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From: "Michael Ströder" <>
Subject: [Galene] Re: fq-codel trashing
Date: Wed, 13 Jan 2021 20:09:25 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 1/12/21 10:22 PM, Juliusz Chroboczek wrote:
>>> We just had a meeting with 70 people and at around 40 cameras switched on,
>> Which send quality were they all using? "normal"?
> The quality selected in the menu is the maximum allowable quality; Galène
> will rather eagerly drop down beneath it, all the way down to 200kbit/s
> (it will drop quality even more aggressively in the future).  So we were
> running at "normal", but the resulting bitrate was somewhere between "low"
> and "lowest".

But if users are thrown out of sessions and reconnect the browser will
again try a higher send rate. Right? If that happens to several sending
users within a short time-frame you will get some peaks affecting all
the receiving users. Well, I'm speculating here.
(This reminds me of tuning of feedback control systems.)

>> We had one hearing impaired user who hears a little bit with in-ear
>> devices. Normally the user also follows spoken text by lip-reading to
>> get more context. But this is nearly impossible for her in a video
>> session because audio and video are not sufficiently synchronised with
>> our setup.
> Hmm... was that with Galène?  Which browser?

Yes, with Galène. I don't know which browser was used though.

> In principle, Galène generates all the bits of protocol to perform
> accurate lipsynch on the receiving side.  I have veryfied that it works
> well with Chrome.

I'm not really capable of lip-reading, so I can't tell which quality a
lip-reading user would need. But there was some visible jitter even
within my LAN with just a one-to-one test.

Maybe I can contact this user to do dome specific tests...

>> Not sure whether that's really a fairness issue within Galène. I
>> can see differing latencies in /stats for different connections.
>> The connection with higher latency, most times on all "Down"
>> streams, has the higher latency consistently throughout whole
>> session. I suspect the receiver side is the issue.>
> You might be mis-reading the statistics.

Yes, maybe.

>  For an up stream, Galène only
> keeps track of the amount of jitter.  For a down stream, Galène keeps
> track of both average delay and jitter.
> Up:   ±3ms     means 3ms average jitter;
> Down: 30ms±3ms means 30ms average delay with 3ms average jitter.

This matches my interpretation. As said the average down-stream delay
was consistently higher for users having issues.

Most users here are using the usual VDSL or cable-TV connections within
Germany. I have no knowledge whether some users are still using slower
DSL lines.

For connections/users without issues I see average down-stream delays of
40..60 ms with jitter 10..40 ms.

Users reported no problems even with down-stream delays of 100..150 ms.

Real problems start when average down-stream delays is 150+ ms most of
the time.

Ciao, Michael.

  reply	other threads:[~2021-01-13 19:09 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-12 13:46 [Galene] " Juliusz Chroboczek
2021-01-12 15:55 ` [Galene] " Toke Høiland-Jørgensen
2021-01-12 16:01   ` Dave Taht
2021-01-12 17:38   ` Juliusz Chroboczek
2021-01-12 17:42     ` Dave Taht
2021-01-12 18:10       ` Juliusz Chroboczek
2021-01-12 19:05         ` Dave Taht
2021-01-12 19:52           ` Michael Ströder
2021-01-12 21:02           ` Juliusz Chroboczek
2021-01-12 19:29         ` Michael Ströder
2021-01-12 21:22           ` Juliusz Chroboczek
2021-01-13 19:09             ` Michael Ströder [this message]
2021-01-14 12:59               ` Juliusz Chroboczek
2021-01-14 13:03                 ` Michael Ströder
2021-01-14 13:10                   ` Juliusz Chroboczek
2021-01-14 13:23                     ` Michael Ströder

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