Class CMMFSwCodecWrapper

class CMMFSwCodecWrapper : public CMMFHwDevice;

Description

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 CMMFSwCodecWrapper::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.

Derivation

• CMMFHwDevice - No description.

• CMMFSwCodecWrapper - Class to make a CMMFSwCodec into a CMMFHwDevice ECOM plugin.

Members

Defined in CMMFSwCodecWrapper:

• CMMFSwCodecWrapper()Constructor.
• Codec()This method must return the CMMFSwCodec used by the derived CMMFSwCodecWrapper c...
• CustomInterface(TUid)Retrieves a custom interface to the device. The reference CMMFSwCodecWrapper sup...
• DeleteCodec()Deletes the codec This default implementation does nothing but real hardware dev...
• Init(THwDeviceInitParams &)Initializes the hardware device tasks - in the case of a sw codec wrapper 'hardw...
• Pause()Temporarily suspends the current task of decoding or encoding.
• SetConfig(TTaskConfig &)Used to configure the sample rate and stereo mode of a CMMFHwDevice plugin.
• SetVbrFlag()Used to set iVbrFlag on the datapath.
• Start(TDeviceFunc,TDeviceFlow)Starts Encoding or Decoding task(s) based on the parameter specified.
• Stop()Stops the current on-going task.
• StopAndDeleteCodec()Stops and deletes the codec.
• ThisHwBufferEmptied(CMMFBuffer &)Call this function to notify hardware device implementation that data in aEmptyB...
• ThisHwBufferFilled(CMMFBuffer &)Call this function to notify hardware device implementation that data is availab...
• iChannelsThe number of channels of the sound device
• iCodecThe software codec used
• iDataPathThe datapath used to transfer the data
• iDeviceBufferSizeThe buffer size of the sound device
• iPlayCustomInterfaceThe play custom interface
• iRecordCustomInterfaceThe record custom interface
• iSampleRateThe sample rate of the sound device
• iSinkBufferThe sink buffer for the codec
• iSourceBufferThe source buffer for the codec
• ~CMMFSwCodecWrapper()Destructor.

IMPORT_C virtual ~CMMFSwCodecWrapper();

Description

Destructor.

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

protected: IMPORT_C CMMFSwCodecWrapper();

Description

Constructor.

protected: IMPORT_C virtual TInt Init(THwDeviceInitParams &aDevInfo);

Description

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

Return value

protected: IMPORT_C virtual TInt Start(TDeviceFunc aFuncCmd, TDeviceFlow aFlowCmd);

Description

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

Parameters

Return value

protected: IMPORT_C virtual TInt Stop();

Description

Stops the current on-going task.

Return value

protected: IMPORT_C virtual TInt Pause();

Description

Temporarily suspends the current task of decoding or encoding.

Return value

protected: IMPORT_C virtual TAny* CustomInterface(TUid aInterfaceId);

Description

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

Parameters

Return value

protected: IMPORT_C virtual TInt ThisHwBufferFilled(CMMFBuffer &aFillBufferPtr);

Description

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

Parameters

Return value

protected: IMPORT_C virtual TInt ThisHwBufferEmptied(CMMFBuffer &aBuffer);

Description

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

Parameters

Return value

protected: IMPORT_C virtual TInt SetConfig(TTaskConfig &aConfig);

Description

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

Return value

protected: IMPORT_C virtual TInt StopAndDeleteCodec();

Description

Stops and deletes the codec.

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

Return value

protected: IMPORT_C virtual TInt DeleteCodec();

Description

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

Return value

protected: virtual CMMFSwCodec& Codec()=0;

Description

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.

Return value

protected: IMPORT_C void SetVbrFlag();

Description

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.

protected: CMMFSwCodec * iCodec;

Description

The software codec used

protected: CMMFDataBuffer * iSourceBuffer;

Description

The source buffer for the codec

protected: CMMFDataBuffer * iSinkBuffer;

Description

The sink buffer for the codec

protected: CMMFSwCodecDataPath * iDataPath;

Description

The datapath used to transfer the data

protected: MPlayCustomInterface * iPlayCustomInterface;

Description

The play custom interface

protected: MRecordCustomInterface * iRecordCustomInterface;

Description

The record custom interface

protected: TUint iDeviceBufferSize;

Description

The buffer size of the sound device

protected: TInt iSampleRate;

Description

The sample rate of the sound device

protected: TInt iChannels;

Description

The number of channels of the sound device