IMediaSample Interface

Microsoft DirectShow 9.0

IMediaSample Interface

The IMediaSample interface sets and retrieves properties on media samples. A media sample is a COM object that contains a block of media data. Media samples support the use of shared memory buffers among filters.

Typically, applications do not call methods on this interface. Filters use this interface to set properties on samples, and deliver the samples to a downstream filter. The downstream filter uses the interface to retrieve the properties and read the data. The filter can modify the data in place, or it can copy the sample, modify the copy, and pass the copy downstream.

The IMediaSample2 interface inherits this interface.

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

Method	Description
GetActualDataLength	Retrieves the length of the valid data in the buffer.
GetMediaTime	Retrieves the media times for this sample.
GetMediaType	Retrieves the media type, if the media type differs from the previous sample.
GetPointer	Retrieves a read/write pointer to this buffer's memory.
GetSize	Retrieves the size of the buffer.
GetTime	Retrieves the stream times at which this sample should begin and finish.
IsDiscontinuity	Determines if this sample represents a break in the data stream.
IsPreroll	Determines if this sample is a preroll sample.
IsSyncPoint	Determines if the beginning of this sample is a synchronization point.
SetActualDataLength	Sets the length of the valid data in the buffer.
SetDiscontinuity	Specifies whether this sample represents a break in the data stream.
SetMediaTime	Sets the media times for this sample.
SetMediaType	Sets the media type for the sample.
SetPreroll	Specifies whether this sample is a preroll sample.
SetSyncPoint	Specifies whether the beginning of this sample is a synchronization point.
SetTime	Sets the stream time when this sample should begin and finish.

Requirements

Header: Declared in Strmif.h; include Dshow.h.

Library: Use Strmiids.lib.