This buffer is bigger than the ASIO buffers, to allow compensation of any delays during reading and writing of data to disk. In general there can be two modes of operation: 

• The recorded data is processed in real time and immedately played back.

The extended buffer is not used in this case.

• When the source of data is subject to larger IO delays when coming or going to

other sources like disk drive, a secondary extended size buffer is neccessary to avoid skipping. Typical size of this buffer is between 250ms and 1000ms. 

The ASIO buffers are processed within the drivers thread, but extended buffer is processed in the main application thread and OnExtendedBufferRead, OnInputBufferReady events are triggered via windows messages. 

This value can not be less than ActualLatency and will be modified if needed to be at least 2*ActualLatency when the processing starts.

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