Wowza Community

A/V sync with "elst" track atom

We are using WMS (European Institution) for VOD applications.

For some not (A/V) synchronized file, we are using some tools to

introducing some start delay on ncertain tracks. ( add track elst atom ).

The introduced delay can be correctly playbacked with VLC or Quicktime

player, but the WMS didn’t take into account of this delay. Could you fix

this problem?

We do not take into account elst atoms.


We have no short term plans to add support for this.


No, not on a per-track basis.


At this time there is just no way to do this. We do not have a way to introduce a delay into a video on demand stream.


Could you consider to implement this feature in the WMS?

It is important for our applications. If needed I can provide a

sample MP4 video with the “elst” atoms.

Is it possible to implement some Server Side Module or client module

to give some start delay on certain audio or video tracks?

If so, can you give me some advices?

Charlie, would it be possible to implement a workaround on module level using the MediaReaderListener API? Or perhaps some other way to sync the tracks?

We are ready to get as deep as possible into the API if needed.

This is extremely important for us…

Thank you,