DASH - Understanding MPD at availabilityStartTime

[Thiago Santos]

Hello,

I've been re-reading DASH spec to clear up some parts, specially 
availabilityStartTime.

 From the spec:

For @type='dynamic' this attribute shall be present. In
this case it specifies the anchor for the computation of
the earliest availability time (in UTC) for any Segment in
the Media Presentation.

What happens when you have a SegmentList, in which the old segments are 
removed from the list and new ones are added. Should 
availabilityStartTime be updated to 'point' to the availability of the 
updated MPD's earliest segment or should it keep referring to the first 
ever available segment that was already removed?

At the moment we are implementing the 2nd alternative in dashdemux but I 
found 1 stream that doesn't work with this. (Unless you are willing to 
wait 16 thousand days for it to start playing).

Any inputs from people working with DASH or links to live DASH streams 
will be of great help.

Regards,

-- 
Thiago Sousa Santos
Senior Multimedia Engineer, Open Source Group
Samsung Research America - Silicon Valley