Merge pull request #42 from pljones/feature/channel-meters

Feature/channel meters

src/audiomixerboard.cpp

@@ -34,17 +34,29 @@ CChannelFader::CChannelFader ( QWidget*     pNW,
     // create new GUI control objects and store pointers to them (note that
     // QWidget takes the ownership of the pMainGrid so that this only has
     // to be created locally in this constructor)
-    pFrame                      = new QFrame      ( pNW );
+    pFrame                      = new QFrame            ( pNW );
-    QVBoxLayout* pMainGrid      = new QVBoxLayout ( pFrame );
+
-    pFader                      = new QSlider     ( Qt::Vertical, pFrame );
+    pLevelsBox                  = new QWidget           ( pFrame );
-    pcbMute                     = new QCheckBox   ( "Mute",       pFrame );
+    plbrChannelLevel            = new CMultiColorLEDBar ( pLevelsBox );
-    pcbSolo                     = new QCheckBox   ( "Solo",       pFrame );
+    pFader                      = new QSlider           ( Qt::Vertical, pLevelsBox );
-    pLabelInstBox               = new QGroupBox   ( pFrame );
+
-    plblLabel                   = new QLabel      ( "",           pFrame );
+    pMuteSoloBox                = new QWidget           ( pFrame );
-    plblInstrument              = new QLabel      ( pFrame );
+    pcbMute                     = new QCheckBox         ( "Mute",       pMuteSoloBox );
-    plblCountryFlag             = new QLabel      ( pFrame );
+    pcbSolo                     = new QCheckBox         ( "Solo",       pMuteSoloBox );
-    QHBoxLayout* pLabelGrid     = new QHBoxLayout ( pLabelInstBox );
+
-    QVBoxLayout* pLabelPictGrid = new QVBoxLayout();
+    pLabelInstBox               = new QGroupBox         ( pFrame );
+    plblLabel                   = new QLabel            ( "",           pFrame );
+    plblInstrument              = new QLabel            ( pFrame );
+    plblCountryFlag             = new QLabel            ( pFrame );
+
+    QVBoxLayout* pMainGrid      = new QVBoxLayout       ( pFrame );
+    QHBoxLayout* pLevelsGrid    = new QHBoxLayout       ( pLevelsBox );
+    QVBoxLayout* pMuteSoloGrid  = new QVBoxLayout       ( pMuteSoloBox );
+    QHBoxLayout* pLabelGrid     = new QHBoxLayout       ( pLabelInstBox );
+    QVBoxLayout* pLabelPictGrid = new QVBoxLayout       ( );
+
+    // setup channel level
+    plbrChannelLevel->setContentsMargins( 0, 3, 2, 3 );
 
     // setup slider
     pFader->setPageStep ( 1 );
@@ -62,18 +74,30 @@ CChannelFader::CChannelFader ( QWidget*     pNW,
 
     // set margins of the layouts to zero to get maximum space for the controls
     pMainGrid->setContentsMargins ( 0, 0, 0, 0 );
+
+    pLevelsGrid->setContentsMargins ( 0, 0, 0, 0 );
+    pLevelsGrid->setSpacing ( 0 ); // only minimal space
+
+    pMuteSoloGrid->setContentsMargins ( 0, 0, 0, 0 );
+
     pLabelGrid->setContentsMargins ( 0, 0, 0, 0 );
     pLabelGrid->setSpacing ( 2 ); // only minimal space between picture and text
 
     // add user controls to the grids
     pLabelPictGrid->addWidget ( plblCountryFlag, 0, Qt::AlignHCenter );
     pLabelPictGrid->addWidget ( plblInstrument,  0, Qt::AlignHCenter );
+
     pLabelGrid->addLayout ( pLabelPictGrid );
     pLabelGrid->addWidget ( plblLabel, 0, Qt::AlignVCenter );
 
-    pMainGrid->addWidget ( pFader,  0, Qt::AlignHCenter );
+    pLevelsGrid->addWidget ( plbrChannelLevel, 0, Qt::AlignRight );
-    pMainGrid->addWidget ( pcbMute, 0, Qt::AlignLeft );
+    pLevelsGrid->addWidget ( pFader,           0, Qt::AlignLeft );
-    pMainGrid->addWidget ( pcbSolo, 0, Qt::AlignLeft );
+
+    pMuteSoloGrid->addWidget ( pcbMute,    0, Qt::AlignLeft );
+    pMuteSoloGrid->addWidget ( pcbSolo,    0, Qt::AlignLeft );
+
+    pMainGrid->addWidget ( pLevelsBox,   0, Qt::AlignHCenter );
+    pMainGrid->addWidget ( pMuteSoloBox, 0, Qt::AlignHCenter );
     pMainGrid->addWidget ( pLabelInstBox );
 
     // add fader frame to audio mixer board layout
@@ -83,17 +107,23 @@ CChannelFader::CChannelFader ( QWidget*     pNW,
     Reset();
 
     // add help text to controls
+    plbrChannelLevel->setWhatsThis ( tr ( "<b>Channel Level:</b> Displays the "
+        "pre-fader audio level of this channel.  All connected clients at the "
+        "server will be assigned an audio level, the same value for each client." ) );
+    plbrChannelLevel->setAccessibleName ( tr ( "Input level of the current audio "
+        "channel at the server" ) );
+
     pFader->setWhatsThis ( tr ( "<b>Mixer Fader:</b> Adjusts the audio level of "
         "this channel. All connected clients at the server will be assigned "
-        "an audio fader at each client." ) );
+        "an audio fader at each client, adjusting the local mix." ) );
-    pFader->setAccessibleName ( tr ( "Mixer level setting of the connected client "
+    pFader->setAccessibleName ( tr ( "Local mix level setting of the current audio "
-        "at the server" ) );
+        "channel at the server" ) );
 
-    pcbMute->setWhatsThis ( tr ( "<b>Mute:</b> With the Mute checkbox, the current "
+    pcbMute->setWhatsThis ( tr ( "<b>Mute:</b> With the Mute checkbox, the "
         "audio channel can be muted." ) );
     pcbMute->setAccessibleName ( tr ( "Mute button" ) );
 
-    pcbSolo->setWhatsThis ( tr ( "<b>Solo:</b> With the Solo checkbox, the current "
+    pcbSolo->setWhatsThis ( tr ( "<b>Solo:</b> With the Solo checkbox, the "
         "audio channel can be set to solo which means that all other channels "
         "except of the current channel are muted. It is possible to set more than "
         "one channel to solo." ) );
@@ -158,6 +188,11 @@ void CChannelFader::SetGUIDesign ( const EGUIDesign eNewDesign )
     }
 }
 
