DMO_MEDIA_TYPE

A version of this page is also available for

Windows Embedded CE 6.0 R3

4/8/2010

This structure describes the format of the data used by a stream in a DirectX DMO. This structure is identical to the Microsoft DirectShow AM_MEDIA_TYPE structure.

Syntax

typedef struct _DMOMediaType {
  GUID majortype;
  GUID subtype;
  BOOL bFixedSizeSamples;
  BOOL bTemporalCompression;
  ULONG lSampleSize;
  GUID formattype;
  IUnknown* pUnk;
  ULONG cbFormat;
  [size_is(cbFormat)] BYTE* pbFormat;
 } DMO_MEDIA_TYPE;

Members

• majortype
  A GUID identifying the stream's major media type. This must be one of the DMO Media Types.

• subtype
  Subtype GUID of the stream.

• bFixedSizeSamples
  If TRUE, samples are of a fixed size. This field is informational only. For audio, it is generally set to TRUE. For video, it is usually TRUE for uncompressed video and FALSE for compressed video.

• bTemporalCompression
  If TRUE, samples are compressed using temporal (interframe) compression. A value of TRUE indicates that not all frames are key frames. This field is informational only.

• lSampleSize
  Size of the sample, in bytes. For compressed data, the value can be zero.

• formattype
  GUID specifying the format type. The pbFormat member points to the corresponding format structure. Format types include the following.

  Format type	Format structure
  FORMAT_None	No format type
  FORMAT_MPEGVideo	MPEG1VIDEOINFO
  FORMAT_MPEG2Video	MPEG2VIDEOINFO
  FORMAT_VideoInfo	VIDEOINFOHEADER
  FORMAT_VideoInfo2	VIDEOINFOHEADER2
  FORMAT_WaveFormatEx	WAVEFORMATEX

• pUnk
  Not used.

• cbFormat
  Size of the format block of the media type.

• pbFormat
  Pointer to the format structure. The structure type is specified by the formattype member. The format structure must be present, unless formattype is GUID_NULL or FORMAT_None.

Remarks

The bFixedSizeSamples, bTemporalCompression, and lSampleSize members are for compatibility with DirectShow. Other DMO clients are not required to use them.

Requirements

See Also

Reference

DMO Structures
AM_MEDIA_TYPE
MPEG1VIDEOINFO
MPEG2VIDEOINFO
VIDEOINFOHEADER
VIDEOINFOHEADER2
Media Types and Sub Types

Other Resources

WAVEFORMATEX (Waveform Audio)