MPEG-DASH(MPD@type='dynamic)/MPD@availabilityStartTime

Wowza Streaming Engine
1

According to the standard MPD@availabilityStartTime should not be updated between MPD updates

8.4.2

Media Presentation Description constraints

  • When the MPD is updated, the value of MPD@availabilityStartTime shall be the same in the

original and the updated MPD

But wowza update MPD@availabilityStartTime after every segment goes out of SegmentTimeline for sergment duration value.

But according to following requirements this increase segment availability start time more and more from it’s valid value as both MDP segment start time grow and availabilityStartTime grows as well.

5.3.9.5.3

Media Segment information

For services with MPD@type=‘dynamic’, the Segment availability start time of a Media Segment is the sum

of

 the value of the MPD@availabilityStartTime,

 the PeriodStart time of the containing Period as defined in 5.3.2.1,

 the MPD start time of the Media Segment, and

 the MPD duration of the Media Segment.

This makes segment availability start time invalid after short period of time after live session start

2

Hi,

The availabilityStartTime requirement is actually new in Version 2 of the DASH spec, which we do not support as of yet.

Our initial implementation worked with the previous versions of the players we had available.

We are planning to update our DASH implementation based on the latest spec and latest dash.js player.

Not sure when that will be though, but it is coming.

Daren

3

Hi

There isn’t a update for this yet. No time line at the moment.

Daren

4

Daren,

thanks a lot ! It makes sense now.

5

Daren,

Is there an updated timeline on when this issue might be fixed?

Thanks,

–Thomas

6

Daren,

Thanks for getting back to me. Is there a version of Dash.js known to work with the latest Wowza Streaming Engine?

Thanks,

–Thomas