+void CChannelFader::SetDisplayChannelLevel ( const bool eNDCL )
+{
+    plbrChannelLevel->setHidden( !eNDCL );
+}
+
 void CChannelFader::SetupFaderTag ( const ESkillLevel eSkillLevel )
 {
     // setup group box for label/instrument picture: set a thick black border
@@ -306,6 +341,11 @@ void CChannelFader::UpdateSoloState ( const bool bNewOtherSoloState )
     }
 }
 
+void CChannelFader::SetChannelLevel ( const uint16_t iLevel )
+{
+    plbrChannelLevel->setValue ( iLevel );
+}
+
 void CChannelFader::SetText ( const CChannelInfo& ChanInfo )
 {
     // store original received name
@@ -634,6 +674,17 @@ void CAudioMixerBoard::SetGUIDesign ( const EGUIDesign eNewDesign )
     }
 }
 
+void CAudioMixerBoard::SetDisplayChannelLevels ( const bool eNDCL )
+{
+    bDisplayChannelLevels = eNDCL;
+
+    // apply preference to child GUI controls
+    for ( int i = 0; i < MAX_NUM_CHANNELS; i++ )
+    {
+        vecpChanFader[i]->SetDisplayChannelLevel ( bDisplayChannelLevels );
+    }
+}
+
 void CAudioMixerBoard::HideAll()
 {
     // make all controls invisible
@@ -710,6 +761,9 @@ void CAudioMixerBoard::ApplyNewConClientList ( CVector<CChannelInfo>& vecChanInf
                     }
                 }
 
+                // At some future time a new level will arrive -- ???
+                vecpChanFader[i]->SetChannelLevel ( 0 );
+
                 // set the text in the fader
                 vecpChanFader[i]->SetText ( vecChanInfo[j] );
 
@@ -857,3 +911,17 @@ bool CAudioMixerBoard::GetStoredFaderSettings ( const CChannelInfo& ChanInfo,
     // return "not OK" since we did not find matching fader settings
     return false;
 }
+
+void CAudioMixerBoard::SetChannelLevels ( const CVector<uint16_t>& vecChannelLevel )
+{
+    const int iNumChannelLevels = vecChannelLevel.Size();
+    int i = 0;
+
+    for ( int iChId = 0; iChId < MAX_NUM_CHANNELS; iChId++ )
+    {
+        if ( vecpChanFader[iChId]->IsVisible() && i < iNumChannelLevels )
+        {
+            vecpChanFader[iChId]->SetChannelLevel ( vecChannelLevel[i++] );
+        }
+    }
+}

src/audiomixerboard.h

@@ -36,6 +36,7 @@
 #include <QHostAddress>
 #include "global.h"
 #include "util.h"
+#include "multicolorledbar.h"
 
 
 /* Classes ********************************************************************/
@@ -55,6 +56,7 @@ public:
     bool IsSolo() { return pcbSolo->isChecked(); }
     bool IsMute() { return pcbMute->isChecked(); }
     void SetGUIDesign ( const EGUIDesign eNewDesign );
+    void SetDisplayChannelLevel ( const bool eNDCL );
 
     void UpdateSoloState ( const bool bNewOtherSoloState );
     void SetFaderLevel ( const int iLevel );
@@ -62,6 +64,7 @@ public:
     void SetFaderIsMute ( const bool bIsMute );
     int  GetFaderLevel() { return pFader->value(); }
     void Reset();
+    void SetChannelLevel ( const uint16_t iLevel );
 
 protected:
     double CalcFaderGain ( const int value );
@@ -69,18 +72,24 @@ protected:
     void   SendFaderLevelToServer ( const int iLevel );
     void   SetupFaderTag ( const ESkillLevel eSkillLevel );
 
-    QFrame*    pFrame;
+    QFrame*            pFrame;
-    QGroupBox* pLabelInstBox;
-    QSlider*   pFader;
-    QCheckBox* pcbMute;
-    QCheckBox* pcbSolo;
-    QLabel*    plblLabel;
-    QLabel*    plblInstrument;
-    QLabel*    plblCountryFlag;
 
-    QString    strReceivedName;
+    QWidget*           pLevelsBox;
+    QWidget*           pMuteSoloBox;
+    CMultiColorLEDBar* plbrChannelLevel;
+    QSlider*           pFader;
 
-    bool       bOtherChannelIsSolo;
+    QCheckBox*         pcbMute;
+    QCheckBox*         pcbSolo;
+
+    QGroupBox*         pLabelInstBox;
+    QLabel*            plblLabel;
+    QLabel*            plblInstrument;
+    QLabel*            plblCountryFlag;
+
+    QString            strReceivedName;
+
+    bool               bOtherChannelIsSolo;
 
 public slots:
     void OnLevelValueChanged ( int value ) { SendFaderLevelToServer ( value ); }
@@ -103,10 +112,13 @@ public:
     void ApplyNewConClientList ( CVector<CChannelInfo>& vecChanInfo );
     void SetServerName ( const QString& strNewServerName );
     void SetGUIDesign ( const EGUIDesign eNewDesign );
+    void SetDisplayChannelLevels ( const bool eNDCL );
 
     void SetFaderLevel ( const int iChannelIdx,
                          const int iValue );
 
+    void SetChannelLevels ( const CVector<uint16_t>& vecChannelLevel );
+
     // settings
     CVector<QString> vecStoredFaderTags;
     CVector<int>     vecStoredFaderLevels;
@@ -129,6 +141,7 @@ protected:
     CVector<CChannelFader*> vecpChanFader;
     QGroupBox*              pGroupBox;
     QHBoxLayout*            pMainLayout;
+    bool                    bDisplayChannelLevels;
     bool                    bNoFaderVisible;
 
 public slots:

src/channel.cpp

@@ -102,6 +102,10 @@ qRegisterMetaType<CHostAddress> ( "CHostAddress" );
     QObject::connect( &Protocol,
         SIGNAL ( LicenceRequired ( ELicenceType ) ),
         SIGNAL ( LicenceRequired ( ELicenceType ) ) );
+
+    QObject::connect ( &Protocol,
+        SIGNAL ( ReqChannelLevelList ( bool ) ),
+        this, SLOT ( OnReqChannelLevelList ( bool ) ) );
 }
 
 bool CChannel::ProtocolIsEnabled()

src/channel.h

@@ -159,12 +159,18 @@ public:
     void CreateReqConnClientsList()                          { Protocol.CreateReqConnClientsList(); }
     void CreateChatTextMes ( const QString& strChatText )    { Protocol.CreateChatTextMes ( strChatText ); }
     void CreateLicReqMes ( const ELicenceType eLicenceType ) { Protocol.CreateLicenceRequiredMes ( eLicenceType ); }
+    void CreateReqChannelLevelListMes ( bool bOptIn )        { Protocol.CreateReqChannelLevelListMes ( bOptIn ); }
 
     void CreateConClientListMes ( const CVector<CChannelInfo>& vecChanInfo )
         { Protocol.CreateConClientListMes ( vecChanInfo ); }
 
