Why is BigBlueButton slow on GuixSystem (was: Re: Thank you for participating in the Guix Day!)

[Jonathan Brielmaier]

On 25.11.20 19:24, Leo Famulari wrote> On Wed, Nov 25, 2020 at
06:50:41PM +0100, Michael Rohleder wrote>> Browser is icecat
78.5.0-guix0-preview1 with all extensions disabled,>> except
"Surfingkeys".>>>> Computer is something like this (neofetch):> > [...]>
> Hm... it seems unlikely that this computer, which is relatively>
powerful, couldn't handle it. I suspect a bug in the browser.
My educated guess would go more into the decoding with/without hardware
acceleration topic.

In video conferencing clients need to do video encoding (when they use
their webcam) as well as video decoding in real time. This can be pretty
resource hungry (CPU) especially when there is no proper HW acceleration
by the GPU.

Don't make the mistake to compare to YouTube. It's a different situation
because Google does (almost) everything possible to make the decoding
less demanding for the clients. That's not so easy when you do real time
encode+decode.

According to their FAQ[0] 1Mbit/s download and 0,5Mbit/s upload are
recommended.

For audio they seem to use OPUS and VP8 for video with fallback on h264
(not sure if enabled by default).

BBB uses WebRTC quite heavily, maybe that is the key problem. It can be
tested via [1][2].

On Guix System my Firefox has set following params in about:config:
```
gfx.blacklist.webrtc.hw.acceleration.decode.failureid ->
FEATURE_FAILURE_GLXTEST_FAILED
gfx.blacklist.webrtc.hw.acceleration.encode.failureid -> FEATURE...
gfx.blacklist.webrtc.hw.acceleration.h264.failureid -> FEATURE...
```

Maybe VA-API can help[3]...

So far from me
Jonathan

[0]
https://docs.bigbluebutton.org/support/faq.html#what-are-the-minimum-requirements-for-the-bigbluebutton-client
[1] https://test.webrtc.org.
[2] https://networktest.twilio.com/
[3]
https://mastransky.wordpress.com/2020/09/29/firefox-81-on-fedora-with-va-api-webrtc-and-x11/