Technical question Zoom vs MS Teams - help!

[RevdKathy]

So a year into this pandemic working from home malarkey one of my team is complaining that work meetings give her migraine. Nothing too surprising there. All that staring at screens gets to us all (I have online meetings stacked so tight tomorrow I'll be lucky to get a bathroom break between them).

However, when pressed about the amount of her free time she chooses to spend in online meetings she announced that she doesn't get migraine from zoom, only from MS Teams. Which of course is what work requires us to use (to the point of blocking zoom from work devices because of security holes).

I suspect she's not connecting via her work laptop anyway, but rather using either her own macbook or iPhone. And her bandwidth up where she lives is terrible - not much better than dialup. That's all I know about the background kit.

So my question to the technical experts of the board is this: before I deduce that she just doesn't want to attend work meetings, should I consider some technical difference between the two platforms? Something below visible like a variation in refresh rate or flicker?

I have searched the web and all the comparisons focus on pricing and features. I need someone who can drill down into the technicalities in case there really is a reason why one causes migraine and the other doesn't.

Please help!

 

[Asbo Zaprudder]

The bandwidth requirements for both Zoom and Teams are similar - about 0.6 Mbps for low resolution 320p at 30 fps, 1.2 Mbps for 720p at 30 fps, and 2.5 Mbps for HD 1080p at 30 fps. Zoom uses the Scalable Video Coding (SVC) protocol and Teams uses the Advanced Video Coding (AVC) protocol. It's possible that SVC copes better with low bandwidth connections, varying bandwidth speed, or noise and so produces fewer glitches and other artefacts that might cause stress to the optical centre of the brain when trying to process what's displayed onscreen.
Migraine - Causes - NHS (www.nhs.uk)

I found this general advice online for avoiding migraines caused by Zoom:
Zoom and Migraine: Tips to Protect Users With Sensory Sensitivities - TheraSpecs
I assume some of the advice is also applicable to Teams.

Beyond that I couldn't say.

 

[RevdKathy]

Thank you! That's really helpful. Yes, I had collected the link about sensory sensitivities and saved the bit about 20-20-20. Not sure how you look 20 feet indies. Through a window?

If there's a potential technical reason I'll suggest the team try meeting via zoom next week.

 

[Asbo Zaprudder]

Of course, I'm not suggesting that the brain having to work hard to cope with jerky video is the direct cause of the migraine as there are no pain receptors in the brain. My speculation in this case is that increased oxygen demand by the visual cortex and muscles in the eyes (trying to follow the edges of flickering macroblocks interpreted as movement) leads to an increase in blood pressure in some areas of the head and the consequent symptoms. However, as the NHS site states, the exact cause is unknown.

 

[Non Sync]

Another possibility is frame rate vs. power frequency. The UK uses 50Hz power and there could be interactions occurring.
Are they also using an older CRT monitor vs. flat panel monitor? The refresh rate could also be an issue.

I know with CRT's set for 60 fps would almost make me barf.

 

[RevdKathy]

She reckoned the work laptop, which would be about 4 years old was worst. IPhone better, but she usually uses the macbook which is less than a year old. I think both streaming services use 30fps, so wouldn't account for the difference.

She's going to try on the iPhone tomorrow to see if it helps. I'll let you know if it makes any difference!

 

[Non Sync]

There is sometimes a setting for the camera for selecting the flicker rate for lighting, particularly florescent.

 

[Asbo Zaprudder]

Most LED lighting driven by DC doesn't flicker much if at all - there might be some residual ripple after converting AC to DC. Any lighting driven directly by AC (such as fluorescent lamps with magnetic ballasts and traditional incandescent lamps) flickers at 100 Hz, not 50 Hz, because the peaks in power (proportional to voltage squared) occur at twice the mains frequency (50 Hz in the UK). The beat frequency for a camera operating at 30 Hz is thus 100 - 30 Hz, that is, 70 Hz. However, more modern fluorescent lighting with electronic ballasts operates at higher frequencies between 20 and 60 kHz for efficiency. These higher frequency lamps are preferred for people with medical conditions such as autism, chronic fatigue syndrome, epilepsy, lupus, Lyme disease, migraine, and vertigo.

 

[RevdKathy]

That's interesting... I wonder whether the lighting from someone else is causing flicker.

It's not me, I seldom have anything but natural light.

 

[Non Sync]

I've observed auto LED headlight flicker with me rearview mirror camera.

 

[Asbo Zaprudder]

I've observed auto LED headlight flicker with me rearview mirror camera.

Weird as a car headlight would be powered by DC.

 

[Non Sync]

Most LED lights actually switch on and off as part of their normal operation. Running the LED at 100% duty cycle shortens its life (higher current draw, additional heat), so having it switch on/off very quickly increases the lifespan.

 

[Asbo Zaprudder]

Doh, of course they do. I'd forgotten that. In fact to dim them, they have to be switched. I thought the switching frequency was in the hundreds or thousands of hertz but a digital camera is probably able to capture instances when the LED is off in its duty cycle. Yes, the darn things flicker so there are potentially physiological effects. In fact, as it's on-off cycling and not pure sine wave, the effective frequency range is broad.

In some instances, LED lighting can interfere with wi-fi but it's not the lamps themselves that are the problem but existing DC supplies when halogen lamps are swapped for LED lamps. [Radio, TV or WIFI interference with LED lamps - Kosnic] This might reduce the usable bandwidth, degrading the quality of a conferencing connection.

 

[CorporalCaptain]

So a year into this pandemic working from home malarkey one of my team is complaining that work meetings give her migraine. Nothing too surprising there. All that staring at screens gets to us all (I have online meetings stacked so tight tomorrow I'll be lucky to get a bathroom break between them).

However, when pressed about the amount of her free time she chooses to spend in online meetings she announced that she doesn't get migraine from zoom, only from MS Teams. Which of course is what work requires us to use (to the point of blocking zoom from work devices because of security holes).

I suspect she's not connecting via her work laptop anyway, but rather using either her own macbook or iPhone. And her bandwidth up where she lives is terrible - not much better than dialup. That's all I know about the background kit.

So my question to the technical experts of the board is this: before I deduce that she just doesn't want to attend work meetings, should I consider some technical difference between the two platforms? Something below visible like a variation in refresh rate or flicker?

I have searched the web and all the comparisons focus on pricing and features. I need someone who can drill down into the technicalities in case there really is a reason why one causes migraine and the other doesn't.

Please help!

Just for the sake of considering all options:

https://en.wikipedia.org/wiki/Virtual_reality_sickness

I can't comment on whether it's a factor here, but it might be worth considering.

 

[publiusr]

I swear I have seen flatscreens have the same artifacts that CRTs seemed to show on video footage. Only twice though