     CNetworkTransportProps GetNetworkTransportPropsFromCurrentSettings();
 
+    bool ChannelLevelsRequired() const                { return bChannelLevelsRequired; }
+
+    double GetPrevLevel() const              { return dPrevLevel; }
+    void   SetPrevLevel ( const double nPL ) { dPrevLevel = nPL; }
+
 protected:
     bool ProtocolIsEnabled();
 
@@ -177,6 +183,8 @@ protected:
         iNetwFrameSizeFact    = FRAME_SIZE_FACTOR_PREFERRED;
         iNetwFrameSize        = CELT_MINIMUM_NUM_BYTES;
         iNumAudioChannels     = 1; // mono
+
+        dPrevLevel            = 0.0;
     }
 
     // connection parameters
@@ -216,6 +224,9 @@ protected:
     QMutex            MutexSocketBuf;
     QMutex            MutexConvBuf;
 
+    bool              bChannelLevelsRequired;
+    double            dPrevLevel;
+
 public slots:
     void OnSendProtMessage ( CVector<uint8_t> vecMessage );
     void OnJittBufSizeChange ( int iNewJitBufSize );
@@ -249,6 +260,8 @@ public slots:
 
     void OnNewConnection() { emit NewConnection(); }
 
+    void OnReqChannelLevelList ( bool bOptIn ) { bChannelLevelsRequired = bOptIn; }
+
 signals:
     void MessReadyForSending ( CVector<uint8_t> vecMessage );
     void NewConnection();

src/client.cpp

@@ -65,6 +65,7 @@ CClient::CClient ( const quint16  iPortNumber,
     bFraSiFactDefSupported           ( false ),
     bFraSiFactSafeSupported          ( false ),
     eGUIDesign                       ( GD_ORIGINAL ),
+    bDisplayChannelLevels            ( true ),
     bJitterBufferOK                  ( true ),
     strCentralServerAddress          ( "" ),
     bUseDefaultCentralServerAddress  ( true ),
@@ -191,6 +192,10 @@ CClient::CClient ( const quint16  iPortNumber,
         SIGNAL ( CLVersionAndOSReceived ( CHostAddress, COSUtil::EOpSystemType, QString ) ) );
 #endif
 
+    QObject::connect ( &ConnLessProtocol,
+        SIGNAL ( CLChannelLevelListReceived ( CHostAddress, CVector<uint16_t> ) ),
+        this, SLOT ( OnCLChannelLevelListReceived ( CHostAddress, CVector<uint16_t> ) ) );
+
     // other
     QObject::connect ( &Sound, SIGNAL ( ReinitRequest ( int ) ),
         this, SLOT ( OnSndCrdReinitRequest ( int ) ) );
@@ -279,6 +284,9 @@ void CClient::OnNewConnection()
     // Same problem is with the jitter buffer message.
     Channel.CreateReqConnClientsList();
     CreateServerJitterBufferMessage();
+
+    // send opt-in / out for Channel Level updates
+    Channel.CreateReqChannelLevelListMes ( bDisplayChannelLevels );
 }
 
 void CClient::CreateServerJitterBufferMessage()
@@ -387,6 +395,14 @@ bool CClient::GetAndResetbJitterBufferOKFlag()
     return bSocketJitBufOKFlag;
 }
 
+void CClient::SetDisplayChannelLevels ( const bool bNDCL )
+{
+    bDisplayChannelLevels = bNDCL;
+
+    // tell any connected server about the change
+    Channel.CreateReqChannelLevelListMes ( bDisplayChannelLevels );
+}
+
 void CClient::SetSndCrdPrefFrameSizeFactor ( const int iNewFactor )
 {
     // first check new input parameter
@@ -598,6 +614,12 @@ void CClient::OnSndCrdReinitRequest ( int iSndCrdResetType )
     }
 }
 
+void CClient::OnCLChannelLevelListReceived ( CHostAddress      InetAddr,
+                                             CVector<uint16_t> vecLevelList )
+{
+    emit CLChannelLevelListReceived ( InetAddr, vecLevelList );
+}
+
 void CClient::Start()
 {
     // always use the OPUS codec

src/client.h

@@ -128,6 +128,9 @@ public:
     EGUIDesign GetGUIDesign() const { return eGUIDesign; }
     void SetGUIDesign ( const EGUIDesign eNGD ) { eGUIDesign = eNGD; }
 
+    bool GetDisplayChannelLevels() const { return bDisplayChannelLevels; }
+    void SetDisplayChannelLevels ( const bool bNDCL );
+
     EAudioQuality GetAudioQuality() const { return eAudioQuality; }
     void SetAudioQuality ( const EAudioQuality eNAudioQuality );
 
@@ -359,6 +362,7 @@ protected:
     int                     iStereoBlockSizeSam;
 
     EGUIDesign              eGUIDesign;
+    bool                    bDisplayChannelLevels;
 
     bool                    bJitterBufferOK;
 
@@ -398,6 +402,9 @@ public slots:
 
     void OnSndCrdReinitRequest ( int iSndCrdResetType );
 
+    void OnCLChannelLevelListReceived ( CHostAddress      InetAddr,
+                                        CVector<uint16_t> vecLevelList );
+
 signals:
     void ConClientListMesReceived ( CVector<CChannelInfo> vecChanInfo );
     void ChatTextReceived ( QString strChatText );
@@ -420,6 +427,9 @@ signals:
                                   QString                strVersion );
 #endif
 
+    void CLChannelLevelListReceived ( CHostAddress      InetAddr,
+                                      CVector<uint16_t> vecLevelList );
+
     void Disconnected();
     void ControllerInFaderLevel ( int iChannelIdx, int iValue );
 };

src/clientdlg.cpp

@@ -185,6 +185,9 @@ CClientDlg::CClientDlg ( CClient*        pNCliP,
     // reset mixer board
     MainMixerBoard->HideAll();
 
+    // restore channel level display preference
+    MainMixerBoard->SetDisplayChannelLevels ( pClient->GetDisplayChannelLevels() );
+
     // restore fader settings
     MainMixerBoard->vecStoredFaderTags   = pClient->vecStoredFaderTags;
     MainMixerBoard->vecStoredFaderLevels = pClient->vecStoredFaderLevels;
@@ -483,6 +486,10 @@ CClientDlg::CClientDlg ( CClient*        pNCliP,
         SIGNAL ( ControllerInFaderLevel ( int, int ) ),
         this, SLOT ( OnControllerInFaderLevel ( int, int ) ) );
 
