use signal level meter class for meter calculation in the server (avoid doubling code), i.e., max calc and smoothing

ChangeLog

@@ -31,12 +31,10 @@
 
 
 
-TODO use signal level meter class for meter calculation in the server (avoid doubling code), i.e., max calc and smoothing
+TODO add new register message which contains version and, e.g., max number of clients
 
 TODO the new translation loading does not work on MacOS
 
-TODO add new register message which contains version and, e.g., max number of clients
-
 TODO https://github.com/corrados/jamulus/issues/341#issuecomment-647172946
      - generate .qm on compile time with lrelease
      - download nsProcess.dll on Windows installer creation instead of put it in the repo

src/channel.cpp

@@ -35,7 +35,8 @@ CChannel::CChannel ( const bool bNIsServer ) :
     iFadeInCntMax          ( FADE_IN_NUM_FRAMES_DBLE_FRAMESIZE ),
     bIsEnabled             ( false ),
     bIsServer              ( bNIsServer ),
-    iAudioFrameSizeSamples ( DOUBLE_SYSTEM_FRAME_SIZE_SAMPLES )
+    iAudioFrameSizeSamples ( DOUBLE_SYSTEM_FRAME_SIZE_SAMPLES ),
+    SignalLevelMeter       ( false, 0.5 ) // server mode with mono out and faster smoothing
 {
     // reset network transport properties
     ResetNetworkTransportProperties();
@@ -568,6 +569,9 @@ EPutDataStat CChannel::PutAudioData ( const CVector<uint8_t>& vecbyData,
 
                 // init audio fade-in counter
                 iFadeInCnt = 0;
+
+                // init level meter
+                SignalLevelMeter.Reset();
             }
 
             // reset time-out counter (note that this must be done after the
@@ -658,6 +662,18 @@ void CChannel::PrepAndSendPacket ( CHighPrioSocket*        pSocket,
     }
 }
 
+double CChannel::UpdateAndGetLevelForMeterdB ( const CVector<short>& vecsAudio,
+                                               const int             iInSize,
+                                               const bool            bIsStereoIn )
+{
+    // update the signal level meter and immediately return the current value
+    SignalLevelMeter.Update ( vecsAudio,
+                              iInSize,
+                              bIsStereoIn );
+
+    return SignalLevelMeter.GetLevelForMeterdBLeftOrMono();
+}
+
 int CChannel::GetUploadRateKbps()
 {
     const int iAudioSizeOut = iNetwFrameSizeFact * iAudioFrameSizeSamples;

src/channel.h

@@ -175,8 +175,9 @@ public:
 
     bool ChannelLevelsRequired() const { return bChannelLevelsRequired; }
 
-    double GetPrevLevel() const              { return dPrevLevel; }
+    double UpdateAndGetLevelForMeterdB ( const CVector<short>& vecsAudio,
-    void   SetPrevLevel ( const double nPL ) { dPrevLevel = nPL; }
+                                         const int             iInSize,
+                                         const bool            bIsStereoIn );
 
 protected:
     bool ProtocolIsEnabled();
@@ -190,8 +191,6 @@ protected:
         iNetwFrameSizeFact    = FRAME_SIZE_FACTOR_PREFERRED;
         iNetwFrameSize        = CELT_MINIMUM_NUM_BYTES;
         iNumAudioChannels     = 1; // mono
-
-        dPrevLevel            = 0.0;
     }
 
     // connection parameters
@@ -235,7 +234,8 @@ protected:
     QMutex                  MutexConvBuf;
 
     bool                    bChannelLevelsRequired;
-    double            dPrevLevel;
+
+    CStereoSignalLevelMeter SignalLevelMeter;
 
 public slots:
     void OnSendProtMessage ( CVector<uint8_t> vecMessage );

src/client.cpp

@@ -989,7 +989,9 @@ void CClient::ProcessAudioDataIntern ( CVector<int16_t>& vecsStereoSndCrd )
 
     // Transmit signal ---------------------------------------------------------
     // update stereo signal level meter
-    SignalLevelMeter.Update ( vecsStereoSndCrd );
+    SignalLevelMeter.Update ( vecsStereoSndCrd,
+                              iMonoBlockSizeSam,
+                              true );
 
