DMO_MEDIA_TYPE Structure
The DMO_MEDIA_TYPE structure describes the format of the data used by a stream in a Microsoft DirectX Media Object (DMO).
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
Major type GUID of the stream.
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_DVInfo | DVINFO |
| FORMAT_MPEG2Video | MPEG2VIDEOINFO |
| FORMAT_MPEGVideo | MPEG1VIDEOINFO |
| FORMAT_None | NULL |
| 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
This structure is identical to the DirectShow AM_MEDIA_TYPE structure. The bFixedSizeSamples, bTemporalCompression, and lSampleSize members are for compatibility with DirectShow. Other DMO clients are not required to use them.
Requirements
Header: Mediaobj.h
See Also