+    QObject::connect ( pClient,
+        SIGNAL ( CLChannelLevelListReceived ( CHostAddress, CVector<uint16_t> ) ),
+        this, SLOT ( OnCLChannelLevelListReceived ( CHostAddress, CVector<uint16_t> ) ) );
+
 #ifdef ENABLE_CLIENT_VERSION_AND_OS_DEBUGGING
     QObject::connect ( pClient,
         SIGNAL ( CLVersionAndOSReceived ( CHostAddress, COSUtil::EOpSystemType, QString ) ),
@@ -495,6 +502,9 @@ CClientDlg::CClientDlg ( CClient*        pNCliP,
     QObject::connect ( &ClientSettingsDlg, SIGNAL ( GUIDesignChanged() ),
         this, SLOT ( OnGUIDesignChanged() ) );
 
+    QObject::connect ( &ClientSettingsDlg, SIGNAL ( DisplayChannelLevelsChanged() ),
+        this, SLOT ( OnDisplayChannelLevelsChanged() ) );
+
     QObject::connect ( &ClientSettingsDlg, SIGNAL ( AudioChannelsChanged() ),
         this, SLOT ( OnAudioChannelsChanged() ) );
 
@@ -906,7 +916,7 @@ void CClientDlg::OnTimerSigMet()
     // linear transformation of the input level range to the progress-bar
     // range
     dCurSigLevelL -= LOW_BOUND_SIG_METER;
-    dCurSigLevelL *= NUM_STEPS_INP_LEV_METER /
+    dCurSigLevelL *= NUM_STEPS_LED_BAR /
         ( UPPER_BOUND_SIG_METER - LOW_BOUND_SIG_METER );
 
     // lower bound the signal
@@ -916,7 +926,7 @@ void CClientDlg::OnTimerSigMet()
     }
 
     dCurSigLevelR -= LOW_BOUND_SIG_METER;
-    dCurSigLevelR *= NUM_STEPS_INP_LEV_METER /
+    dCurSigLevelR *= NUM_STEPS_LED_BAR /
         ( UPPER_BOUND_SIG_METER - LOW_BOUND_SIG_METER );
 
     // lower bound the signal

src/clientdlg.h

@@ -60,10 +60,6 @@
 #define BUFFER_LED_UPDATE_TIME_MS   300   // ms
 #define LED_BAR_UPDATE_TIME_MS      1000  // ms
 
-// range for signal level meter
-#define LOW_BOUND_SIG_METER         ( -50.0 ) // dB
-#define UPPER_BOUND_SIG_METER       ( 0.0 )   // dB
-
 // number of ping times > upper bound until error message is shown
 #define NUM_HIGH_PINGS_UNTIL_ERROR  5
 
@@ -196,12 +192,19 @@ public slots:
                                           CVector<CChannelInfo> vecChanInfo )
         { ConnectDlg.SetConnClientsList ( InetAddr, vecChanInfo ); }
 
+    void OnCLChannelLevelListReceived ( CHostAddress       /* unused */,
+                                        CVector<uint16_t> vecLevelList )
+        { MainMixerBoard->SetChannelLevels ( vecLevelList ); }
+
     void OnConnectDlgAccepted();
     void OnDisconnected();
 
     void OnGUIDesignChanged()
         { SetGUIDesign ( pClient->GetGUIDesign() ); }
 
+    void OnDisplayChannelLevelsChanged()
+        { MainMixerBoard->SetDisplayChannelLevels ( pClient->GetDisplayChannelLevels() ); }
+
     void OnAudioChannelsChanged() { UpdateRevSelection(); }
     void OnNumClientsChanged ( int iNewNumClients );
     void OnNewClientLevelChanged() { MainMixerBoard->iNewClientFaderLevel = pClient->iNewClientFaderLevel; }

src/clientsettingsdlg.cpp

@@ -189,6 +189,12 @@ CClientSettingsDlg::CClientSettingsDlg ( CClient* pNCliP, QWidget* parent,
 
     chbGUIDesignFancy->setAccessibleName ( tr ( "Fancy skin check box" ) );
 
+    // display channel levels
+    chbDisplayChannelLevels->setWhatsThis ( tr ( "<b>Display Channel Levels:</b> "
+        "If enabled, each client channel will display a pre-fader level bar." ) );
+
+    chbDisplayChannelLevels->setAccessibleName ( tr ( "Display channel levels check box" ) );
+
     // audio channels
     QString strAudioChannels = tr ( "<b>Audio Channels:</b> "
         "Select the number of audio channels to be used. There are three "
@@ -323,6 +329,9 @@ CClientSettingsDlg::CClientSettingsDlg ( CClient* pNCliP, QWidget* parent,
         chbGUIDesignFancy->setCheckState ( Qt::Checked );
     }
 
+    //  Display Channel Levels check box
+    chbDisplayChannelLevels->setCheckState ( pClient->GetDisplayChannelLevels() ? Qt::Checked : Qt::Unchecked );
+
     // "Audio Channels" combo box
     cbxAudioChannels->clear();
     cbxAudioChannels->addItem ( "Mono" );               // CC_MONO
@@ -386,6 +395,9 @@ CClientSettingsDlg::CClientSettingsDlg ( CClient* pNCliP, QWidget* parent,
     QObject::connect ( chbGUIDesignFancy, SIGNAL ( stateChanged ( int ) ),
         this, SLOT ( OnGUIDesignFancyStateChanged ( int ) ) );
 
+    QObject::connect ( chbDisplayChannelLevels, SIGNAL ( stateChanged ( int ) ),
+        this, SLOT ( OnDisplayChannelLevelsStateChanged ( int ) ) );
+
     QObject::connect ( chbAutoJitBuf, SIGNAL ( stateChanged ( int ) ),
         this, SLOT ( OnAutoJitBufStateChanged ( int ) ) );
 
@@ -704,6 +716,12 @@ void CClientSettingsDlg::OnGUIDesignFancyStateChanged ( int value )
     UpdateDisplay();
 }
 
