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IDirectMusicBuffer8 Interface

The IDirectMusicBuffer8 interface represents a buffer containing time-stamped data (typically in the form of MIDI messages) being sequenced to a port. The buffer contains a small amount of data, typically less than 200 milliseconds. Unless your application is doing its own sequencing, you do not need to use the methods of this interface.

IDirectMusicBuffer8 is a type definition for IDirectMusicBuffer. The two interface names are interchangeable.

Buffer objects are completely independent of port objects until the buffer is passed to the port by a call to the IDirectMusicPort8::PlayBuffer or the IDirectMusicPort8::Read method. The application is then free to reuse the buffer.

In addition to the methods inherited from IUnknown, the IDirectMusicBuffer8 interface exposes the following methods.

Method Description
Flush Discards all data in the buffer.
GetBufferFormat Retrieves the GUID that represents the buffer format.
GetMaxBytes Retrieves the number of bytes that can be stored in the buffer.
GetNextEvent Returns information about the next message in the buffer and advances the read pointer.
GetRawBufferPtr Returns a pointer to the underlying buffer data structure.
GetStartTime Retrieves the start time of the data in the buffer, relative to the master clock.
GetUsedBytes Retrieves the number of bytes of data in the buffer.
PackStructured Inserts fixed-length data (typically a MIDI channel message), along with timing and routing information, into the buffer.
PackUnstructured Inserts unstructured data (typically a MIDI system-exclusive message), along with timing and routing information, into the buffer
ResetReadPtr Sets the read pointer to the start of the data in the buffer.
SetStartTime Sets the start time of the data in the buffer, relative to the master clock.
SetUsedBytes Sets the number of bytes of data in the buffer.
TotalTime Returns the total time spanned by the data in the buffer.

The LPDIRECTMUSICBUFFER8 type is defined as a pointer to the IDirectMusicBuffer8 interface:

  typedef IDirectMusicBuffer8 *LPDIRECTMUSICBUFFER8;

Requirements

**  Minimum Supported Client:** Windows 2000.
**  Minimum Supported Server:** Windows 2000 Server.

**  Header:** Dmusicc.h

See Also

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