The name of the datachannel is always JanusDataChannel

[Harkanork]

Hi,

Version: Janus v0.11.1

If a publisher creates a data channel with a custom name ('ChatChannel' for example), the OnDataChannel of the subscriber always receives a datachannel withe the name 'JanusDataChannel'.

Expected : The datachannel created on the subscriber side has the good name

Janus Logs:
Janus receives the creation of the datachannel by the publisher
[Mon Feb 22 18:41:26 2021] [4279064680722971] Opened channel 'ChatChannel' (protocol=??, id=1) (0/0/0)

Janus receives a message and send the creation to the subscriber
[Mon Feb 22 18:41:42 2021] [4279064680722971] Incoming SCTP contents: {"author":"Inscape","epoch":1614015702,"message":"super"}
[Mon Feb 22 18:41:42 2021] Got a text DataChannel message (57 bytes) to forward
[Mon Feb 22 18:41:42 2021] Forwarding text DataChannel message (57 bytes) to viewer
[Mon Feb 22 18:41:42 2021] [3366957378648267] SCTP data to send (label=JanusDataChannel, 57 bytes) coming from a plugin.
[Mon Feb 22 18:41:42 2021] [3366957378648267] Outgoing SCTP contents: {"author":"Inscape","epoch":1614015702,"message":"super"}
[Mon Feb 22 18:41:42 2021] [3366957378648267] Creating channel 'JanusDataChannel'...
[Mon Feb 22 18:41:42 2021] Opening channel with label 'JanusDataChannel' (16, protocol )

[lminiero]

Yes, that's normal in the regular demo and with janus.js, because the VideoRoom plugin doesn't use labels when sending data to participants, and re-uses the ones subscribers create themselves (and janus.js uses that name for the default DC). This is not a problem as each PeerConnection can only serve content from a specific publisher, so no matter the label, if data is coming from PC X, you know who it's from. The multistream branch VideoRoom instead uses the publisher ID as the label.

Closing as it's working as intended.

[Harkanork]

Ok, as you want but if I understand the current version of Janus can not manage more than 1 datachannel per publisher, right?
In the multistream branch, why do you force the label of the datachannel instead of using the one given by the publisher?

[lminiero]

the current version of Janus can not manage more than 1 datachannel per publisher

You're confusing Janus and VideoRoom: they're not the same thing. The VideoRoom plugin only does 1 data channel, yes; Janus doesn't have this limit. If you play with the Lua or Duktape plugin to write your own script, for instance, you'll find you have more flexibility there, using different labels to send and receive traffic.

In the multistream branch, why do you force the label of the datachannel instead of using the one given by the publisher?

Because in multistream you can subscribe to more than one participant on the same PeerConnection. Using the participant ID as the label allows the subscriber to know who the data they're receiving comes from (since you may receive multiple data messages on the same PC).

[mircokam]

Hello,
we testet the Android App Talk Version 18.1.0 on Pixel 7 with Janus 1.x Multistream an Nextcloud 28.0.3 and Talk 18.0.5 and nextcloud-spreed-signaling 1.2.3 an it works now with video. :-)

sunweaver/nextcloud-high-performance-backend-setup#109