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:
> The XMPP Extensions Editor has received a proposal for a new XEP.
>
> Title: Jingle Audio/Video Conferences
> Abstract:
> This specification defines a way to hold multiparty conferences with
> an SFU via Jingle.
>
> URL: https://xmpp.org/extensions/inbox/av_conferences.html
>
> The Council will decide in the next two weeks whether to accept this
> proposal as an official XEP.
> _______________________________________________
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