1 /*

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

     3  * All rights reserved.

     4  * This component and the accompanying materials are made available

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

     6  * which accompanies this distribution, and is available

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

     8  *

     9  * Initial Contributors:

    10  * Nokia Corporation - initial contribution.

    11  *

    12  * Contributors:

    13  *

    14  * Description:  Jitter buffer for audio frames.

    15  *  Interface   : VoIPJitterBuffer.lib

    16  *

    17  */

    18 

    19 #ifndef __VOIPJITTERBUFFER_H

    20 #define __VOIPJITTERBUFFER_H

    21 

    22 // DATA TYPES

    23 

    24 // FORWARD DECLARATIONS

    25 class CMccCnGenerator;

    26 class CVoIPJitterBufferImpl;

    27 class TVoIPJBConfig;

    28 class MJitterBufferObserver;

    29 

    30 // CLASS DECLARATION

    31 

    32 /**

    33  *  Jitter buffer.

    34  *

    35  *  @lib VoIPJitterBuffer.lib

    36  *  @since Series 60 5.0

    37  */

    38 class CVoIPJitterBuffer : public CActive

    39     {

    40 private:

    41     /**

    42      * Jitter buffer states

    43      */

    44     enum TJBState

    45         {

    46         EJBufStopped,

    47         EJBufPlaying,

    48         EJBufPaused

    49         };

    50 

    51     /**

    52      * Transition states during JB playback

    53      */

    54     enum TJBTransitionState

    55         {

    56         EWait,

    57         //    ENeedData,

    58         EEmptyData

    59         };

    60 

    61 public:

    62     // Constructors and destructor

    63 

    64     /**

    65      * Two-phased constructor.

    66      */

    67     IMPORT_C static CVoIPJitterBuffer* NewL(MJitterBufferObserver* aObserver);

    68 

    69     /**

    70      * Destructor.

    71      */

    72     virtual ~CVoIPJitterBuffer();

    73 

    74 public:

    75     // Methods

    76 

    77     /**

    78      * SetupL

    79      * Sets codec information and initializes JB.

    80      * @since Series 60 5.0

    81      * @param TFourCC - codec's fourcc

    82      * @param TVoIPJBConfig& - JB configuraion parameters

    83      * @return void

    84      */

    85     IMPORT_C void SetupL(const TFourCC aCodec, const TVoIPJBConfig& aJBConfig);

    86 

    87     /**

    88      * ResetBuffer

    89      * Resets JB to its original state with no data.

    90      * @since Series 60 5.0

    91      * @param TBool - ETrue == tone is to be played

    92      * @return void

    93      */

    94     IMPORT_C void ResetBuffer(TBool aPlayTone = ETrue);

    95 

    96     /**

    97      * Delay Down

    98      *

    99      * @since Series 60 5.0

   100      * @param none

   101      * @return void

   102      */

   103     IMPORT_C void DelayDown();

   104 

   105     /**

   106      * Delay Up

   107      *

   108      * @since Series 60 5.0

   109      * @param none

   110      * @return void

   111      */

   112     IMPORT_C void DelayUp();

   113 

   114     /**

   115      * Play

   116      *

   117      * @since Series 60 5.0

   118      * @param none

   119      * @return void

   120      */

   121     IMPORT_C void Play();

   122 

   123     /**

   124      * Pause

   125      *

   126      * @since Series 60 5.0

   127      * @param none

   128      * @return void

   129      */

   130     IMPORT_C void Pause();

   131 

   132     /**

   133      * Stop

   134      *

   135      * @since Series 60 5.0

   136      * @param none

   137      * @return void

   138      */

   139     IMPORT_C void Stop();

   140 

   141     /**

   142      * FillBuffer

   143      * Retrieves next frame from JB queue.

   144      * @since Series 60 5.0

   145      * @param CMMFBuffer* - buffer to be filled with data from the JB

   146      * @return TInt

   147      */

   148     IMPORT_C TInt FillBuffer(CMMFBuffer* aBuffer);

   149 

   150     /**

   151      * EmptyBufferL

   152      * Queues received frame in JB.

   153      * @since Series 60 5.0

   154      * @param CMMFBuffer* - buffer to be queued in the JB

   155      * @return TInt

   156      */

   157     IMPORT_C TInt EmptyBuffer(CMMFBuffer* aBuffer);

   158 

   159 private:

   160 

   161     /**

   162      * C++ default constructor.

   163      */

   164     CVoIPJitterBuffer(MJitterBufferObserver* aObserver);

   165 

   166     /**

   167      * Symbian 2nd phase constructor.

   168      */

   169     void ConstructL();

   170 

   171     /**

   172      * from CActive

   173      */

   174     void DoCancel();

   175 

   176     /**

   177      * from CActive

   178      */

   179     void RunL();

   180 

   181     /**

   182      * from CActive

   183      */

   184     TInt RunError(TInt aError);

   185 

   186 private:

   187     // Internal helper methods

   188 

   189     /**

   190      * Play current frame from JB.

   191      * @since Series 60 5.0

   192      * @param none

   193      * @return void

   194      */

   195     void PlayBuffer();

   196 

   197     /**

   198      * TransitionState

   199      * @since Series 60 5.0

   200      * @param TJBTransitionState

   201      * @param TUint32

   202      * @return void

   203      */

   204     void TransitionState(TJBTransitionState aTransitionState,

   205             TUint32 aStateChangeDelay = 0);

   206 

   207     /**

   208      * Calculates the time interval at which data rate should be slowed down

   209      * when subsequent EmptyBufferL calls are coming too fast.

   210      * @since Series 60 5.0

   211      * @param none

   212      * @return Suggested delay in microseconds.

   213      */

   214     TUint32 DetermineEmptyBufferDelay();

   215 

   216 private:

   217     // Data

   218 

   219     // Jitter buffer Implementation

   220     CVoIPJitterBufferImpl* iJitterBufferImpl;

   221 

   222     // Pointer to databuffer

   223     CMMFBuffer* iPlayBuffer;

   224 

   225     // Jitterbuffer state

   226     TJBState iState;

   227 

   228     // JB Transition State

   229     TJBTransitionState iTransitionState;

   230 

   231     MJitterBufferObserver* iObserver;

   232     TFourCC iCodec;

   233 

   234     RTimer iTimer;

   235     TTime iTmCurrentEmptyBuffer;

   236     TTime iTmPreviousEmptyBuffer;

   237 

   238     TUint32 iSampleInterval;

   239     TUint32 iEmptyBufferDelayThreshold;

   240 

   241     // Current request size of the buffer

   242     TInt iRequestSize;

   243 

   244     };

   245 

   246 #endif  //__VOIPJITTERBUFFER_H

   247 

   248 // End of file