[Standards] Re: Proposed XMPP Extension: Jingle Audio/Video Conferences

Hi, Thanks for proposing this specification. I still fail to see why it is necessary or a good idea to create a new Jingle session for every participant stream. I see a lot of downsides without any obvious upside. As I understood, the reason to do this is that some SFU implementations use one WebRTC session per participant. However, there is no rule that says that a WebRTC session corresponds to a Jingle session. It's perfectly valid to translate multiple WebRTC sessions to multiple contents in a single Jingle session. There's no way for a client to know if an incoming call is part of already running conference call or independent, except for comparing the from-attribute if the iq stanza of an otherwise unrelated Jingle session. As of now, a single device can (technically) have multiple independent Jingle sessions and calls, even multiple between the same JIDs. While there probably aren't a lot of usecases for that (except for file share + single call at the same time), it seems inappropriate to disallow this by giving two calls with the same entity a special meaning (aka saying they form a conference) which is effectively what this XEP does. When multiple sessions are used, each stream needs to negotiate an additional ICE (+DTLS) session, because BUNDLE grouping is only defined within a Jingle session, not across sessions. This means unnecessary delay when new participants join. I understand that some available SFUs don't BUNDLE different participants, but that doesn't mean it's always a bad idea to support that. The current design doesn't allow the SFU to mix audio signals. While mixing is not strictly a task for SFUs, hybrid SFUs that mix audio and forward video are not uncommon for large A/V setups, so supporting this also would be reasonable. COIN already does support to announce audio mixing, but that by design wouldn't work if each participant needs to get their own Jingle session. Marvin On Tue, 2024-08-06 at 15:06 +0000, Daniel Gultsch wrote: