1 // Copyright (c) 2002-2009 Nokia Corporation and/or its subsidiary(-ies).

     2 // All rights reserved.

     3 // This component and the accompanying materials are made available

     4 // under the terms of "Eclipse Public License v1.0"

     5 // which accompanies this distribution, and is available

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

     7 //

     8 // Initial Contributors:

     9 // Nokia Corporation - initial contribution.

    10 //

    11 // Contributors:

    12 //

    13 // Description:

    14 // include\mmf\utils\rateconvert.h

    15 // 

    16 //

    17 

    18 #ifndef RATECONVERT_H

    19 #define RATECONVERT_H

    20 

    21 /**

    22 @internalTechnology

    23 @file

    24 */

    25 

    26 #include <e32base.h>

    27 

    28 /**

    29 Base utility class to change the sample rate of audio data in a buffer

    30 */

    31 class CChannelAndSampleRateConverter : public CBase

    32 	{

    33 protected:

    34 	CChannelAndSampleRateConverter();

    35 	

    36 public:

    37 	/*

    38 	Create a converter that will do rate and channel conversion as requested

    39 	*/

    40 	IMPORT_C static CChannelAndSampleRateConverter* CreateL(TInt aFromRate,TInt aFromChannels,

    41 												 TInt aToRate,TInt aToChannels);

    42 	/**

    43 	Reads the audio data from the source buffer,

    44 	converts the number of channels and the sample rate

    45 	and copies the result to the destination buffer

    46 

    47 	@param  aSrcBuffer

    48 	        The source buffer containing the audio data to convert.

    49 	@param  aDstBuffer

    50 	        The destination buffer - assumed big enough

    51 

    52 	@return The length of the source buffer that was consumed.

    53 	*/

    54 	virtual TInt Convert(const TDesC8& aSrcBuffer, TDes8& aDstBuffer)=0;

    55 	virtual void Reset()=0;

    56 

    57 	/*

    58 	Indicates what buffer size is required to hold the converted data.

    59 	Support size of original buffer. 

    60 	aRoundUpToPower means give next power of 2 size up from raw size.

    61 	NB. May be bigger than strictly necessary.

    62 	*/

    63 	virtual TInt MaxConvertBufferSize(TInt aSrcBufferSize, TBool aRoundUpToPower=EFalse)=0;

    64 	};

    65 

    66 

    67 #endif

    68