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The CBasicAudioclass handles the IDispatchinterface component of the IBasicAudiointerface and leaves the properties and methods of IBasicAudiopure virtual to be implemented by a derived filter class.
The CBasicAudio::GetIDsOfNames, CBasicAudio::GetTypeInfo, CBasicAudio::GetTypeInfoCount, and CBasicAudio::Invokemember functions are standard implementations of the IDispatchinterface using the CBaseDispatchclass (and a type library) to parse the commands and pass them to the pure virtual IBasicAudiomethods.
Microsoft DirectShow uses units of 100th of a decibel for the volume scale. A value of 0 indicates maximum volume supported by the device. A value of –10,000 is the minimum volume (normally silence). Balance is expressed in the range –10,000 to 10,000, with 0 being neutral. A negative balance value means that the right channel is attenuated by this dB value (that is, it is quieter). Similarly, a positive balance value means that the right channel is louder than the left; that is, the left channel is attenuated by the corresponding negative decibel value.
Member Functions
| CBasicAudio | Constructs a CBasicAudioobject. |
Implemented INonDelegatingUnknown Methods
| NonDelegatingQueryInterface | Retrieves a specified reference-counted interface. |
Implemented IDispatch Methods
| GetIDsOfNames | Maps a single member and an optional set of parameters to a corresponding set of integer dispatch identifiers, which can be used during subsequent calls to the CBasicAudio::Invokemember function. |
| GetTypeInfo | Retrieves a type-information object, which can retrieve the type information for an interface. |
| GetTypeInfoCount | Retrieves the number of type-information interfaces provided by an object. |
| Invoke | Provides access to properties and methods exposed by an object. |