- statistics improved + allow to use virtual microphone AND/OR speaker + minor cleanups

Lets a host inject e.g. NullInputDevice before start() so the default
platform microphone is not constructed, avoiding the RECORD_AUDIO
permission on Android while leaving the real speaker output in place.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/engine/agent/Agent_AudioManager.cpp

@@ -26,16 +26,6 @@ AudioManager::~AudioManager()
     // stop();
 }
 
-AudioManager& AudioManager::instance()
-{
-    static std::shared_ptr<AudioManager> GAudioManager;
-
-    if (!GAudioManager)
-        GAudioManager = std::make_shared<AudioManager>();
-
-    return *GAudioManager;
-}
-
 void AudioManager::setTerminal(MT::Terminal* terminal)
 {
     mTerminal = terminal;
@@ -67,6 +57,7 @@ void AudioManager::start(int usageId)
     if (mUsage.obtain(usageId) > 1)
         return;
 
+    // Maybe it is time to initialize global audio support
     if (Audio::OsEngine::instance())
         Audio::OsEngine::instance()->open();
 
@@ -89,14 +80,15 @@ void AudioManager::start(int usageId)
             enumerator->open(Audio::myMicrophone);
             int inputIndex = enumerator->indexOfDefaultDevice();
 
-            // Construct and set to terminal's audio pair input device
+            // Construct default platform input device
             if (usageId != atNull)
                 mAudioInput = Audio::PInputDevice(Audio::InputDevice::make(enumerator->idAt(inputIndex)));
             else
                 mAudioInput = Audio::PInputDevice(new Audio::NullInputDevice());
-
-            mTerminal->audio()->setInput(mAudioInput);
         }
+        // Bind input to the terminal's device pair regardless of whether it was
+        // just constructed or externally injected via setAudioInput().
+        mTerminal->audio()->setInput(mAudioInput);
 
         if (!mAudioOutput)
         {
@@ -104,7 +96,7 @@ void AudioManager::start(int usageId)
             enumerator->open(Audio::mySpeaker);
             int outputIndex = enumerator->indexOfDefaultDevice();
 
-            // Construct and set terminal's audio pair output device
+            // Construct default platform output device
             if (usageId != atNull)
             {
                 if (outputIndex >= enumerator->count())
@@ -115,9 +107,8 @@ void AudioManager::start(int usageId)
             }
             else
                 mAudioOutput = Audio::POutputDevice(new Audio::NullOutputDevice());
-
-            mTerminal->audio()->setOutput(mAudioOutput);
         }
+        mTerminal->audio()->setOutput(mAudioOutput);
     }
 
     // Open audio
@@ -167,6 +158,18 @@ void AudioManager::stop(int usageId)
     }
 }
 
+void AudioManager::setAudioInput(Audio::PInputDevice input)
+{
+    LOCK_MANAGER;
+    mAudioInput = std::move(input);
+}
+
+void AudioManager::setAudioOutput(Audio::POutputDevice output)
+{
+    LOCK_MANAGER;
+    mAudioOutput = std::move(output);
+}
+
 void AudioManager::startPlayFile(int usageId, const std::string& path, AudioTarget target, LoopMode lm, int timelimit)
 {
     // Check if file exists
@@ -202,6 +205,6 @@ void AudioManager::process()
     mPlayer.releasePlayed();
     std::vector<int> ids;
     mTerminal->audio()->player().retrieveUsageIds(ids);
-    for (unsigned i=0; i<ids.size(); i++)
+    for (int id : ids)
-        stop(ids[i]);
+        stop(id);
 }

src/engine/agent/Agent_AudioManager.h

@@ -37,7 +37,7 @@ public:
     AudioManager();
     virtual ~AudioManager();
 
-    static AudioManager& instance();
+    // static AudioManager& instance();
 
     // Enforces to close audio devices. Used to shutdown AudioManager on exit from application
     void close();
@@ -53,6 +53,12 @@ public:
     void start(int usageId);
     void stop(int usageId);
 