+void CClientSettingsDlg::OnDisplayChannelLevelsStateChanged ( int value )
+{
+    pClient->SetDisplayChannelLevels ( value != Qt::Unchecked );
+    emit DisplayChannelLevelsChanged();
+}
+
 void CClientSettingsDlg::OnDefaultCentralServerStateChanged ( int value )
 {
     // apply new setting to the client

src/clientsettingsdlg.h

@@ -90,6 +90,7 @@ protected:
     void OnSliderSndCrdBufferDelay ( int value );
     void OnAutoJitBufStateChanged ( int value );
     void OnGUIDesignFancyStateChanged ( int value );
+    void OnDisplayChannelLevelsStateChanged ( int value );
     void OnDefaultCentralServerStateChanged ( int value );
     void OnCentralServerAddressEditingFinished();
     void OnNewClientLevelEditingFinished();
@@ -105,6 +106,7 @@ protected:
 
 signals:
     void GUIDesignChanged();
+    void DisplayChannelLevelsChanged();
     void AudioChannelsChanged();
     void NewClientLevelChanged();
 };

src/clientsettingsdlgbase.ui

@@ -530,11 +530,22 @@
        </layout>
       </item>
       <item>
-       <widget class="QCheckBox" name="chbGUIDesignFancy">
+       <layout class="QHBoxLayout">
-        <property name="text">
+        <item>
-         <string>Fancy Skin</string>
+         <widget class="QCheckBox" name="chbGUIDesignFancy">
-        </property>
+          <property name="text">
-       </widget>
+           <string>Fancy Skin</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QCheckBox" name="chbDisplayChannelLevels">
+          <property name="text">
+           <string>Display Channel Levels</string>
+          </property>
+         </widget>
+        </item>
+       </layout>
       </item>
       <item>
        <layout class="QHBoxLayout">
@@ -719,6 +730,7 @@
   <tabstop>cbxAudioQuality</tabstop>
   <tabstop>edtNewClientLevel</tabstop>
   <tabstop>chbGUIDesignFancy</tabstop>
+  <tabstop>chbDisplayChannelFaders</tabstop>
   <tabstop>chbDefaultCentralServer</tabstop>
   <tabstop>edtCentralServerAddress</tabstop>
  </tabstops>

src/global.h

@@ -169,10 +169,14 @@ LED bar:      lbr
 // maximum number of fader settings to be stored (together with the fader tags)
 #define MAX_NUM_STORED_FADER_SETTINGS   100
 
-// defines for LED input level meter
+// defines for LED level meter CMultiColorLEDBar
-#define NUM_STEPS_INP_LEV_METER         8
+#define NUM_STEPS_LED_BAR               8
-#define RED_BOUND_INP_LEV_METER         7
+#define RED_BOUND_LED_BAR               7
-#define YELLOW_BOUND_INP_LEV_METER      5
+#define YELLOW_BOUND_LED_BAR            5
+
+// range for signal level meter
+#define LOW_BOUND_SIG_METER         ( -50.0 ) // dB
+#define UPPER_BOUND_SIG_METER       ( 0.0 )   // dB
 
 // Maximum number of connected clients at the server. If you want to change this
 // paramter you have to modify the code on some places, too! The code tag
@@ -195,6 +199,9 @@ LED bar:      lbr
 // list
 #define PING_UPDATE_TIME_SERVER_LIST_MS 2000 // ms
 
+// defines the interval between Channel Level updates from the server
+#define CHANNEL_LEVEL_UPDATE_INTERVAL   100  // number of frames
+
 // time-out until a registered server is deleted from the server list if no
 // new registering was made in minutes
 #define SERVLIST_TIME_OUT_MINUTES       60 // minutes

src/multicolorledbar.cpp

@@ -33,7 +33,7 @@ CMultiColorLEDBar::CMultiColorLEDBar ( QWidget* parent, Qt::WindowFlags f )
     : QFrame ( parent, f )
 {
     // set total number of LEDs
-    iNumLEDs = NUM_STEPS_INP_LEV_METER;
+    iNumLEDs = NUM_STEPS_LED_BAR;
 
     // create layout and set spacing to zero
     pMainLayout = new QVBoxLayout ( this );
@@ -105,14 +105,14 @@ void CMultiColorLEDBar::setValue ( const int value )
             if ( iLEDIdx < value )
             {
                 // check which color we should use (green, yellow or red)
-                if ( iLEDIdx < YELLOW_BOUND_INP_LEV_METER )
+                if ( iLEDIdx < YELLOW_BOUND_LED_BAR )
                 {
                     // green region
                     vecpLEDs[iLEDIdx]->setColor ( cLED::RL_GREEN );
                 }
                 else
                 {
-                    if ( iLEDIdx < RED_BOUND_INP_LEV_METER )
+                    if ( iLEDIdx < RED_BOUND_LED_BAR )
                     {
                         // yellow region
                         vecpLEDs[iLEDIdx]->setColor ( cLED::RL_YELLOW );

src/protocol.cpp

@@ -153,6 +153,14 @@ MESSAGES (with connection)
     | 1 byte licence type |
     +---------------------+
 
+- PROTMESSID_CLM_REQ_CHANNEL_LEVEL_LIST: Opt in or out of the channel level list
+
+    +---------------+
+    | 1 byte option |
+    +---------------+
+
+    option is boolean, true to opt in, false to opt out
+
 
 // #### COMPATIBILITY OLD VERSION, TO BE REMOVED ####
 - PROTMESSID_OPUS_SUPPORTED: Informs that OPUS codec is supported
@@ -276,6 +284,27 @@ CONNECTION LESS MESSAGES
 
     note: does not have any data -> n = 0
 
+- PROTMESSID_CLM_CHANNEL_LEVEL_LIST: The channel level list
+
+    +----------------------------------+
+    | ( ( n + 1 ) / 2 ) * 4 bit values |
+    +----------------------------------+
+
+    n is number of connected clients
+
+    the values are the maximum channel levels for a client frame converted
+    to the range of CMultiColorLEDBar in 4 bits, two entries per byte
+    with the earlier channel in the lower half of the byte
+
+    where an odd number of clients is connected, there will be four unused
+    upper bits in the final byte, containing 0xF (which is out of range)
+
+    the server may compute them message when any client has used
+    PROTMESSID_CLM_REQ_CHANNEL_LEVEL_LIST to opt in
+
+    the server may issue to message only to a client that has used
+    PROTMESSID_CLM_REQ_CHANNEL_LEVEL_LIST to opt in
+
 
  ******************************************************************************
  *
@@ -549,6 +578,10 @@ if ( rand() < ( RAND_MAX / 2 ) ) return false;
             case PROTMESSID_LICENCE_REQUIRED:
                 bRet = EvaluateLicenceRequiredMes ( vecbyMesBodyData );
                 break;
+
+            case PROTMESSID_REQ_CHANNEL_LEVEL_LIST:
+                bRet = EvaluateReqChannelLevelListMes ( vecbyMesBodyData );
+                break;
             }
 
