KSDATAFORMAT structure

The KSDATAFORMAT structure is a variable-length structure that describes a data format.

Syntax

typedef struct {
  ULONG FormatSize;
  ULONG Flags;
  ULONG SampleSize;
  ULONG Reserved;
  GUID  MajorFormat;
  GUID  SubFormat;
  GUID  Specifier;
} KSDATAFORMAT, *PKSDATAFORMAT, KSDATARANGE, *PKSDATARANGE;

Members

FormatSize

Specifies the size, in bytes, of the KSDATAFORMAT structure. This must be at least sizeof(KSDATAFORMAT), but can be larger for specific settings of MajorFormat, SubFormat, and Specifier. See the descriptions for these members for more information.

Flags

Must be zero.

SampleSize

Specifies the sample size of the data, for fixed sample sizes, or zero, if the format has a variable sample size.

Reserved

Reserved for system use. Drivers must set this member to zero.

MajorFormat

Specifies the general format type. The data formats that are currently supported can be found in the KSDATAFORMAT_TYPE_XXX symbolic constants in the ksmedia.h header file that is included in the Windows Driver Kit (WDK). A data stream that has no particular format should use KSDATAFORMAT_TYPE_STREAM (defined in ks.h) as the value for its MajorFormat. For more information about this member, see Remarks.

SubFormat

Specifies the subformat of a general format type. The data subformats that are currently supported can be found in the KSDATAFORMAT_SUBTYPE_XXX symbolic constants in the ksmedia.h header file that is included in the WDK. Major formats that do not support subformats should use the KSDATAFORMAT_SUBTYPE_NONE value for this member. For more information about this member, see Remarks.

Specifier

Specifies additional data format type information for a specific setting of MajorFormat and SubFormat. The significance of this field is determined by the major format (and subformat, if the major format supports subformats). For example, Specifier can represent a particular encoding of a subformat, or it can be used to specify what type of data structure follows KSDATAFORMAT in memory.

The following specifiers (defined in ks.h) are of general use:

KSDATAFORMAT_SPECIFIER_NONE

Stands for no specifier. Used for formats that do not support specifiers.

KSDATAFORMAT_SPECIFIER_FILENAME

Indicates that a null-terminated Unicode string immediately follows the KSDATAFORMAT structure in memory.

KSDATAFORMAT_SPECIFIER_FILEHANDLE

Indicates that a file handle immediately follows KSDATAFORMAT in memory.

Remarks

At the minimum, a data format is specified by the MajorFormat, the SubFormat, and the Specifier members. A family of similar data formats can share the same values for MajorFormat, SubFormat, and Specifier. In that case, the specific data format is distinguished by additional data that follows the Specifier member in memory.

For a list of MajorFormat, SubFormat, and Specifier combinations, see Stream Categories and its subtopics.

Requirements

See also

Stream Categories

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Build date: 10/26/2012