+    // Inject a custom input device. Must be called before start(): when set,
+    // start() skips construction of the default platform microphone. Pass an
+    // empty pointer to clear the override.
+    void setAudioInput(Audio::PInputDevice input);
+    void setAudioOutput(Audio::POutputDevice output);
+
     enum AudioTarget
     {
         atNull,

src/engine/agent/Agent_Impl.cpp

@@ -3,10 +3,11 @@
 #include "helper/HL_String.h"
 #include "helper/HL_StreamState.h"
 #include "helper/HL_VariantMap.h"
-#include "helper/HL_CsvReader.h"
+// #include "helper/HL_CsvReader.h"
-#include "helper/HL_Base64.h"
+// #include "helper/HL_Base64.h"
 #include "media/MT_CodecList.h"
-#include <fstream>
+#include "audio/Audio_Null.h"
+// #include <fstream>
 
 
 const std::string Status_Ok = "ok";
@@ -226,12 +227,6 @@ void AgentImpl::processStart(JsonCpp::Value& request, JsonCpp::Value &answer)
     for (int i=0; i<cl.count(); i++)
         priorityConfig->at(i) = i;
 
-    // Disable dynamic payload codec types - commented for now
-    // if (cl.codecAt(i).payloadType() < 96)
-    //    priorityConfig->at(i) = i;
-    // else
-    //    priorityConfig->at(i) = -1;
-
     config()[CONFIG_CODEC_PRIORITY] = priorityConfig;
 
     // Enable audio
@@ -341,6 +336,11 @@ void AgentImpl::processStartSession(JsonCpp::Value& request, JsonCpp::Value& ans
         return;
     }
 
+    if (request["use_null_mic"].asBool())
+        mAudioManager->setAudioInput(std::make_shared<Audio::NullInputDevice>());
+    if (request["use_null_spk"].asBool())
+        mAudioManager->setAudioOutput(std::make_shared<Audio::NullOutputDevice>());
+
     mAudioManager->start(mUseNativeAudio ? AudioManager::atReceiver : AudioManager::atNull);
 
     auto sessionIter = mSessionMap.find(request["session_id"].asInt());
@@ -440,6 +440,10 @@ void AgentImpl::processAcceptSession(JsonCpp::Value& request, JsonCpp::Value& an
         else
         {
             // Ensure audio manager is here
+            if (request["use_null_mic"].asBool())
+                mAudioManager->setAudioInput(std::make_shared<Audio::NullInputDevice>());
+            if (request["use_null_spk"].asBool())
+                mAudioManager->setAudioOutput(std::make_shared<Audio::NullOutputDevice>());
             mAudioManager->start(mUseNativeAudio ? AudioManager::atReceiver : AudioManager::atNull);
 
             // Accept session on SIP level

src/engine/audio/Audio_Null.cpp

@@ -5,8 +5,9 @@
 #define LOG_SUBSYSTEM "audio"
 
 using namespace Audio;
+using namespace std::chrono_literals;
 
-NullTimer::NullTimer(int interval, Delegate *delegate, const char* name)
+NullTimer::NullTimer(std::chrono::milliseconds interval, Delegate *delegate, const char* name)
     :mShutdown(false), mDelegate(delegate), mInterval(interval), mThreadName(name)
 {
     start();
@@ -32,23 +33,23 @@ void NullTimer::stop()
 
 void NullTimer::run()
 {
-  mTail = 0;
+    mTail = 0us;
     while (!mShutdown)
     {
         // Get current timestamp
         std::chrono::system_clock::time_point timestamp = std::chrono::system_clock::now();
 
-    while (mTail >= mInterval * 1000)
+        while (mTail >= mInterval)
         {
             if (mDelegate)
                 mDelegate->onTimerSignal(*this);
-      mTail -= mInterval * 1000;
+            mTail -= mInterval;
         }
 
         // Sleep for mInterval - mTail milliseconds
-    std::this_thread::sleep_for(std::chrono::microseconds(mInterval * 1000 - mTail));
+        std::this_thread::sleep_for(mInterval - mTail);
 
-    mTail += (int)std::chrono::duration_cast<std::chrono::microseconds>(std::chrono::system_clock::now() - timestamp).count();
+        mTail = mTail + std::chrono::duration_cast<std::chrono::microseconds>(std::chrono::system_clock::now() - timestamp);
     }
 }
 
