MF_PD_ASF_MARKER attribute

Specifies the markers in an Advanced Systems Format (ASF) file. This attribute corresponds to the Marker Object in the ASF header, defined in the ASF specification.

Data type

Byte array


This attribute applies to presentation descriptors for ASF content.

The IMFASFContentInfo::GeneratePresentationDescriptor method creates the presentation descriptor and generates this attribute from the Marker Object. The following table shows the format of the blob:

Marker Object fieldData typeSizeDescription
Markers CountDWORD4 bytesNumber of markers
MarkersBYTE[]VariesArray of markers


The first DWORD is the number of markers, followed by an array of markers. Each marker has the following format:

Marker Object fieldData typeSizeDescription
Marker Description LengthDWORD4 bytesSize of the description string, in bytes, including the NULL character.
Marker DescriptionWCHAR[]VariesNull-terminated string that describes the marker.
Presentation TimeLONGLONG8 bytesPresentation time of the marker, in 100-nanosecond units.
Send TimeLONGLONG8 bytesSend time of the marker entry, in milliseconds.
OffsetUINT648 bytesOffset, in bytes, into the Data Object that specifies the position of the market.



Minimum supported client

Windows Vista [desktop apps only]

Minimum supported server

Windows Server 2008 [desktop apps only]



See also

Alphabetical List of Media Foundation Attributes
Presentation Descriptor Attributes
ASF Header Object
Presentation Descriptors