     // add reverberation effect if activated
     if ( iReverbLevel != 0 )

src/client.h

@@ -117,7 +117,7 @@ public:
     bool   IsRunning() { return Sound.IsRunning(); }
     bool   SetServerAddr ( QString strNAddr );
 
-    double GetLevelForMeterdBLeft()  { return SignalLevelMeter.GetLevelForMeterdBLeft(); }
+    double GetLevelForMeterdBLeft()  { return SignalLevelMeter.GetLevelForMeterdBLeftOrMono(); }
     double GetLevelForMeterdBRight() { return SignalLevelMeter.GetLevelForMeterdBRight(); }
 
     bool   GetAndResetbJitterBufferOKFlag();

src/server.cpp

@@ -1663,7 +1663,6 @@ bool CServer::CreateLevelsForAllConChannels ( const int                        i
                                               const CVector<CVector<int16_t> > vecvecsData,
                                               CVector<uint16_t>&               vecLevelsOut )
 {
-    int  i, j, k;
     bool bLevelsWereUpdated = false;
 
     // low frequency updates
@@ -1675,44 +1674,15 @@ bool CServer::CreateLevelsForAllConChannels ( const int                        i
         // init return vector with zeros since we mix all channels on that vector
         vecLevelsOut.Reset ( 0 );
 
-        for ( j = 0; j < iNumClients; j++ )
+        for ( int j = 0; j < iNumClients; j++ )
         {
-            // get a reference to the audio data
+            // update and get signal level for meter in dB for each channel
-            const CVector<int16_t>& vecsData = vecvecsData[j];
+            const double dCurSigLevelForMeterdB = vecChannels[vecChanIDsCurConChan[j]].
-
+                UpdateAndGetLevelForMeterdB ( vecvecsData[j],
-            // Speed optimization:
+                                              iServerFrameSizeSamples,
-            // - we only make use of the negative values and ignore the positive ones (since
+                                              vecNumAudioChannels[j] > 1 );
-            //   int16 has range {-32768, 32767}) -> we do not need to call the fabs() function
-            // - we only evaluate every third sample
-            int16_t sMax = 0;
-
-            if ( vecNumAudioChannels[j] == 1 )
-            {
-                // mono
-                for ( i = 0; i < iServerFrameSizeSamples; i += 3 )
-                {
-                    sMax = std::min ( sMax, vecsData[i] );
-                }
-            }
-            else
-            {
-                // stereo
-                for ( i = 0, k = 0; i < iServerFrameSizeSamples; i += 3, k += 6 ) // 2 * 3 = 6 -> stereo
-                {
-                    // left/right channels separately
-                    sMax = std::min ( sMax, vecsData[k] );
-                    sMax = std::min ( sMax, vecsData[k + 1] );
-                }
-            }
-
-            // smoothing
-            const int    iChId     = vecChanIDsCurConChan[j];
-            const double dCurLevel = std::max ( -static_cast<double> ( sMax ), vecChannels[iChId].GetPrevLevel() * 0.5 );
-            vecChannels[iChId].SetPrevLevel ( dCurLevel );
-
-            // logarithmic measure
-            double dCurSigLevelForMeterdB = CStereoSignalLevelMeter::CalcLogResultForMeter ( dCurLevel );
 
+            // map value to integer for transmission via the protocol (4 bit available)
             vecLevelsOut[j] = static_cast<uint16_t> ( ceil ( dCurSigLevelForMeterdB ) );
         }
     }

src/util.cpp

@@ -28,11 +28,10 @@
 
 /* Implementation *************************************************************/
 // Input level meter implementation --------------------------------------------
-void CStereoSignalLevelMeter::Update ( const CVector<short>& vecsAudio )
+void CStereoSignalLevelMeter::Update ( const CVector<short>& vecsAudio,
+                                       const int             iMonoBlockSizeSam,
+                                       const bool            bIsStereoIn )
 {
-    // get the stereo vector size
-    const int iStereoVecSize = vecsAudio.Size();
-
     // Get maximum of current block
     //
     // Speed optimization:
@@ -43,32 +42,50 @@ void CStereoSignalLevelMeter::Update ( const CVector<short>& vecsAudio )
     // With these speed optimizations we might loose some information in
     // special cases but for the average music signals the following code
     // should give good results.
-    short sMaxL = 0;
+    short sMinLOrMono = 0;
-    short sMaxR = 0;
+    short sMinR       = 0;
 