@@ -65,16 +66,19 @@ NullInputDevice::~NullInputDevice()
 
 bool NullInputDevice::open()
 {
+    ICELogInfo(<< "Starting NullInputDevice for " << AUDIO_MIC_BUFFER_LENGTH << "ms buffers");
     mBuffer = malloc(AUDIO_MIC_BUFFER_SIZE);
     memset(mBuffer, 0, AUDIO_MIC_BUFFER_SIZE);
     mTimeCounter = 0; mDataCounter = 0;
+
     // Creation of timer starts it also. So first onTimerSignal can come even before open() returns.
-  mTimer = std::make_shared<NullTimer>(AUDIO_MIC_BUFFER_LENGTH, this, "NullMicrophoneThread");
+    mTimer = std::make_shared<NullTimer>(std::chrono::milliseconds(AUDIO_MIC_BUFFER_LENGTH), this, "null_mic");
     return true;
 }
 
 void NullInputDevice::internalClose()
 {
+    ICELogInfo(<< "Stopping NullInputDevice");
     mTimer.reset();
     if (mBuffer)
     {
@@ -88,10 +92,12 @@ void NullInputDevice::close()
 {
     internalClose();
 }
+
 Format NullInputDevice::getFormat()
 {
     assert (Format().sizeFromTime(AUDIO_MIC_BUFFER_LENGTH) == AUDIO_MIC_BUFFER_SIZE);
-  return Format();
+
+    return {}; // Return library-define default format
 }
 
 void NullInputDevice::onTimerSignal(NullTimer& timer)
@@ -119,7 +125,7 @@ bool NullOutputDevice::open()
     mTimeCounter = 0; mDataCounter = 0;
     mBuffer = malloc(AUDIO_SPK_BUFFER_SIZE);
     // Creation of timer starts it also. So first onSpkData() can come before open() returns even.
-  mTimer = std::make_shared<NullTimer>(AUDIO_SPK_BUFFER_LENGTH, this, "NullSpeakerThread");
+    mTimer = std::make_shared<NullTimer>(std::chrono::milliseconds(AUDIO_SPK_BUFFER_LENGTH), this, "null_spk");
     return true;
 }
 

src/engine/audio/Audio_Null.h

@@ -2,6 +2,7 @@
 #define __AUDIO_NULL_H
 
 #include <thread>
+#include <chrono>
 #include "Audio_Interface.h"
 
 namespace Audio
@@ -17,10 +18,10 @@ namespace Audio
 
 protected:
     std::thread mWorkerThread;
-    volatile bool mShutdown;
+    std::atomic_bool mShutdown = {false};
-    Delegate* mDelegate;
+    Delegate* mDelegate = nullptr;
-    int mInterval,  // Interval - wanted number of milliseconds
+    std::chrono::milliseconds mInterval;    // Interval - wanted number of milliseconds
-        mTail; // Number of milliseconds that can be sent immediately to sink
+    std::chrono::microseconds mTail;        // Number of milliseconds that can be sent immediately to sink
     std::string mThreadName;
 
     void start();
@@ -28,7 +29,7 @@ namespace Audio
     void run();
 public:
     /* Interval is in milliseconds. */
-    NullTimer(int interval, Delegate* delegate, const char* name = nullptr);
+    NullTimer(std::chrono::milliseconds interval, Delegate* delegate, const char* name = nullptr);
     ~NullTimer();
 };
 
@@ -83,8 +84,8 @@ namespace Audio
     std::tstring nameAt(int index) override;
     int idAt(int index) override;
     int indexOfDefaultDevice() override;
-
 };
+
 }
 
 #endif

src/engine/endpoint/EP_Engine.h

@@ -108,7 +108,7 @@ enum
     CONFIG_ACCOUNT,             // VariantMap with account configuration
     CONFIG_EXTERNALIP,          // Use external/public IP in outgoing requests
     CONFIG_OWN_DNS,             // Use predefined DNS servers
-    CONFIG_REGID                // reg-id value from RFC5626
+    CONFIG_REGID                // reg-id value from RFC5626,
 };
 
