devsound/a3facf/inc/maudiocodec.h
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     1 /*
       
     2 * Copyright (c) 2006-2009 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:
       
    15 *
       
    16 */
       
    17 
       
    18 
       
    19 
       
    20 
       
    21 /**
       
    22  @file
       
    23  @publishedPartner
       
    24  @released
       
    25 */
       
    26 
       
    27 #ifndef MAUDIOCODEC_H
       
    28 #define MAUDIOCODEC_H
       
    29 
       
    30 #include <a3f/a3fbase.h>
       
    31 #include <a3f/maudioprocessingunit.h>
       
    32 #include <a3f/maudiocodecobserver.h>
       
    33 
       
    34 
       
    35 /**
       
    36  * A generic abstract interface for codecs.
       
    37  *
       
    38  * The client must add a codec to a stream for operation.
       
    39  * The codec can only be added to a stream when the codec is in uninitialized state.
       
    40  * The codec can only be removed from a stream when the codec is in uninitialized or dead states.
       
    41  */
       
    42 class MAudioCodec
       
    43 	{
       
    44 	public:
       
    45 	
       
    46 	/**
       
    47 	 * Sets the codec format.
       
    48 	 *
       
    49 	 * For encoders this sets the output format.
       
    50 	 * For decoders this configures the input format.
       
    51 	 * Format must be set before the codec can transfer to initialized state.
       
    52 	 *
       
    53 	 * @param aFormat codec format.
       
    54 	 * @return An error code. KErrNone on success, otherwise one of the system wide error codes.
       
    55 	 */
       
    56 	virtual TInt SetFormat(TUid aFormat)=0;
       
    57 
       
    58 	/**
       
    59 	* Sets the sample rate in samples/sec.
       
    60 	*
       
    61 	* sets the sample rate of the encoded data,
       
    62 	* and says nothing about the sample rate used on the output device
       
    63 	* or whether re-sampling is required that is up to the adaptation.
       
    64 	* the result of the operation is returned by MAudioCodecObserver::SampleRateSet().
       
    65 	*
       
    66 	* @param aSampleRate sample rate to be used, in samples/sec.
       
    67 	* @return An error code. KErrNone on success, otherwise one of the system wide error codes.
       
    68 	*/
       
    69 	virtual TInt SetSampleRate(TInt aSampleRate)=0;
       
    70 
       
    71 	/**
       
    72 	* Sets the mode, e.g. mono/stereo. 
       
    73 	* The result of the operation is returned by MAudioCodecObserver::ModeSet().
       
    74 	*
       
    75 	* @param aMode uid stating the mode.
       
    76 	* @return An error code. KErrNone on success, otherwise one of the system wide error codes.
       
    77 	*/
       
    78 	virtual TInt SetMode(TUid aMode)=0;
       
    79 
       
    80 	/**
       
    81 	* This returns a list of supported sample rates. The list need just include those of the standard list 
       
    82 	* that are supported. Includes rates supported by sample rate conversion. 
       
    83 	* GetSupportedSampleRatesComplete() callback shows result.
       
    84 	* TODO Need to document that the implementation is responsible for calling Reset() on aSupportedRates.
       
    85 	*
       
    86 	* @param aSupportedRates array that is populated with the supported rates list.
       
    87 	* @return An error code. KErrNone on success, otherwise one of the system wide error codes.
       
    88 	*/
       
    89 	virtual TInt GetSupportedSamplesRates(RArray<TInt>& aSupportedRates)=0;
       
    90 
       
    91 	/**
       
    92 	* This returns a list of supported sample modes. The list corresponds to the current configuration 
       
    93 	* and support may include the use of mono/stereo conversion etc. 
       
    94 	* GetSupportedModesComplete() callback shows result.
       
    95 	* TODO Need to document that the implementation is responsible for calling Reset() on aSupportedModes.
       
    96 	*
       
    97 	* @param aSupportedModes array that is populated with the supported modes list.
       
    98 	* @return An error code. KErrNone on success, otherwise one of the system wide error codes.
       
    99 	*/
       
   100 	virtual TInt GetSupportedModes(RArray<TUid>& aSupportedModes)=0;
       
   101 
       
   102 	/**
       
   103 	* Registers an audio codec observer.
       
   104 	*
       
   105 	* Note that this function is meant for clients of the Audio codec. 
       
   106 	* The client should unregister using UnregisterAudioCodecObserver() when applicable
       
   107 	*
       
   108 	* @param aObserver reference to the observer to register.
       
   109 	* @return an error code. KErrNone if successful.
       
   110 	*				KErrAlreadyExists if the client is already registered.
       
   111 	*				KErrOutOfMemory in case of memory exhaustion.
       
   112 	*/
       
   113 	virtual TInt RegisterAudioCodecObserver(MAudioCodecObserver& aObserver)=0;
       
   114 
       
   115 	/**
       
   116 	* Unregisters an audio codec observer.
       
   117 	*
       
   118 	* @param aObserver reference to the observer to unregister.
       
   119 	* @return an error code.  KErrNone if successful.
       
   120 	* 						KErrNotFound if the client has not been registered as observer.
       
   121 	*/
       
   122 	virtual void UnregisterAudioCodecObserver(MAudioCodecObserver& aObserver)=0;
       
   123 
       
   124 	};
       
   125 
       
   126 #endif // MAUDIOCODEC_H