MF_PD_PLAYBACK_ELEMENT_ID attribute

Contains the identifier of the playlist element in the presentation.

Data type

UINT32

Get/set

To get this attribute, call IMFAttributes::GetUINT32.

To set this attribute, call IMFAttributes::SetUINT32.

Applies to

IMFPresentationDescriptor

Remarks

Media sources that deliver playlists can optionally set this attribute on their presentation descriptors.

When a media source delivers a playlist, it sends a MENewPresentation event for each playlist element after the first. This event contains a presentation descriptor for the new playlist element. The media source can assign identifiers to the elements by setting the MF_PD_PLAYBACK_ELEMENT_ID attribute on each presentation descriptor, including the one created by IMFMediaSource::CreatePresentationDescriptor.

A media source might also send the MENewPresentation event because of a dynamic stream switch or a change in the number of streams. In that situation, the value of MF_PD_PLAYBACK_ELEMENT_ID should remain the same across both presentations, to indicate that both presentations represent the same playlist element. If two consecutive presentations have the same value for this attribute, the Microsoft Media Foundation pipeline expects the time stamps to remain continuous across the transition. Therefore, the media source must not use the MF_EVENT_SOURCE_ACTUAL_START attribute when it transitions to the next presentation.

Media sources that implement IMFMediaSourceTopologyProvider should use the MF_TOPONODE_SEQUENCE_ELEMENTID attribute rather than the MF_PD_PLAYBACK_ELEMENT_ID attribute.

The GUID constant for this attribute is exported from mfuuid.lib.

Requirements

See also

Alphabetical List of Media Foundation Attributes

Presentation Descriptor Attributes