Stores the time (in 100-nanoseconds units) at which the presentation must begin, relative to the start of the media source.
To get this attribute, call IMFAttributes::GetUINT64.
To set this attribute, call IMFAttributes::SetUINT64.
The MF_PD_PLAYBACK_BOUNDARY_TIME attribute is optional for media sources in a playlist. This value indicates the actual start time of the presentation. Consider a playlist that includes media sources Element1, Element2, and Element3 in a sequence. 15 seconds after Element1 starts playing, a dynamic stream change occurs. The new stream must start playing 15 seconds into the presentation. However, the keyframe nearest the presentation time of 15 seconds is at 12 seconds for the new stream. To start the new presentation at 15 seconds, a markin is required so that the decoded samples are dropped from 12 seconds to 15 seconds.
Before the transition, the MENewPresentation event is raised by the media source. This returns the presentation descriptor that contains the MF_PD_PLAYBACK_ELEMENT_ID attribute for Element1. Additionally, it contains the MF_PD_PLAYBACK_BOUNDARY_TIME attribute that is set to 15 seconds to indicate the time when the transition occurred. The media source performs the markin at 15 seconds after decoding, which prevents the frames from 12 seconds to 15 seconds from being displayed.
This value affects only markin time and does not affect how the Media Session adjusts time stamps. This attribute is ignored unless the media source indicates through the MF_PD_PLAYBACK_ELEMENT_ID attribute that this presentation is the same playback element as the previous one.
The MF_PD_PLAYBACK_BOUNDARY_TIME attribute is similar to the MF_TOPONODE_MEDIASTART attribute that is set on the topology node. For applications running on Windows Vista, media sources that implement IMFMediaSourceTopologyProvider should use MF_TOPONODE_MEDIASTART instead of MF_PD_PLAYBACK_BOUNDARY_TIME.
The GUID constant for this attribute is exported from mfuuid.lib.
Minimum supported client
|Windows 7 [desktop apps | Windows Store apps]|
Minimum supported server
|Windows Server 2008 R2 [desktop apps | Windows Store apps]|