 // Conntype parameter for OnSessionEstablished event

src/engine/endpoint/EP_Session.cpp

@@ -453,7 +453,7 @@ void Session::getSessionInfo(Session::InfoOptions options, VariantMap& info)
 
         media = &stream;
         MT::Statistics s = stream.provider()->getStatistics();
-        info[SessionInfo_NetworkMos] = static_cast<float>(s.calculateMos(4.14));
+        info[SessionInfo_NetworkMos] = static_cast<float>(s.calculateMos());
         info[SessionInfo_AudioCodec] = s.mCodecName;
 
         stat += s;

src/engine/media/MT_AudioStream.cpp

@@ -344,14 +344,20 @@ void AudioStream::dataArrived(PDatagramSocket s, const void* buffer, int length,
     }
 
     mStat.mReceived += length;
+    auto& perDst = mStat.mPerDestination[source];
+    perDst.mReceivedBytes += length;
     if (RtpHelper::isRtp(mReceiveBuffer, receiveLength))
     {
         if (!mStat.mFirstRtpTime)
             mStat.mFirstRtpTime = std::chrono::steady_clock::now();
         mStat.mReceivedRtp++;
+        perDst.mReceivedRtp++;
     }
     else
+    {
         mStat.mReceivedRtcp++;
+        perDst.mReceivedRtcp++;
+    }
 
     mRtpSession.Poll(); // maybe it is extra with external transmitter
     bool hasData = mRtpSession.GotoFirstSourceWithData();

src/engine/media/MT_NativeRtpSender.cpp

@@ -47,6 +47,9 @@ bool NativeRtpSender::SendRTP(const void *data, size_t len)
     mSocket.mRtp->sendDatagram(mTarget.mRtp, mSendBuffer, sendLength);
     mStat.mSentRtp++;
     mStat.mSent += len;
+    auto& perDst = mStat.mPerDestination[mTarget.mRtp];
+    perDst.mSentRtp++;
+    perDst.mSentBytes += len;
 
     return true;
 }
@@ -73,6 +76,9 @@ bool NativeRtpSender::SendRTCP(const void *data, size_t len)
     mSocket.mRtcp->sendDatagram(mTarget.mRtcp, mSendBuffer, sendLength);
     mStat.mSentRtcp++;
     mStat.mSent += len;
+    auto& perDst = mStat.mPerDestination[mTarget.mRtcp];
+    perDst.mSentRtcp++;
+    perDst.mSentBytes += len;
 
     return true;
 }

src/engine/media/MT_Statistics.cpp

@@ -2,6 +2,7 @@
 #include <cctype>
 #include <cstring>
 #include <iostream>
+#include <sstream>
 
 #include "MT_Statistics.h"
 #define LOG_SUBSYSTEM "media"
@@ -203,7 +204,7 @@ void Statistics::calculateBurstr(double* burstr, double* lossr) const
         *lossr = 0;
 }
 
-double Statistics::calculateMos(double maximalMos) const
+double Statistics::calculateMos() const
 {
     // Network MOS via the simplified ITU-T G.107 E-Model:
     //
@@ -211,7 +212,7 @@ double Statistics::calculateMos(double maximalMos) const
     //   Id       = 0.024*d + 0.11*max(0, d - 177.3)
     //   Ie_eff   = Ie + (95 - Ie) * Ppl / (Ppl + Bpl)         (BurstR=1)
     //   R        = 93.2 - Id - Ie_eff                          (clamped to [0,100])
-    //   MOS      = 1 + 0.035*R + 7e-6*R*(R-60)*(100-R)        (clamped to [1, maximalMos])
+    //   MOS      = 1 + 0.035*R + 7e-6*R*(R-60)*(100-R)        (clamped >= 1)
     //
     // Ie/Bpl are looked up from a per-codec table; safe defaults are used
     // when the codec is unknown.
@@ -254,7 +255,6 @@ double Statistics::calculateMos(double maximalMos) const
         mos = 1.0 + 0.035 * R + 7e-6 * R * (R - 60.0) * (100.0 - R);
 
     if (mos < 1.0) mos = 1.0;
-    if (mos > maximalMos) mos = maximalMos;
     return mos;
 }
 
@@ -306,6 +306,17 @@ Statistics& Statistics::operator += (const Statistics& src)
     mRemotePeer             = src.mRemotePeer;
     mSsrc                   = src.mSsrc;
 