             // immediately send acknowledge message
@@ -634,6 +667,10 @@ if ( rand() < ( RAND_MAX / 2 ) ) return false;
         case PROTMESSID_CLM_REQ_CONN_CLIENTS_LIST:
             bRet = EvaluateCLReqConnClientsListMes ( InetAddr );
             break;
+
+        case PROTMESSID_CLM_CHANNEL_LEVEL_LIST:
+            bRet = EvaluateCLChannelLevelListMes ( InetAddr, vecbyMesBodyData );
+            break;
         }
     }
     else
@@ -1234,6 +1271,40 @@ void CProtocol::CreateOpusSupportedMes()
                            CVector<uint8_t> ( 0 ) );
 }
 
+void CProtocol::CreateReqChannelLevelListMes ( const bool bRCL )
+{
+    CVector<uint8_t> vecData ( 1 ); // 1 byte of data
+    int              iPos = 0; // init position pointer
+    PutValOnStream ( vecData, iPos,
+        static_cast<uint32_t> ( bRCL ), 1 );
+
+    CreateAndSendMessage ( PROTMESSID_REQ_CHANNEL_LEVEL_LIST, vecData );
+}
+
+bool CProtocol::EvaluateReqChannelLevelListMes ( const CVector<uint8_t>& vecData )
+{
+    int iPos = 0; // init position pointer
+
+    // check size
+    if ( vecData.Size() != 1 )
+    {
+        return true; // return error code
+    }
+
+    // extract opt in / out for channel levels
+    uint32_t val = GetValFromStream ( vecData, iPos, 1 );
+
+    if ( val != 0 && val != 1 )
+    {
+        return true; // return error code
+    }
+
+    // invoke message action
+    emit ReqChannelLevelList ( static_cast<bool> ( val ) );
+
+    return false; // no error
+}
+
 
 // Connection less messages ----------------------------------------------------
 void CProtocol::CreateCLPingMes ( const CHostAddress& InetAddr, const int iMs )
@@ -1936,6 +2007,70 @@ bool CProtocol::EvaluateCLReqConnClientsListMes ( const CHostAddress& InetAddr )
     return false; // no error
 }
 
+void CProtocol::CreateCLChannelLevelListMes  ( const CHostAddress&      InetAddr,
+                                               const CVector<uint16_t>& vecLevelList,
+                                               const int                iNumClients )
+{
+    // This must be a multiple of bytes at four bits per client
+    const int        iNumBytes = ( iNumClients + 1 ) / 2;
+    CVector<uint8_t> vecData( iNumBytes );
+    int              iPos = 0; // init position pointer
+
+    for ( int i = 0, j = 0; i < iNumClients; i += 2 /* pack two per byte */, j++ )
+    {
+        uint16_t levelLo = vecLevelList[i] & 0x0F;
+        uint16_t levelHi = ( i + 1 < iNumClients ) ? vecLevelList[i + 1] & 0x0F : 0x0F;
+        uint8_t  byte    = static_cast<uint8_t> ( levelLo | ( levelHi << 4 ) );
+
+        PutValOnStream ( vecData, iPos,
+            static_cast<uint32_t> ( byte ), 1 );
+    }
+
+    CreateAndImmSendConLessMessage ( PROTMESSID_CLM_CHANNEL_LEVEL_LIST,
+                                     vecData,
+                                     InetAddr );
+}
+
+bool CProtocol::EvaluateCLChannelLevelListMes  ( const CHostAddress&     InetAddr,
+                                                 const CVector<uint8_t>& vecData )
+{
+    int       iPos     = 0; // init position pointer
+    const int iDataLen = vecData.Size();  // four bits per channel, 2 channels per byte
+                                          // may have one too many entries, last being 0xF
+    int       iVecLen  = iDataLen * 2; // one ushort per channel
+
+    if ( iVecLen > MAX_NUM_CHANNELS )
+    {
+        return true; // return error code
+    }
+
+    CVector<uint16_t> vecLevelList ( iVecLen );
+
+    for (int i = 0, j = 0; i < iDataLen; i++, j += 2 )
+    {
+        uint8_t  byte    = static_cast<uint8_t> ( GetValFromStream ( vecData, iPos, 1 ) );
+        uint16_t levelLo = byte & 0x0F;
+        uint16_t levelHi = ( byte >> 4 ) & 0x0F;
+
+        vecLevelList[j]     = levelLo;
+
+        if ( levelHi != 0x0F )
+        {
+            vecLevelList[j + 1] = levelHi;
+        }
+        else
+        {
+            vecLevelList.resize ( iVecLen - 1 );
+            break;
+        }
+    }
+
+    // invoke message action
+    emit CLChannelLevelListReceived ( InetAddr, vecLevelList );
+
+    return false; // no error
+}
+
 
 /******************************************************************************\
 * Message generation and parsing                                               *

src/protocol.h

@@ -54,6 +54,7 @@
 #define PROTMESSID_CHANNEL_INFOS              25 // set channel infos
 #define PROTMESSID_OPUS_SUPPORTED             26 // tells that OPUS codec is supported
 #define PROTMESSID_LICENCE_REQUIRED           27 // licence required
+#define PROTMESSID_REQ_CHANNEL_LEVEL_LIST     28 // request the channel level list
 
 // message IDs of connection less messages (CLM)
 // DEFINITION -> start at 1000, end at 1999, see IsConnectionLessMessageID
@@ -71,6 +72,7 @@
 #define PROTMESSID_CLM_REQ_VERSION_AND_OS     1012 // request version number and operating system
 #define PROTMESSID_CLM_CONN_CLIENTS_LIST      1013 // channel infos for connected clients
 #define PROTMESSID_CLM_REQ_CONN_CLIENTS_LIST  1014 // request the connected clients list
+#define PROTMESSID_CLM_CHANNEL_LEVEL_LIST     1015 // channel level list
 
 // lengths of message as defined in protocol.cpp file
 #define MESS_HEADER_LENGTH_BYTE         7 // TAG (2), ID (2), cnt (1), length (2)
@@ -102,6 +104,7 @@ public:
     void CreateReqNetwTranspPropsMes();
     void CreateLicenceRequiredMes ( const ELicenceType eLicenceType );
     void CreateOpusSupportedMes();
+    void CreateReqChannelLevelListMes ( const bool bRCL );
 
     void CreateCLPingMes               ( const CHostAddress& InetAddr, const int iMs );
     void CreateCLPingWithNumClientsMes ( const CHostAddress& InetAddr,
@@ -123,6 +126,9 @@ public:
     void CreateCLConnClientsListMes    ( const CHostAddress&          InetAddr,
                                          const CVector<CChannelInfo>& vecChanInfo );
     void CreateCLReqConnClientsListMes ( const CHostAddress& InetAddr );
+    void CreateCLChannelLevelListMes   ( const CHostAddress&      InetAddr,
+                                         const CVector<uint16_t>& vecLevelList,
+                                         const int                iNumClients );
 
     static bool ParseMessageFrame ( const CVector<uint8_t>& vecbyData,
                                     const int               iNumBytesIn,
@@ -205,17 +211,18 @@ protected:
                                           const CVector<uint8_t>& vecData,
                                           const CHostAddress&     InetAddr );
 
