SetMediaType method sets the media type for the connection.
Pointer to a CMediaType object that specifies the media type.
This method establishes the format for a pin connection. Before calling this method, the pin calls the CBasePin::CheckMediaType method to determine whether the media type is acceptable. Therefore, the pmt parameter is assumed to be an acceptable media type.
In the base class, this method sets the CBasePin::m_mt member variable and returns S_OK. A derived class can override this method if it requires notification when the media type is set.