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by pthatcherg 1565 days ago
Hey, I'm the author of the Signal blog post about SFUs. I have a few questions/comments:

1. I don't think there are many good open source SFUs to choose from. I know of 2, maybe 3 (including our new one). There may be many, but few have good rate control. But maybe I just don't know about them? I'd be happy to learn of more good ones.

2. Echo cancellation is certainly a hard problem, but it doesn't conflict with E2EE unless you do it on the server, which isn't necessary. So perhaps it may be a somewhat harder problem because you close off one possible approach (doing it server-side), but many (most?) echo cancellation solutions are done client-side.

3. You may not be completely dependent on WebRTC's echo cancellation any more because of the new MediaStreamTrackProcessor and MediaStreamTrackGenerator APIs. I don't know if it will work for echo cancellation, but it might.

1 comments

1. So the SFUs we're currently looking at are yours, ion-sfu (and/or galene) and mediasoup. Honestly we haven't finished looking at how they compare for rate control, but the Pion team seems very interested in ensuring they have good rate control.

2. From context I think you're talking about noise cancellation here? I assumed that some of the more exotic ML-based ones ran serverside, which obviously is incompatible with E2EE. It sounds like there are a bunch of options for running WASM-based intelligent noise cancellation clientside though, especially with MediaStreamTrackProcessor and friends. rnnoiseless as a pure Rust->WASM port of rnnoise looks fun, for instance: https://github.com/jneem/nnnoiseless

3. True, although given Google are highly motivated to make AEC work properly in WebRTC, I guess I'm hoping that they'll continue improving it, much as they have been. I certainly never want to have to write or integrate one ever again :D