-    bool EvaluateJitBufMes            ( const CVector<uint8_t>& vecData );
+    bool EvaluateJitBufMes              ( const CVector<uint8_t>& vecData );
     bool EvaluateReqJitBufMes();
-    bool EvaluateChanGainMes          ( const CVector<uint8_t>& vecData );
+    bool EvaluateChanGainMes            ( const CVector<uint8_t>& vecData );
-    bool EvaluateConClientListMes     ( const CVector<uint8_t>& vecData );
+    bool EvaluateConClientListMes       ( const CVector<uint8_t>& vecData );
     bool EvaluateReqConnClientsList();
-    bool EvaluateChanInfoMes          ( const CVector<uint8_t>& vecData );
+    bool EvaluateChanInfoMes            ( const CVector<uint8_t>& vecData );
     bool EvaluateReqChanInfoMes();
-    bool EvaluateChatTextMes          ( const CVector<uint8_t>& vecData );
+    bool EvaluateChatTextMes            ( const CVector<uint8_t>& vecData );
-    bool EvaluateNetwTranspPropsMes   ( const CVector<uint8_t>& vecData );
+    bool EvaluateNetwTranspPropsMes     ( const CVector<uint8_t>& vecData );
     bool EvaluateReqNetwTranspPropsMes();
-    bool EvaluateLicenceRequiredMes   ( const CVector<uint8_t>& vecData );
+    bool EvaluateLicenceRequiredMes     ( const CVector<uint8_t>& vecData );
+    bool EvaluateReqChannelLevelListMes ( const CVector<uint8_t>& vecData );
 
     bool EvaluateCLPingMes               ( const CHostAddress&     InetAddr,
                                            const CVector<uint8_t>& vecData );
@@ -236,6 +243,8 @@ protected:
     bool EvaluateCLConnClientsListMes    ( const CHostAddress&     InetAddr,
                                            const CVector<uint8_t>& vecData );
     bool EvaluateCLReqConnClientsListMes ( const CHostAddress&     InetAddr );
+    bool EvaluateCLChannelLevelListMes   ( const CHostAddress&     InetAddr,
+                                           const CVector<uint8_t>& vecData );
 
     int                     iOldRecID;
     int                     iOldRecCnt;
@@ -270,6 +279,7 @@ signals:
     void NetTranspPropsReceived ( CNetworkTransportProps NetworkTransportProps );
     void ReqNetTranspProps();
     void LicenceRequired ( ELicenceType eLicenceType );
+    void ReqChannelLevelList ( bool bOptIn );
 
     void CLPingReceived               ( CHostAddress           InetAddr,
                                         int                    iMs );
@@ -291,4 +301,6 @@ signals:
     void CLConnClientsListMesReceived ( CHostAddress           InetAddr,
                                         CVector<CChannelInfo>  vecChanInfo );
     void CLReqConnClientsList         ( CHostAddress           InetAddr );
+    void CLChannelLevelListReceived   ( CHostAddress           InetAddr,
+                                        CVector<uint16_t>      vecLevelList );
 };

src/res/homepage/manual.md

@@ -81,11 +81,11 @@ The reverberation effect requires significant CPU so that it should only be used
 level fader is set to minimum (which is the default setting), the reverberation effect is switched off and does
 not cause any additional CPU usage.
 
-### Local audio input fader
+### Local audio pan / balance control
 
-![Local audio input fader](audiofader.jpg)
+![Local audio pan / balance control](audiofader.jpg)
 
-With the audio fader, the relative levels of the left and right local audio channels can be changed. For a mono signal
+With the balance control, the relative levels of the left and right local audio channels can be changed. For a mono signal
 it acts like a panning between the two channels. If, e.g., a microphone is connected to the right input channel and
 an instrument is connected to the left input channel which is much louder than the microphone, move the audio fader
 in a direction where the label above the fader shows L -x, where x is the current attenuation indicator.
@@ -94,11 +94,13 @@ in a direction where the label above the fader shows L -x, where x is the curren
 
 ![Audio faders](faders.jpg)
 
-In the audio mixer frame, a fader for each connected client at the server is shown. This includes a fader for the own signal.
+In the audio mixer frame, a fader is shown for each connected client at the server, including yourself.
-With the faders, the audio level of each client can be modified individually.
+The faders allow you to adjust the level of what you hear without affecting what others hear.
+The VU meter shows the input level at the server - that is, what you are sending.
 
-With the Mute checkbox, the current audio channel can be muted. With the Solo checkbox, the current audio channel can
+Using the Mute checkbox prevents the indicated channel being heard in your local mix.
-be set to solo which means that all other channels except of the current channel are muted.
+
+The solo checkboxes allow you to hear only one, or several, channels, with those not soloed being muted.
 
 Settings Window
 ---------------
@@ -206,6 +208,12 @@ that client was already stored.
 
 If enabled, a fancy skin will be applied to the main window.
 
+### Display channel levels
+
+![Display channel levels](displaychannellevels.png)
+
+If enabled, the channel input level for each connected client will be displayed in the mixer.
+
 ### Central server address
 
 ![Central server address](centralserveraddress.png)

src/server.cpp

@@ -335,6 +335,8 @@ CServer::CServer ( const int          iNewMaxNumChan,
     // allocate worst case memory for the coded data
     vecbyCodedData.Init ( MAX_SIZE_BYTES_NETW_BUF );
 
+    // allocate worst case memory for the channel levels
+    vecChannelLevels.Init     ( iMaxNumChannels );
 
     // enable history graph (if requested)
     if ( !strHistoryFileName.isEmpty() )
@@ -864,6 +866,7 @@ JitterMeas.Measure();
     // some inits
     int  iNumClients               = 0; // init connected client counter
     bool bChannelIsNowDisconnected = false;
+    bool bSendChannelLevels        = false;
 
