);
+    return result;
+    } catch (const std::exception &e) {
+        Lv2Log::error("Failed to load Channel Router settings: %s", e.what());
+        return std::make_shared<ChannelRouterSettings>();
+    }
+}
+
+static int64_t GetUpgradedPortIndex(const std::string &portName)
+{
+    auto nPos = portName.find_last_of('_');
+    if (nPos != std::string::npos) 
+    {
+        std::string channelStr = portName.substr(nPos + 1);
+        try 
+        {
+            int64_t channelIndex = std::stoll(channelStr);
+            return channelIndex;
+        } catch (const std::exception &) {
+            return -1;
+        }
+    }   
+    return -1;
+}   
+void Storage::UpgradeChannelRouterSettings() 
+{
+    if (channelRouterSettings == nullptr) 
+    {
+        channelRouterSettings = std::make_shared<ChannelRouterSettings>();
+        if (jackChannelSelection.isValid()) 
+        {
+            channelRouterSettings->configured(true);
+            channelRouterSettings->mainInputChannels().resize(2);
+            const std::vector<std::string>& oldInputs = jackChannelSelection.GetInputAudioPorts();
+            std::vector<int64_t>& newInputs = channelRouterSettings->mainInputChannels();
+
+            if (oldInputs.size() ==1) 
+            {
+                int64_t leftIndex = GetUpgradedPortIndex(oldInputs[0]);
+                newInputs.resize(2);
+                newInputs[0] = leftIndex;
+                newInputs[1] = leftIndex;
+            } else if (oldInputs.size() == 2) {
+                newInputs.resize(2);
+                for (size_t i = 0; i < std::min(oldInputs.size(), newInputs.size()); ++i) 
+                {
+                    int64_t portIndex = GetUpgradedPortIndex(oldInputs[i]);
+                    newInputs[i] = portIndex;
+                }
+            }
+            const std::vector<std::string>& oldOutputs = jackChannelSelection.GetOutputAudioPorts();
+            auto &newMainOutputs = channelRouterSettings->mainOutputChannels();
+            if (oldOutputs.size() == 1) {
+                int64_t leftIndex = GetUpgradedPortIndex(oldOutputs[0]);
+                newMainOutputs.resize(2);
+                newMainOutputs[0] = leftIndex;
+                newMainOutputs[1] = leftIndex;
+            } else if (oldOutputs.size() == 2) {
+                newMainOutputs.resize(2);
+                for (size_t i = 0; i < std::min(oldOutputs.size(), newMainOutputs.size()); ++i) 
+                {
+                    int64_t portIndex = GetUpgradedPortIndex(oldOutputs[i]);
+                    newMainOutputs[i] = portIndex;
+                }
+            }
+
+            auto &newAuxInputs = channelRouterSettings->auxInputChannels();
+            newAuxInputs.resize(2);
+            newAuxInputs[0] = -1;
+            newAuxInputs[1] = -1;
+            auto &newAuxOutputs = channelRouterSettings->auxOutputChannels();
+            newAuxOutputs.resize(2);
+            newAuxOutputs[0] = -1;
+            newAuxOutputs[1] = -1;
+            SaveChannelRouterSettings(channelRouterSettings);
+        }   
+        channelSelection = ChannelSelection(*channelRouterSettings);
+    }
+}
+
+const ChannelSelection& Storage::GetChannelSelection() const {
+    return channelSelection;
+}
+
 
 JSON_MAP_BEGIN(UserSettings)
 JSON_MAP_REFERENCE(UserSettings, governor)

src/Storage.hpp

@@ -32,6 +32,8 @@
 #include <map>
 #include "FilePropertyDirectoryTree.hpp"
 #include "AlsaSequencer.hpp"
+#include "ChannelRouterSettings.hpp"
+
 
 
 namespace pipedal {
@@ -117,6 +119,15 @@ private:
     WifiDirectConfigSettings wifiDirectConfigSettings;
 
     UserSettings userSettings;
+
+    ChannelRouterSettings::ptr channelRouterSettings;
+    ChannelSelection channelSelection;
+
+    void UpgradeChannelRouterSettings();
+    std::filesystem::path GetChannelRouterSettingsPath() const;
+    void SaveChannelRouterSettings(ChannelRouterSettings::ptr settings);
+    ChannelRouterSettings::ptr LoadChannelRouterSettings();
+
 public:
     Storage();
     void Initialize();
@@ -124,8 +135,8 @@ public:
 
     void SetDataRoot(const std::filesystem::path& path);
     void SetConfigRoot(const std::filesystem::path& path);
-    const std::filesystem::path&GetConfigRoot();
-    const std::filesystem::path&GetDataRoot();
+    const std::filesystem::path&GetConfigRoot() const;
+    const std::filesystem::path&GetDataRoot() const;
 
     const std::filesystem::path &GetPluginUploadDirectory() const;
 
@@ -206,6 +217,11 @@ public:
     void SetAlsaSequencerConfiguration(const AlsaSequencerConfiguration &alsaSequencerConfiguration);
     AlsaSequencerConfiguration GetAlsaSequencerConfiguration() const;
 
+    void SetChannelRouterSettings(ChannelRouterSettings::ptr settings);
+    ChannelRouterSettings::ptr GetChannelRouterSettings();
+
+    const ChannelSelection& GetChannelSelection() const;
+
 
     //std::string MapPropertyFileName(Lv2PluginInfo*pluginInfo, const std::string&path);