Custom interface class for play functionality created by the CMMFSwCodecWrapper::CustomInterface() method. It provides access to miscellaneous functionality such as volume settings. Ports of the sw codec wrapper may do this differently eg. via EAP. Note Users should not use RMdaDevSound::TCurrentSoundFormatBuf to send across the sample rate and channels because 1) it would mean mmfswcodecwrapper.h would have to include mdasound.h 2) the buffer size and encoding members are not required and 3) 3rd party ports may not use RMdaDevSound.

Note also that this interface is just a simple interface to get and set values. No checking is performed on the values sent (hence the Set methods do not return an error code).