     // Make put and get calls thread safe. Do not forget to unlock mutex
     // afterwards!
@@ -1007,6 +1010,29 @@ JitterMeas.Measure();
     // one client is connected.
     if ( iNumClients > 0 )
     {
+
+        // Low frequency updates
+        if ( iFrameCount > CHANNEL_LEVEL_UPDATE_INTERVAL )
+        {
+            iFrameCount = 0;
+
+            // Calculate channel levels if any client has requested them
+            for ( int i = 0; i < iNumClients; i++ )
+            {
+                if ( vecChannels[ vecChanIDsCurConChan[i] ].ChannelLevelsRequired() )
+                {
+                    bSendChannelLevels = true;
+
+                    CreateLevelsForAllConChannels ( iNumClients,
+                                                    vecNumAudioChannels,
+                                                    vecvecsData,
+                                                    vecChannelLevels );
+                    break;
+                }
+            }
+        }
+        iFrameCount++;
+
         for ( int i = 0; i < iNumClients; i++ )
         {
             // get actual ID of current channel
@@ -1095,6 +1121,12 @@ opus_custom_encoder_ctl ( CurOpusEncoder,
 
             // update socket buffer size
             vecChannels[iCurChanID].UpdateSocketBufferSize();
+
+            // send channel levels
+            if ( bSendChannelLevels && vecChannels[iCurChanID].ChannelLevelsRequired() )
+            {
+                ConnLessProtocol.CreateCLChannelLevelListMes ( vecChannels[iCurChanID].GetAddress(), vecChannelLevels, iNumClients );
+            }
         }
     }
     else
@@ -1574,3 +1606,69 @@ void CServer::customEvent ( QEvent* pEvent )
         }
     }
 }
+
+/// @brief Compute frame peak level for each client
+void CServer::CreateLevelsForAllConChannels ( const int                        iNumClients,
+                                              const CVector<int>&              vecNumAudioChannels,
+                                              const CVector<CVector<int16_t> > vecvecsData,
+                                              CVector<uint16_t>&               vecLevelsOut )
+{
+    int i, j, k;
+
+    // init return vector with zeros since we mix all channels on that vector
+    vecLevelsOut.Reset ( 0 );
+
+    for ( j = 0; j < iNumClients; j++ )
+    {
+        // get a reference to the audio data
+        const CVector<int16_t>& vecsData = vecvecsData[j];
+
+        double dCurLevel = 0.0;
+        if ( vecNumAudioChannels[j] == 1 )
+        {
+            // mono
+            for ( i = 0; i < SYSTEM_FRAME_SIZE_SAMPLES; i += 3 )
+            {
+                dCurLevel = std::max ( dCurLevel, std::abs ( static_cast<double> ( vecsData[i] ) ) );
+            }
+        }
+        else
+        {
+            // stereo: apply stereo-to-mono attenuation
+            for ( i = 0, k = 0; i < SYSTEM_FRAME_SIZE_SAMPLES; i += 3, k += 6 )
+            {
+                double sMix = ( static_cast<double> ( vecsData[k] ) + vecsData[k + 1] ) / 2;
+                dCurLevel = std::max ( dCurLevel, std::abs ( sMix ) );
+            }
+        }
+
+        // smoothing
+        int iChId = vecChanIDsCurConChan [ j ];
+        dCurLevel = std::max ( dCurLevel, vecChannels[ iChId ].GetPrevLevel() * 0.5 );
+        vecChannels[ iChId ].SetPrevLevel ( dCurLevel );
+
+        // logarithmic measure
+        const double dNormChanLevel = dCurLevel / _MAXSHORT;
+        double dCurSigLevel;
+        if ( dNormChanLevel > 0 )
+        {
+            dCurSigLevel = 20.0 * log10 ( dNormChanLevel );
+        }
+        else
+        {
+            dCurSigLevel = -100000.0; // large negative value
+        }
+
+        // map to signal level meter
+        dCurSigLevel -= LOW_BOUND_SIG_METER;
+        dCurSigLevel *= NUM_STEPS_LED_BAR /
+            ( UPPER_BOUND_SIG_METER - LOW_BOUND_SIG_METER );
+
+        if ( dCurSigLevel < 0 )
+        {
+            dCurSigLevel = 0;
+        }
+
+        vecLevelsOut[j] = static_cast<uint16_t> ( ceil ( dCurSigLevel ) );
+    }
+}

src/server.h

@@ -28,6 +28,7 @@
 #include <QTimer>
 #include <QDateTime>
 #include <QHostAddress>
+#include <algorithm>
 #ifdef USE_OPUS_SHARED_LIB
 # include "opus/opus_custom.h"
 #else
@@ -225,6 +226,11 @@ protected:
     // if server mode is normal or double system frame size
     bool                       bUseDoubleSystemFrameSize;
 
+    void CreateLevelsForAllConChannels  ( const int                        iNumClients,
+                                          const CVector<int>&              vecNumAudioChannels,
+                                          const CVector<CVector<int16_t> > vecvecsData,
+                                          CVector<uint16_t>&               vecLevelsOut );
+
     // do not use the vector class since CChannel does not have appropriate
     // copy constructor/operator
     CChannel                   vecChannels[MAX_NUM_CHANNELS];
@@ -255,12 +261,18 @@ protected:
     CVector<int16_t>           vecsSendData;
     CVector<uint8_t>           vecbyCodedData;
 
+    // Channel levels
+    CVector<uint16_t>          vecChannelLevels;
+
     // actual working objects
     CHighPrioSocket            Socket;
 
     // logging
     CServerLogging             Logging;
 
+    // channel level update frame interval counter
+    uint16_t                   iFrameCount;
+
     // recording thread
     recorder::CJamRecorder     JamRecorder;
     bool                       bEnableRecording;

src/settings.cpp

@@ -250,6 +250,12 @@ void CSettings::Load()
             pClient->SetGUIDesign ( static_cast<EGUIDesign> ( iValue ) );
         }
 
+        // display channel levels preference
+        if ( GetFlagIniSet ( IniXMLDocument, "client", "displaychannellevels", bValue ) )
+        {
+            pClient->SetDisplayChannelLevels ( bValue );
+        }
+
         // audio channels
         if ( GetNumericIniSet ( IniXMLDocument, "client", "audiochannels",
              0, 2 /* CC_STEREO */, iValue ) )
@@ -490,6 +496,10 @@ void CSettings::Save()
         SetNumericIniSet ( IniXMLDocument, "client", "guidesign",
             static_cast<int> ( pClient->GetGUIDesign() ) );
 
+        // display channel levels preference
+        SetFlagIniSet ( IniXMLDocument, "client", "displaychannellevels",
+            pClient->GetDisplayChannelLevels() );
+
         // audio channels
         SetNumericIniSet ( IniXMLDocument, "client", "audiochannels",
             static_cast<int> ( pClient->GetAudioChannels() ) );