Microsoft DirectX 8.0

DMO_MEDIA_TYPE Structure

Structures

Describes the format of the data used by a stream in a Microsoft® DirectX® Media Object (DMO).

Note  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
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 TypeFormat Structure
FORMAT_NoneNo format type
FORMAT_MPEGVideoMPEG1VIDEOINFO
FORMAT_MPEG2Video MPEG2VIDEOINFO
FORMAT_VideoInfoVIDEOINFOHEADER
FORMAT_VideoInfo2 VIDEOINFOHEADER2
FORMAT_WaveFormatExWAVEFORMATEX
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.