/*

* Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:  Comfort noise generator of MCC jitterbuffer

*

*/

// INCLUDE FILES

#include <mmcccodecinformation.h> //codec FourCC declarations

#include <voipjitterbufferintfc.h>

#include "debugtracemacros.h"

#include "InternalDef.h"

#include "JitterBufferObserver.h"

#include "CngGenerator.h"

// -----------------------------------------------------------------------------

// CVoIPCNGenerator::NewL

// Static constructor.

// -----------------------------------------------------------------------------

//

CVoIPCNGenerator* CVoIPCNGenerator::NewL(MJitterBufferObserver* aObserver,

                                         const TFourCC& aCodec)

    {

    CVoIPCNGenerator* self = new (ELeave) CVoIPCNGenerator(aObserver, aCodec);

    CleanupStack::PushL(self);

    self->ConstructL();

    CleanupStack::Pop(self);

    return self;

    }

// -----------------------------------------------------------------------------

// CVoIPCNGenerator::CVoIPCNGenerator

// C++ default constructor can NOT contain any code, that might leave.

// -----------------------------------------------------------------------------

//

CVoIPCNGenerator::CVoIPCNGenerator(MJitterBufferObserver* aObserver,

                                   const TFourCC& aCodec)

    {

    iObserver = aObserver;

    iCodec = aCodec;

    }

// -----------------------------------------------------------------------------

// CVoIPCNGenerator::ConstructL

// Symbian 2nd phase constructor can leave.

// -----------------------------------------------------------------------------

//

void CVoIPCNGenerator::ConstructL()

    {

    switch (iCodec.FourCC())

        {

        case KMccFourCCIdG711:

        case KMccFourCCIdG729:

        case KMccFourCCIdILBC:

        case KMccFourCCIdAMRNB:

            break;

        default:

            User::Leave(KErrNotSupported);

        }

    }

// -----------------------------------------------------------------------------

// CVoIPCNGenerator::~CVoIPCNGenerator

// Destructor

// -----------------------------------------------------------------------------

//

CVoIPCNGenerator::~CVoIPCNGenerator()

    {

    }

// -----------------------------------------------------------------------------

// CVoIPCNGenerator::CreateSidBufferL

// Creates codec-specific SID Buffer

// -----------------------------------------------------------------------------

//

void CVoIPCNGenerator::GenerateSidPacket(TDes8& aPayload, TInt aRequestSize)

    {

//    TRACE_PRN_FN_ENT;

    if (aRequestSize > aPayload.MaxLength())

        {

        TRACE_PRN_N(_L("CVoIPCNGenerator::GenerateSidPacket->Adjust Size"));

        aRequestSize = aPayload.MaxLength();

        }

    iGeneratedCNFrames++;

    TRACE_PRN_N1(_L("JB-CNG-> Generated CN frames [%d]"), iGeneratedCNFrames);

    if (iCodec.FourCC() == KMccFourCCIdAMRNB)

        {

        GenerateAmrNoDataPacket(aPayload);

        if (iGeneratedCNFrames == KAmrNbSidUpdateInterval)

            {

            // We haven't received SID_UPDATE for the 8-th frame;

            // this means packet loss

            iDtxPeriodStarted = EFalse;

            }

        }

    else

        {

        GenerateVoIPNoDataPacket(aPayload, aRequestSize);

        }

//    TRACE_PRN_FN_EXT;

    }

// -----------------------------------------------------------------------------

// CVoIPCNGenerator::GenerateAmrNoDataPacket

// Generates AMR SID packet

// -----------------------------------------------------------------------------

//

void CVoIPCNGenerator::GenerateAmrNoDataPacket(TDes8& aPayload) const

    {

//    TRACE_PRN_FN_ENT;

    if (aPayload.MaxLength() >= KNoDataLength)

        {

        aPayload.Copy(&KAmrNoDataFrame, KNoDataLength);

        }

//    TRACE_PRN_FN_EXT;

    };

// -----------------------------------------------------------------------------

// CVoIPCNGenerator::GenerateVoIPNoDataPacket

// Generates SID packet for codecs other than AMR

// -----------------------------------------------------------------------------

//

void CVoIPCNGenerator::GenerateVoIPNoDataPacket(TDes8& aPayload,

                                                TInt aRequestSize) const

    {

//    TRACE_PRN_FN_ENT;

    aPayload.FillZ(aRequestSize);

    if (!iDtxPeriodStarted)

        {

        ConcealErrorForNextFrame();

        }

//    TRACE_PRN_FN_EXT;

    };

// -----------------------------------------------------------------------------

// CVoIPCNGenerator::ConcealErrorForNextFrame

// Requests error concealment for the next frame

// -----------------------------------------------------------------------------

//

void CVoIPCNGenerator::ConcealErrorForNextFrame() const

    {

    iObserver->EventJB(MJitterBufferObserver::EConcealErrorForNextBuffer);

    }

// -----------------------------------------------------------------------------

// CVoIPCNGenerator::DtxPeriodStatus

// Returns DTX status

// -----------------------------------------------------------------------------

//

TBool CVoIPCNGenerator::DtxPeriodStatus() const

    {

    return iDtxPeriodStarted;

    }

// -----------------------------------------------------------------------------

// CVoIPCNGenerator::DoDtxDecision()

// Determine DTX period based on codec used and data in the buffer

// -----------------------------------------------------------------------------

//

void CVoIPCNGenerator::DoDtxDecision(const TDes8& aData)

    {

//    TRACE_PRN_FN_ENT;

    if (aData.Length() > KMinDataLenForDtx)

        {

        if (IsSidBuffer(aData))

            {

            // DTX period started or updated

            iDtxPeriodStarted = ETrue;

            iGeneratedCNFrames = 0;

            TRACE_PRN_N(_L("JB-CNG-> DTX_START"));

            }

        else

            {

            // DTX period has ended

            iDtxPeriodStarted = EFalse;

            TRACE_PRN_N(_L("JB-CNG-> DTX_END"));

            }

        }

//    TRACE_PRN_FN_EXT;

    }

// -----------------------------------------------------------------------------

// CVoIPCNGenerator::IsSidBuffer

// Is the given buffer a SID UPDATE buffer

// -----------------------------------------------------------------------------

//

TBool CVoIPCNGenerator::IsSidBuffer(const TDes8& aData)

    {

//    TRACE_PRN_FN_ENT;

    TBool status = ETrue;

    switch (iCodec.FourCC())

        {

        case KMccFourCCIdAMRNB:

            {

            // Get AMR mode by bit-masking first byte and shifting

            const TUint8 mode((aData[0] & KAmrModeMask) >> KModeShiftBits); 

            if (mode == KAmrSidMode)

                {

                status = ETrue;

                TRACE_PRN_N(_L("JB-CNG-> SID AMRNB FRAME"));

                }

            else

                {

                status = EFalse;

                TRACE_PRN_N(_L("JB-CNG-> NON-SID AMRNB FRAME"));

                }

            break;

            }

        case KMccFourCCIdG711:

        case KMccFourCCIdILBC:

        case KMccFourCCIdG729:

            {

            // Check the frame type

            if (aData[0] == KVoIPCNFrame)

                {

                status = ETrue;

                TRACE_PRN_N(_L("JB-CNG-> SID FRAME"));

                }

            else

                {

                status = EFalse;

                TRACE_PRN_N(_L("JB-CNG-> NON-SID FRAME"));

                }

            break;

            }

        default:

            {

            status = EFalse;

            TRACE_PRN_N(_L("JB-CNG-> SID-UNKNOWN"));

            }

        }

//    TRACE_PRN_FN_EXT;

    return status;

    }

//  End of File