-    for ( int i = 0; i < iStereoVecSize; i += 6 ) // 2 * 3 = 6 -> stereo
+    if ( bIsStereoIn )
     {
-        // left channel
+        // stereo in
-        sMaxL = std::min ( sMaxL, vecsAudio[i] );
+        for ( int i = 0; i < 2 * iMonoBlockSizeSam; i += 6 ) // 2 * 3 = 6 -> stereo
-
+        {
-        // right channel
+            // left (or mono) and right channel
-        sMaxR = std::min ( sMaxR, vecsAudio[i + 1] );
+            sMinLOrMono = std::min ( sMinLOrMono, vecsAudio[i] );
+            sMinR       = std::min ( sMinR,       vecsAudio[i + 1] );
         }
 
-    dCurLevelL = UpdateCurLevel ( dCurLevelL, -sMaxL );
+        // in case of mono out use minimum of both channels
-    dCurLevelR = UpdateCurLevel ( dCurLevelR, -sMaxR );
+        if ( !bIsStereoOut )
+        {
+            sMinLOrMono = std::min ( sMinLOrMono, sMinR );
+        }
+    }
+    else
+    {
+        // mono in
+        for ( int i = 0; i < iMonoBlockSizeSam; i += 3 )
+        {
+            sMinLOrMono = std::min ( sMinLOrMono, vecsAudio[i] );
+        }
+    }
+
+    // apply smoothing, if in stereo out mode, do this for two channels
+    dCurLevelLOrMono = UpdateCurLevel ( dCurLevelLOrMono, -sMinLOrMono );
+
+    if ( bIsStereoOut )
+    {
+        dCurLevelR = UpdateCurLevel ( dCurLevelR, -sMinR );
+    }
 }
 
 double CStereoSignalLevelMeter::UpdateCurLevel ( double       dCurLevel,
-                                                 double dMax )
+                                                 const double dMax )
 {
     // decrease max with time
     if ( dCurLevel >= METER_FLY_BACK )
     {
-// TODO Calculate factor from sample rate and frame size (64 or 128 samples frame size).
+        dCurLevel *= dSmoothingFactor;
-//      But tests with 128 and 64 samples frame size have shown that the meter fly back
-//      is ok for both numbers of samples frame size.
-        dCurLevel *= 0.97;
     }
     else
     {

src/util.h

@@ -712,25 +712,35 @@ enum ESkillLevel
 class CStereoSignalLevelMeter
 {
 public:
-    CStereoSignalLevelMeter() { Reset(); }
+// TODO Calculate smoothing factor from sample rate and frame size (64 or 128 samples frame size).
+//      But tests with 128 and 64 samples frame size have shown that the meter fly back
+//      is ok for both numbers of samples frame size with a factor of 0.97.
+    CStereoSignalLevelMeter ( const bool   bNIsStereoOut     = true,
+                              const double dNSmoothingFactor = 0.97 ) :
+        dSmoothingFactor ( dNSmoothingFactor ), bIsStereoOut ( bNIsStereoOut ) { Reset(); }
 
-    void          Update ( const CVector<short>& vecsAudio );
+    void Update ( const CVector<short>& vecsAudio,
-    double        GetLevelForMeterdBLeft()  { return CalcLogResultForMeter ( dCurLevelL ); }
+                  const int             iInSize,
+                  const bool            bIsStereoIn );
+
+    double        GetLevelForMeterdBLeftOrMono() { return CalcLogResultForMeter ( dCurLevelLOrMono ); }
     double        GetLevelForMeterdBRight()      { return CalcLogResultForMeter ( dCurLevelR ); }
     static double CalcLogResultForMeter ( const double& dLinearLevel );
 
     void Reset()
     {
-        dCurLevelL = 0.0;
+        dCurLevelLOrMono = 0.0;
         dCurLevelR       = 0.0;
     }
 
 protected:
     double UpdateCurLevel ( double       dCurLevel,
-                            double dMax );
+                            const double dMax );
 
-    double dCurLevelL;
+    double dCurLevelLOrMono;
     double dCurLevelR;
+    double dSmoothingFactor;
+    bool   bIsStereoOut;
 };