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CMMFSwCodecWrapper Class Reference

class CMMFSwCodecWrapper : public CMMFHwDevice

Class to make a CMMFSwCodec into a CMMFHwDevice ECOM plugin.

Most of the code to make a CMMFSwCodec into a CMMFHwDevice ECOM plugin is provided in CMMFSwCodecWrapper. Someone writing a plugin derrived from CMMFSwCodecWrapper only needs to provide the standard ECOM implementation code, constructors and destructors and implement the Codec() function which should return the appropriate CMMFSwCodec.

Third parties using CMMFSwCodecWrapper that do not use the RMdaDevSound API to talk to the sound drivers would need to port the datapaths for their own sound drivers. Third parties would also need to change the custom interfaces where necessary.

Inherits from

CMMFSwCodecWrapper
- CMMFHwDevice
  - CBase

Public Member Functions
	~CMMFSwCodecWrapper()

Protected Member Functions
	CMMFSwCodecWrapper()
CMMFSwCodec &	Codec()
IMPORT_C TAny *	CustomInterface(TUid)
IMPORT_C TInt	DeleteCodec()
IMPORT_C TInt	Init(THwDeviceInitParams &)
IMPORT_C TInt	Pause()
IMPORT_C TInt	SetConfig(TTaskConfig &)
IMPORT_C void	SetVbrFlag()
IMPORT_C TInt	Start(TDeviceFunc, TDeviceFlow)
IMPORT_C TInt	Stop()
IMPORT_C TInt	StopAndDeleteCodec()
IMPORT_C TInt	ThisHwBufferEmptied(CMMFBuffer &)
IMPORT_C TInt	ThisHwBufferFilled(CMMFBuffer &)

Private Member Functions
TInt	StartConvert()
TInt	StartDecode()
TInt	StartEncode()

Inherited Functions
	CBase::CBase()
	CBase::Delete(CBase *)
	CBase::Extension_(TUint,TAny &,TAny )
	CBase::operator new(TUint)
	CBase::operator new(TUint,TAny *)
	CBase::operator new(TUint,TLeave)
	CBase::operator new(TUint,TLeave,TUint)
	CBase::operator new(TUint,TUint)
	CBase::~CBase()
	CMMFHwDevice::NewL(TFileName)
	CMMFHwDevice::NewL(TUid)
	CMMFHwDevice::NewL(const TFourCC &,const TFourCC &)
	CMMFHwDevice::NewL(const TFourCC &,const TFourCC &,const TDesC &)
	CMMFHwDevice::~CMMFHwDevice()

Protected Attributes
TInt	iChannels
CMMFSwCodec *	iCodec
CMMFSwCodecDataPath *	iDataPath
TUint	iDeviceBufferSize
MPlayCustomInterface *	iPlayCustomInterface
MRecordCustomInterface *	iRecordCustomInterface
TInt	iSampleRate
CMMFDataBuffer *	iSinkBuffer
CMMFDataBuffer *	iSourceBuffer

Inherited Attributes
	CMMFHwDevice::iHwDeviceObserver

Constructor & Destructor Documentation

CMMFSwCodecWrapper()

IMPORT_C

CMMFSwCodecWrapper

(

)

[protected]

Constructor.

~CMMFSwCodecWrapper()

IMPORT_C

~CMMFSwCodecWrapper

(

)

[virtual]

Destructor.

The destructor is called by ECom framework allowing derived classes to clean up implementation specific resources. The sound device drivers are freed.

Member Functions Documentation

Codec()

CMMFSwCodec &

Codec

(

)

[protected, pure virtual]

This method must return the CMMFSwCodec used by the derived CMMFSwCodecWrapper class. The method should create the CMMFSwCodec if it hasn't done so already.

This is a virtual function that each derived class must implement.

CustomInterface(TUid)

IMPORT_C TAny *

CustomInterface

(

TUid

aInterfaceId

)

[protected, virtual]

Retrieves a custom interface to the device. The reference CMMFSwCodecWrapper supports two standard custom interfaces, MPlayCustomInterface and MRecordCustomInterface.

Parameters

TUid aInterfaceId

Interface UID, defined with the custom interface. aInterface = KMmfPlaySettingsCustomInterface for MPlayCustomInterface, aInterface = KMmfRecordSettingsCustomInterface for MRecordCustomInterface. aInterface = KMmfUidEmptyBuffersCustomInterface for MEmptyBuffersCustomInterface Actual device implementations of CMMFSwCodecWrapper may do this differently however.

