Signal-Calling-Service VS galene

I am npt sure if this is related but Signal built Signal Calling Service and according to them it worked great.

I was curious and looked through the code of Galene briefly and found the following, which may answer your question. For context, I am familiar with the Jitsi code and have written my own calling server (and written about it: https://signal.org/blog/how-to-build-encrypted-group-calls/).

Galene appears to be less mature than Jitsi. For example, it uses REMB feedback messages from the client to calculate allowable bitrates rather than calculating the bitrates itself (as Jitsi and Signal's SFU do). Worse, it appears that what it does with that information is erroneous. I could be wrong, but it looks like the bitrate allocation code (see https://github.com/jech/galene/blob/e8fbfcb9ba532f733405b1c5...) only allocates the bitrate for one of the video streams, not all of them. Perhaps the author did not realize that there is one REMB sent back for all the video streams by WebRTC rather than one per stream (see, for example, here: https://source.chromium.org/chromium/chromium/src/+/main:thi...). Further, I find the spatial layer switching code to be strange. For examples, it doesn't go down a layer unless it's 150% over the estimated allowable bitrate, which gives a lot of opportunity for inducing latency.

In short, I think Galene has a ways to go before it works as well as Jitsi (Videobridge), and thus Pyrite group calls are unlikely to work as well as Jitsi group calls (for 1:1 calls, I don't know; I didn't look into that).

Oh, and just a reminder, the SFU we use for Signal group calls is also open source: https://github.com/signalapp/Signal-Calling-Service.

And yeah, it uses Signal-Calling-Service written on Rust.

That's a well written article covering the basics of simulcast.

If you're interested in seeing an implementation of an SFU doing simulcast forwarding written in Rust, we (at Signal) recently open sourced our SFU:

https://github.com/signalapp/Signal-Calling-Service/blob/mai...

I would like to recommend Galene: https://github.com/jech/galene

Runs in my raspberry pi, a single small executable, like in the old good times.

> Do you happen to know of others by any chance.

There's Galene, <https://galene.org>. It's easy to deploy, uses minimal server resources, and the server is pretty solid. The client interface is still a little awkward, though. (Full disclosure, I'm the main author.)

galene - basically selfhosted zoom/jitsi

What latency are you trying to do? Will the professor being communicating with the students while doing this? Will the students all have the same bandwidth, or will you want multiple renditions (low, med, high quality levels)?

If you want AV1 you will not be able to use RTMP. The protocol is orphaned/deprecated, so avoid if possible!

If I was building it this is what I would do, and my reasoning.

* For capture + encoding I would use OBS. You will want to use something that is easy for users to install configure. Professors will also have lots of custom requirements when it comes to layout etc... it will be tempting to do a ffmpeg command directly, but it will fall apart quick I believe.

* To get AV1 out of OBS I would use FFMPEG output. I would have it send RTP. RTP is used to carry video in a sub-second manner. This is the same protocol that WebRTC uses. You know have AV1 + low latency.

* Then for users to watch I would use WebRTC. That will allow them to watch in their web browser. Conceptually it will be like this https://github.com/pion/webrtc/tree/master/examples/rtp-to-w... this takes the RTP packets and puts them in the browser.

Lots of great projects exist that you could use for 'RTP -> WebRTC' like https://galene.org/ and https://livekit.io/ I would suggest checking them all out!

If you have more questions/want to talk to people in the video space always happy to chat on https://pion.ly/slack :)

galene

The most lightweight all-inclusive central solution for video conferences I know is Galene. It runs in under 200 MB RAM.

Even though the default UI is extremely simplistic, I very much like galene. It bundles all the components you need in a single binary. Even a TURN server so you don't have to fiddle with coturn. Not to mention that it's very resource efficient.