​screen share randomly not showing on student screen

[jossef]

​Hi Fred and Chad​

with your excellent help and support​ I successfully upgraded my production server ​to beta 17​,  ​the reviews from users ​are very good​,​ they love it​.​ except ​for One major issue​, that ​is: ​screen share randomly not showing on student screen.

​​did not ​find any clue on browser console or log files​.

I see​ same issue on ​BBB ​test server​. (Do F5 a few times, on receiving user, until you see black screen instead of shared screen)

tested on updated Chrome 64bit Win10.

​there is no issue on Firefox​,​ only on Chrome​.​

the only thing that helps​ ​Return the share​d​ screen to student ​​is ​​​​​Ctrl + ​F5​.​

which leads me to believe it is something to do with Chrome​ ​browser ca​ch​e​ ​and session token ​expiration​​​. maybe it is related to the new ping pong​ ​addition.

 I really hope you guys will make better sense out of it​, and fix it ​in no time​.​

B​est regards

Jossef​

[Fred Dixon]

Hi Jossef,

> with your excellent help and support I successfully upgraded my production server to beta 17,  the reviews from users are very good, they love it. except for One major issue

Nice!

> screen share randomly not showing on student screen.

Hmm ... we'd like to dig into this one more.  Is it possible the next time this happens to a user that you ask them to send you a copy of their browser console ... this will help us see if there are any error messages thrown by their client.

Opened an issue to track this

  https://github.com/bigbluebutton/bigbluebutton/issues/7798

Regards,... Fred

--
You received this message because you are subscribed to the Google Groups "BigBlueButton-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to bigbluebutton-...@googlegroups.com.
To post to this group, send email to bigblueb...@googlegroups.com.
Visit this group at https://groups.google.com/group/bigbluebutton-dev.
To view this discussion on the web visit https://groups.google.com/d/msgid/bigbluebutton-dev/21fdf8aa-a970-4386-adf3-6a69c967d8dd%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

--

BigBlueButton Developer

http://bigbluebutton.org/

@bigbluebutton

[jossef]

Hi Fred

 it is easy to reproduce,

 start screen share on 1 client

open new tab, login and Hit refresh button or F5 until you get only black screen in the presentation area.

 I just did, on test.bigbluebutton.org and after about 9 refreshes it happened. (Very random)

if you click Ctrl+F5 it will never happen.

yesterday, when I tested this, I saw this error in the console: 

arguments: [Exception: TypeError: 'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them at Function.invokeGetter (<anonymous>:2:14)]

caller: [Exception: TypeError: 'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them at Function.invokeGetter (<anonymous>:2:14)]

length: 0

name: "getVideoTracks"

Regards

Jossef

בתאריך יום רביעי, 17 ביולי 2019 בשעה 10:11:15 UTC+3, מאת jossef:

[Paulo R. Lanzarin]

I'll try to reproduce and dig into this further, Jossef. I suppose you've reproduced it on Chrome, right? Which version of Chrome and what OS are you on?

Thanks for the repro. steps.

--
You received this message because you are subscribed to the Google Groups "BigBlueButton-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to bigbluebutton-...@googlegroups.com.
To post to this group, send email to bigblueb...@googlegroups.com.
Visit this group at https://groups.google.com/group/bigbluebutton-dev.

To view this discussion on the web visit https://groups.google.com/d/msgid/bigbluebutton-dev/471e4e8e-89d2-499d-8293-be324bf3f074%40googlegroups.com.

[jossef]

tested on updated Chrome 64bit Win10.

​there is no issue on Firefox​,​ only on Chrome​.​

 ​​​​​Ctrl + ​F5​ will ​fix and Return the share​d​ screen.

maybe it is something to do with Chrome​ ​ca​ch​e​ ​or file ​expiration​​​.

Thanks for your help on this

Jossef

בתאריך יום רביעי, 17 ביולי 2019 בשעה 10:11:15 UTC+3, מאת jossef:

​Hi Fred and Chad​

[Paulo R. Lanzarin]

I'll guess it's probably related to autoplay in some way. Anyways, will take a look.

--
You received this message because you are subscribed to the Google Groups "BigBlueButton-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to bigbluebutton-...@googlegroups.com.
To post to this group, send email to bigblueb...@googlegroups.com.
Visit this group at https://groups.google.com/group/bigbluebutton-dev.

To view this discussion on the web visit https://groups.google.com/d/msgid/bigbluebutton-dev/bc9602dc-db46-4d63-8070-0ca40c522b89%40googlegroups.com.

[jossef]

:console officer after screen share disappear

בתאריך יום רביעי, 17 ביולי 2019 בשעה 10:11:15 UTC+3, מאת jossef:

​Hi Fred and Chad​

[Fred Dixon]

Hi Jossef,

We're wondering if the playing of video might be related to Chrome's restrictions on AutoPlay?  

  https://developers.google.com/web/updates/2017/09/autoplay-policy-changes

It might be that the users who could see the video had already shared their webcam (and thus giving permission to Chrome to send/receive media.  

Do you have a user that consistently can not see the shared screen?  If they share their webcam, do they see the shared screen going forward?

Regards,... Fred

--
You received this message because you are subscribed to the Google Groups "BigBlueButton-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to bigbluebutton-...@googlegroups.com.
To post to this group, send email to bigblueb...@googlegroups.com.
Visit this group at https://groups.google.com/group/bigbluebutton-dev.

To view this discussion on the web visit https://groups.google.com/d/msgid/bigbluebutton-dev/0ca4e7cd-b3b0-446a-865b-fae2db322f40%40googlegroups.com.

For more options, visit https://groups.google.com/d/optout.

[jossef]

users connected "listen only" after teacher lock mic, and didnot use webcam.

you are absolutely correct ​!  Chrome autoplay policy is causing the problem.

​in chrome//flags/  page, I disabled autoplay policy and enabled auto play ignores web audio playback

and now screen share ​is always appearing and there is no more​ ​problem. even after  20 times I refreshed the page.

so I guess ​you ​should make the client comply  with chrome autoplay policy,
Maybe an ​"​accept​"​​ ​ button on ​user ​screen​ on login, 
and add video controls​ on ​player's window. 

בתאריך יום רביעי, 17 ביולי 2019 בשעה 10:11:15 UTC+3, מאת jossef:

​Hi Fred and Chad​

[jossef]

Hi Fred 

after few failed sessions I'm receiving requests from teachers to revert back to the flash client :(

hope there soon  be a solution to this critical autoplay issue.

 in the meantime, Is there any script to add to the client, that can help?

best regards

Jossef

בתאריך יום שישי, 19 ביולי 2019 בשעה 16:16:26 UTC+3, מאת jossef:

[Fred Dixon]

H Jossef,

We're working on a solution now (I don't have a time estimate, but we want this fixed too!)

In the meantime, for any student that does not see the screen, a quick refresh should start displaying it.

Regards,... Fred

--
You received this message because you are subscribed to the Google Groups "BigBlueButton-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to bigbluebutton-...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/bigbluebutton-dev/52d96d63-e325-444a-9fee-20828465d418%40googlegroups.com.