Video Lag, audio stutter/slur when presenting by sharing a screen

[GracieAllen]

I’m a member of a photography club that has a Zoom license for meetings.  We typically have between 15 and 30 participants at the meetings. 

In a Zoom meeting that’s limited to conversation, we infrequently encounter any problems with video lag or audio stuttering/slurring/dragging.  But in presentation meetings where the presenter is sharing a screen or even just a window, we frequently get very bad multi-second video lag.

It happened most recently last evening when I was presenting some editing techniques in Lightroom.  I shared a window in 16:9 aspect ratio, and used a connection of around 18-20Mbps.  My system is an i9-12900, AMD 5700 XT GPU, and 64GB of memory running Windows 11 Pro, but the same thing happened with Windows 10 Pro prior to the upgrade.  I never saw system usage exceed 15%, and whenever I checked the bandwidth I always had at least 18 Mbps available.

I don’t THINK there’s a problem on my end, but I'm not sure I'd have any way of knowing.

Participants who were watching the presentation reported significant video lag throughout the presentation, to the point where many viewers were unable to follow what I was doing.

A short time ago, another member presented some images – no editing, just a display of images sized to fit on a monitor – these were not large images.  His audio described the images, and we experienced the same kind of significant video lag.  I don’t know the specifics of the system or connection he was using, but I believe it’s a current system with more than adequate resources.

Neither of the above are unique.  This happens frequently when we do any kind of screen sharing or presentation.

In my search, I found a number of other entries talking about similar issues, but didn’t find any pointer to a defined procedure for determining the origin of the problem and correcting it.

Audio problems occur randomly even when engaged in simple conversations with a couple dozen participants.  It’s not constant, but it is periodically audio will slur and drag out words.  This occurs at times when no one is sharing a screen or doing anything unusual.

Does the presenter’s screen resolution impact the video lag, or only the people watching the presentation?  I’m using a 4K screen, but sharing a 16:9, 2800x1600px window.  Do I need to create and share a SMALLER window that’s 1920x1080 for sharing?

Do people receiving the presentation need to reduce THEIR screen resolution below 1920x1080?

Does the number of people watching the presentation impact the occurrence of video and/or audio problems?

Does having participants turn off their video and mute their microphone reduce the likelihood of encountering video and audio problems?

Is there something that can be done in settings or configuration that will correct this video lag problem?  Do “beauty mode” and/or video filters affect the screen share and increase the likelihood of having problems?

[RN]

Hi @GracieAllen, lag spikes happen, I have them once in a while too. If you're curious while hosting you can break down your meeting statistics from your Zoom client Settings > Statistics. For more info on meeting statistics. There's really no telling as to what could've happened without analyzing the meeting and investigating from our Zoom technical support. 

Setting wise for your screen share issue, ensure you 'share computer audio' and 'optimize for video clip' when sharing content. You can also try within your Zoom desktop client settings under 'Share screen' click on 'Advanced' and check or uncheck, "Use Hardware acceleration to optimize video sharing", and see if that changes or makes a difference for your Screen sharing experience. Along with Checking or Unchecking, 'Use TCP Connection for screen sharing'

Here is also some useful network troubleshooting and suggestions https://support.zoom.us/hc/en-us/articles/201362463

Zoom sends and receives 1080p video, so the resolution of your displays shouldn't be an issue, and based on your setup, any CPU and GPU usage should be fine. During a meeting, your connection is solely dependent on your own network, not on the network of others or the meeting host; therefore, other participants may be experiencing network issues as well.

[GracieAllen]

I’m familiar with some minor lag occasionally.  This was not.  It appears that essentially everyone watching the presentation was treated to an hour of massively mismatched audio and video, with my words, mouse, and screen all being out of sync.  Frequently, watchers could see the mouse moving long before the screen image caught up.  Unfortunately, NO ONE spoke up to tell me the presentation was complete gibberish until after it ended.

Previously, with the presenter that was just sharing pictures, there was no mouse, but the discrepancy between the voice and screen was almost constant and significant.  We finally resorted to him telling us when he moved to the next image, and one of us telling him when it appeared so he could describe it.

I’m afraid I’m a little befuddled as to what account is being used to do whatever…

I’m not the meeting host, I don’t initiate the meeting.  I receive a link that I click to join the meeting.  I believe I’m asked something about “computer audio” when I join, and if so, I have it do so. 

Is the “Zoom desktop client” the thing running in my browser?  If so, is it in any way connected to the local account I can log into on my computer?

Are the “share computer audio”, “optimize for video clip”, “hardware acceleration” all inside the “Share screen” on the desktop client?  Or are they somewhere within my local Zoom?  I’m currently logged into that and I don’t see ANYTHING about “share computer audio” in the Audio section or “optimize for video clip” in the video section.  I DO have check boxes for “Use hardware acceleration for” Video processing, Receiving video and Sending video – all 3 are checked.  There IS an “Optimize video quality with de-noise” but that is Unchecked.

