Videoroom: slow link events on subscribers

General
1

I’d like to make sure I properly understand how slow_link events work with the videoroom plugin.

I get that receiving this event on a publisher means that, Janus is not properly receiving all the data from the sender. One could decrease the sender bitrate/resolution/etc to hopefully improve the situation.

It’s not that clear to me what it means to receive this event on a subscriber.

  • Janus is not able to send all the data to the subscriber?
  • or is the publisher linked with this subscriber which is having sending problem and this info is forwarded to all subscribers receiving this stream?

If it’s the former, then one way to handle it would be to request a lower quality stream when using multicasting.
If it’s the latter then we need to change the publisher settings as when receiving the event for publishers.

Does that make sense or did I missed something here?

2

Yes.

No. A subscriber handle has nothing to do with what’s feeding it (which may be multiple publishers anyway, in multistream).

3

Or, to be more precise: Janus is being notified about issues sending data to this subscriber. Whether the cause is actual packet loss, or data the publisher is not sending (and so Janus not relaying) slow_link cannot know. It’s up to you to monitor (e.g., via event handlers) and perform the proper correlation on both ends.

4

Thanks for your quick reply!

Can I safely assume that I will always first receive a publisher event, before the subscriber ones, if the problem is on the publisher side?

5

In theory, yes. Of course, if users have direct access to the Janus API, the publisher event and the subscriber event will not b received by the same person.

6

Perfect. I have my own server between users and Janus so that should be fine.

Thanks for your help.