DeleteCodec()

IMPORT_C TInt

DeleteCodec

(

)

[protected, virtual]

Deletes the codec This default implementation does nothing but real hardware devices might use this method to free up resources.

Init(THwDeviceInitParams &)

IMPORT_C TInt

Init

(

THwDeviceInitParams &

aDevInfo

)

[protected, virtual]

Initializes the hardware device tasks - in the case of a sw codec wrapper 'hardware device' this consits of loading the sound device drivers and creating the CMMFSwCodec.

Parameters

THwDeviceInitParams & aDevInfo

Device initialization parameters. Only the iHwDeviceObserver is used for CMFSwCodecWrapper derived CMMFHwDevices.

Pause()

IMPORT_C TInt

Pause

(

)

[protected, virtual]

Temporarily suspends the current task of decoding or encoding.

SetConfig(TTaskConfig &)

IMPORT_C TInt

SetConfig

(

TTaskConfig &

aConfig

)

[protected, virtual]

Used to configure the sample rate and stereo mode of a CMMFHwDevice plugin.

The configuration of HwDevices is device specific and is not used in any of the reference devices that return KErrNotSupported.

Parameters

TTaskConfig & aConfig

The device configuration.

SetVbrFlag()

IMPORT_C void

SetVbrFlag

(

)

[protected]

Used to set iVbrFlag on the datapath.

This method is used to set the iVbrFlag in datapath. This flag is added to datapath to avail the alternative dataflow wherein datapath makes sure that destinationbuffer is filled to its maximum length before sending it to the sound driver. Sending the buffer directly to the device causes underflow incase of VBR codecs.

Start(TDeviceFunc, TDeviceFlow)

IMPORT_C TInt	Start	(	TDeviceFunc	aFuncCmd,
			TDeviceFlow	aFlowCmd
		)	[protected, virtual]

Starts Encoding or Decoding task(s) based on the parameter specified.

Parameters

TDeviceFunc aFuncCmd	The device function specifying the requested service i.e. decode or encode where EDevEncode = Record, EDevDecode = Play and EDevNullFunc = Convert.
TDeviceFlow aFlowCmd	The device flow directions for requested service. This parameter is ignored for CMMFSwCodecWrapper CMMFHwDevicePlugins

StartConvert()

TInt

StartConvert

(

)

[private]

StartDecode()

TInt

StartDecode

(

)

[private]

StartEncode()

TInt

StartEncode

(

)

[private]

Stop()

IMPORT_C TInt

Stop

(

)

[protected, virtual]

Stops the current on-going task.

StopAndDeleteCodec()

IMPORT_C TInt

StopAndDeleteCodec

(

)

[protected, virtual]

Stops and deletes the codec.

This default implementation simply calls DeleteCodec() and then Stop() but real hardware devices might use this method to free up resources.

ThisHwBufferEmptied(CMMFBuffer &)

IMPORT_C TInt

ThisHwBufferEmptied

(

CMMFBuffer &

aBuffer

)

[protected, virtual]

Call this function to notify hardware device implementation that data in aEmptyBufferPtr from encoding is processed.

Parameters

CMMFBuffer & aBuffer

The data buffer processed by observer.

ThisHwBufferFilled(CMMFBuffer &)

IMPORT_C TInt

ThisHwBufferFilled

(

CMMFBuffer &

aFillBufferPtr

)

[protected, virtual]

Call this function to notify hardware device implementation that data is available in aFillBufferPtr for decoding.

Parameters

CMMFBuffer & aFillBufferPtr

The data buffer filled by the observer.

Member Data Documentation

TInt iChannels

TInt

iChannels

[protected]

The number of channels of the sound device

CMMFSwCodec * iCodec

CMMFSwCodec *

iCodec

[protected]

The software codec used

CMMFSwCodecDataPath * iDataPath

CMMFSwCodecDataPath *

iDataPath

[protected]

The datapath used to transfer the data

TUint iDeviceBufferSize

TUint

iDeviceBufferSize

[protected]

The buffer size of the sound device

MPlayCustomInterface * iPlayCustomInterface

MPlayCustomInterface *

iPlayCustomInterface

[protected]

The play custom interface

MRecordCustomInterface * iRecordCustomInterface

MRecordCustomInterface *

iRecordCustomInterface

[protected]

The record custom interface

TInt iSampleRate

TInt

iSampleRate

[protected]

The sample rate of the sound device

CMMFDataBuffer * iSinkBuffer

CMMFDataBuffer *

iSinkBuffer

[protected]

The sink buffer for the codec

CMMFDataBuffer * iSourceBuffer

CMMFDataBuffer *

iSourceBuffer

[protected]

The source buffer for the codec