Same question about “Use TCP Connection for screen sharing”.  On the “Share Screen” tab I have settings for Use TCP connection, which was unchecked but is now checked.  And “Use hardware acceleration” for screen sharing, annotations, and “to optimize video sharing” – those are all checked.

As for “statistics”.  How and where do I see them?

----------------------------------------------------

As an experiment, using my local Zoom account, I started a meeting.  MY desktop is the only device connected to a 20Mbps DSL.  It is hard-wired, NOT wifi.

My laptop became the other participant.  It is running on a separate wifi connection through a cell connection that Speedtest currently shows as having 16 Mbps available for download.

On my desktop I have created a 1920x1080 window in which I have Lightroom running.  My screen sharing is set to Optimize for video clip.

Doing the most basic operation – cycling through previews – which are in the center section of the Lightroom window, and are approximately 1024x768px causes a lag of approximately 1.8– 2.5 seconds per switch.  So, the image appears on the laptop approximately 2.5 seconds AFTER I press the key and the new image appears on my desktop.

The mouse is equally laggy, if not worse.  At times, while moving the mouse, I had 3 or 4 cursors visible momentarily.  The cursor jumps to the new position, but a second cursor remains at the old location, then slowly moves to the location where the cursor now is and merges.  This takes well over a second, depending on how far I move the cursor.

I tried sharing a portion of the screen instead of a window.  This would be, by far, the preferred way to do this since I would not have to re-share the screen every time I change applications.  Unfortunately, performance even when sharing the same 1920x1080 portion of the screen is even worse.  Cycling from preview to preview causes a lag of between 4.8-5 seconds PER switch.  So each image takes about 5 seconds after I press the key and the new image appears on my desktop, before it shows on the laptop.

If I zoom in so the preview fills the available preview space, so the preview is approximately 1200x800, the lag gets worse, becoming between 5.5 and 6.2 seconds.

I switched the laptop from the dedicated cell connection to the WIFI from the DSL.  Performance remained the virtually the same, with the lag in a 1920x1080 window being between 1.5 and 2.2 seconds.

Essentially, Zoom is unusable for me to do demonstration presentations, even in the small window I’m using.  And it gets worse if I share a portion of the screen.

Is this simply that my DSL connection is inadequate for me to source presentations?  Or is the data connection to the viewing laptop inadequate?  Or something else?

[newperennialist]

I can relate to your presentation issues because I've been experiencing similar problems on Zoom in making Keynote presentations with various groups via Zoom Webinars and Meetings. 

I cannot tell whether it is the content and size of files or the internet connection that is causing the issue or an inherent flaw in the Zoom Platform. I am presenting on both DSL and also fiber optic Internet connections – and seem to get the lag issues either way. 

If you get a fulsome reply from support, I hope to catch the answers. Thanks!

[GracieAllen]

I finally got a reply from Zoom.  Unfortunately, it WASN'T useful - just the start of what I expect to be a series of hoops to jump through.  They want a bunch of information and authorization to access the meeting - which I don't think I have.

In the MEANTIME, I did a bunch of exploring, and did several things:

I rebuilt Lightroom in the LOWEST size of previews available.  So, I dumbed down the software hugely.

I ran Lightroom in a 1920x1080 window on my screen.  So, the dumbed down software is in a small portion of the screen.

I turned OFF Share audio and optimize for video clip.  Having these on creates huge lag.

In my settings I turned on "Use TCP..."  I don't know if that's doing anything or not.

I have hardware acceleration turned on for everything.  Again, I don't know if that's helping, but I figure it can't hurt.

We've done two test sessions with a dozen people, and the lag is now largely reduced.  It's low enough that using a mouse and moving from image to image is now possible.

One of the things that still DOES NOT work is using "portion of screen".  As soon as I switch to that, even in the small 1920x1080 window, I immediately get a significant lag, though not as bad as previously.

We DID find when testing that MOST of the other users saw the images quickly.  A FEW got a "loading" message that displayed on their screen for a short time.  So, MOST of the users worked well, a few MAY have some bandwidth or other issue on their end?

I'll probably know more Wednesday when I have another technical session for which I'll be using Lightroom and other image editing tools.

[Marsha5]

Thanks for raising this issue. I have found that converting Keynote to Powerpoint helped somewhat with this issue, although it still remained.

[newperennialist]

Good to hear you've gained some improvements. From what I can deduce, yes it's true that other users experience is influenced by their own bandwidth issues – whether sharing screen or simply in the meeting as passive observer. Another small thing that might help is to deactivate your camera while presenting, to help optimize your voice and screen sharing. 

It's also worth mentioning that you should get a superior presentation experience by upgrading to Zoom webinar vs. meetings. Although I've also experienced the lag issue in webinars as well... sigh. 

[andryram]

Yes, I have also encountered the same issue. When I was teaching editing in Lightroom to one of my friends, I faced lagging. It was working fine with other screens. I didn't face any lagging when I shared other screens. So it was the problem with the Lightroom I was using. So I downloaded the Lightroom latest version again and finally, the issue got resolved. It was the Lightroom version issue.