+    for (const auto& [addr, counts]: src.mPerDestination)
+    {
+        auto& dst = mPerDestination[addr];
+        dst.mSentRtp       += counts.mSentRtp;
+        dst.mSentRtcp      += counts.mSentRtcp;
+        dst.mSentBytes     += counts.mSentBytes;
+        dst.mReceivedRtp   += counts.mReceivedRtp;
+        dst.mReceivedRtcp  += counts.mReceivedRtcp;
+        dst.mReceivedBytes += counts.mReceivedBytes;
+    }
+
     return *this;
 }
 
@@ -330,6 +341,19 @@ Statistics& Statistics::operator -= (const Statistics& src)
             mCodecCount[codecStat.first] -= codecStat.second;
     }
 
+    for (const auto& [addr, counts]: src.mPerDestination)
+    {
+        auto it = mPerDestination.find(addr);
+        if (it == mPerDestination.end())
+            continue;
+        it->second.mSentRtp       -= counts.mSentRtp;
+        it->second.mSentRtcp      -= counts.mSentRtcp;
+        it->second.mSentBytes     -= counts.mSentBytes;
+        it->second.mReceivedRtp   -= counts.mReceivedRtp;
+        it->second.mReceivedRtcp  -= counts.mReceivedRtcp;
+        it->second.mReceivedBytes -= counts.mReceivedBytes;
+    }
+
     return *this;
 }
 
@@ -345,5 +369,16 @@ std::string Statistics::toString() const
         << ", decode requested: "   << mDecodeRequested.average()
         << ", packet interval: "    << mPacketInterval.average();
 
+    for (const auto& [addr, counts]: mPerDestination)
+    {
+        oss << "; peer " << addr.toBriefStdString()
+            << " sent rtp="  << counts.mSentRtp
+            << "/rtcp="      << counts.mSentRtcp
+            << "/bytes="     << counts.mSentBytes
+            << ", received rtp=" << counts.mReceivedRtp
+            << "/rtcp="          << counts.mReceivedRtcp
+            << "/bytes="         << counts.mReceivedBytes;
+    }
+
     return oss.str();
 }

src/engine/media/MT_Statistics.h

@@ -7,7 +7,7 @@
 
 #include "helper/HL_Statistics.h"
 #include "helper/HL_Types.h"
-#include "helper/HL_InternetAddress.h"
+#include "ice/ICEAddress.h"
 
 #include "jrtplib/src/rtptimeutilities.h"
 #include "jrtplib/src/rtppacket.h"
@@ -73,6 +73,19 @@ struct Dtmf2833Event
     std::chrono::microseconds mTimestamp;
 };
 
+// Per-remote-address packet/byte counters. Split out so an aggregate
+// Statistics can break its totals down by destination/source — useful
+// for diagnosing ICE candidate switches or symmetric-RTP issues.
+struct DestinationStats
+{
+    size_t mSentRtp     = 0;
+    size_t mSentRtcp    = 0;
+    size_t mSentBytes   = 0;
+    size_t mReceivedRtp   = 0;
+    size_t mReceivedRtcp  = 0;
+    size_t mReceivedBytes = 0;
+};
+
 class Statistics
 {
 public:
@@ -88,6 +101,10 @@ public:
                                     mPacketDropped = 0,   // Number of dropped packets (due to time unsync when playing)б
                                     mIllegalRtp = 0;      // Number of rtp packets with bad payload type
 
+    // Per-remote-address breakdown of the totals above. Keyed by the remote
+    // RTP/RTCP socket address (NAT-mapped, after ICE selection).
+    std::map<ice::NetworkAddress, DestinationStats> mPerDestination;
+
     TestResult<float>               mDecodingInterval,      // Average interval on call to packet decode
                                     mDecodeRequested,       // Average amount of requested audio frames to play
                                     mPacketInterval;        // Average interval between packet adding to jitter buffer
@@ -115,7 +132,7 @@ public:
 
     // It is to calculate network MOS
     void calculateBurstr(double* burstr, double* loss) const;
-    double calculateMos(double maximalMos) const;
+    double calculateMos() const;
 
     Statistics();
     ~Statistics();