/*

* 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:  Declares class for comfort noise generating utility (CNG)

*

*/

#ifndef CNGGENERATOR_H

#define CNGGENERATOR_H

#include <mmfutilities.h>

// FORWARD DECLARATIONS

class MJitterBufferObserver;

/**

 * Comfort noise generating utility

 *

 * @lib MMccJitterBuffer.lib

 * @since Series 60 5.0

 */

NONSHARABLE_CLASS (CVoIPCNGenerator) : public CBase

    {

public:  // Constructor and destructor

    /**

     * Two phased constructor

     */

    static CVoIPCNGenerator* NewL(MJitterBufferObserver* iObserver,

                                  const TFourCC& aCodec);

    /**

     * Destructor

     */

    virtual ~CVoIPCNGenerator();

public: // New functions

    /**

     * Generates an SID packet to given buffer

     * @since Series 60 5.0

     * @param aPayload Buffer to be filled with SID data

     * @param aRequestSize Amount of data to be generated to buffer.

     * @return void

     */

    void GenerateSidPacket(TDes8& aPayload, TInt aRequestSize);

    /**

     * Requests error concealment for the next frame.

     * @since Series 60 5.0

     * @param None

     * @return void

     */

    void ConcealErrorForNextFrame() const;

    /**

     * Returns current DTX status

     * @since Series 60 5.0

     * @param None

     * @return TBool ETrue if DTX period ongoing

     */

    TBool DtxPeriodStatus() const;

    /**

     * Decide whether we are in DTX period or in normal speech period

     * @since Series 60 5.0

     * @param const TDes8& - Buffer containing data

     * @return TInt

     */

    void DoDtxDecision(const TDes8& aPayload);

    /**

     * Checks whether buffer contains SID frame.

     * @since Series 60 5.0

     * @param const TDes8& - Buffer containing data

     * @return TBool - ETrue if buffer contains SID frame

     */

    TBool IsSidBuffer(const TDes8& aData);

private: // New functions

    /**

     * Generates an AMR CN packet into aPayload

     * @since Series 60 5.0

     * @param aPayload

     * @return void

     */

    void GenerateAmrNoDataPacket(TDes8& aPayload) const;

    /**

     * Generates an VoIP NO_DATA frame into aPayload

     * @since Series 60 5.0

     * @param aPayload Buffer to be filled with VoIP NO_DATA information

     * @param aRequestSize Amount of data to be generated to buffer.

     * @return void

     */

    void GenerateVoIPNoDataPacket(TDes8& aPayload, TInt aRequestSize) const;

private: //Constructors

    /**

     * C++ default constructor.

     */

    CVoIPCNGenerator(MJitterBufferObserver* iObserver, const TFourCC& aCodec);

    /**

     * Symbian 2nd phase constructor.

     */

    void ConstructL();

private:    // Data

    // Codec type

    TFourCC iCodec;

    // For Error Concealment IF creation

    MJitterBufferObserver* iObserver;

    // Generated CN frames

    TInt iGeneratedCNFrames;

    // DTX period started

    TBool iDtxPeriodStarted;

    };

#endif  // CNGGENERATOR_H

// End of file