Tech Tips for Zoom University: Get a Good Mic, But Your Camera Doesn't Really Matter

Zoom compresses all video uploads, turning the most high-definition stream into grainy video

Over the summer, I investigated whether I could use a higher-resolution camera to obtain a high-resolution Zoom feed. Ultimately, I abandoned the project. Why? Zoom automatically caps your upload quality:

As our world comes together to slow the spread of COVID-19 and stays connected through Zoom globally, we are working to quickly scale our bandwidth during this unprecedented demand.

For the time being, standard video, not HD video, will be activated when 3 or more participants join a group meeting. HD video (720p) will be activated for 2 participants or when a Zoom Room or Conference Room Connector joins a group meeting. HD video (1080p) will only be activated for selective use cases such as large format broadcast events.

In short, it doesn't matter what kind of camera you use. Zoom will not let you broadcast in HD. Better lighting could help to reduce shadows, but the quality will still look like a grainy RealPlayer stream from the early 2000s.

The only technology that makes a difference is your microphone. Audio quality really matters. I currently use the Pyle PDMIUSB50 microphone. It sells on Amazon for about $55.

Comments

[santamonica811]

Strange. I've been doing Zoom games nights during Covid. And doing occasional chats with Volokh and friends--also via Zoom.

These videos have not looked the tiniest bit grainy to my eyes (which might say more about my own visual acuity than anything in Josh's post, I admit). Certainly not high-def. But perfectly clear, and miles away from the genuinely-poor-quality 15-to-20-year-old streams Josh references.

[Dr. Ed 2]

Remember too that your local machine will degrade image quality further when necessary due to either shortage of its own internal resources (e.g memory) and/or upload bandwidth. Memory is cheap and if you can increase yours, just do it.

Also there is the question of how much else you have open on that computer and even how much it is clogged with .tmp files. None of this is as bad as it was 30 years ago, or even 10, but you would be surprised sometimes. Also any major drain on resources can be indication of a virus (or a virus scanner doing something it ought not, or two fighting with each other).

As to the upload bandwidth, you could always do a traceroute and/or ping to Zoom's IP and see if you see a bottleneck somewhere. Or, better, chat with your univ's IT folk because you probably aren't supposed to know how to do a traceroute and you actually can cause some problems with ping if you let it get into an endless loop.

My point: Image quality is always given as a maximum, but things at your end, or in between you and Zoom can reduce it Think a busy interstate highway and what a wreck does to traffic flow.

[Dr. Ed 2]

One other thing, "compression" doesn't inherently -- itself -- affect image quality.

Compression ONLY involves literally compressing a file into a smaller file which is smaller and hence easier to transmit. (NB: It must be uncompressed at the other end before it can be used.)

Now if you are running low on resources (memory comes to immediate mind) and getting buffer overruns, I can see your machine intentionally degrading the size (and hence quality) of the video images it is recording so as to remain within its ability to compress and ship them.

Now Zoom-R-Us may be using the word "compression" to mean something else, but file compression, if it is working properly, should not affect the uncompressed file at the other end (and if it isn't working properly, you get garbage at the other end because checksum can only guarantee the accuracy of the compressed packets).

I apologize if I've gone too far into the weeds -- and I didn't add all the "but then, if" stuff -- I'd go chat with your college IT folk, particularly if you have enough memory. It's always more than the programs say you need, and MicroSquish Office is particularly notorious in that regard.

[arch1]

“...but file compression, if it is working properly, should not affect the uncompressed file at the other end...”

This is true of so-called lossless compression algorithms (and is in fact their defining chacteristic), but it *isn’t* true of lossy algorithms such as that used by JPEG.

Why would anyone use a lossy algorithm? Because in comparison with lossless compression algorithms, they tend to use much less space and data transmission time for typical data, and they can even guarantee a given compression ratio, at the cost of losing some image information (which, depending on the information lost and the needs of the application, may be a very beneficial tradeoff).

( A familiar toy example of this is the coarsely pixellated grayscale image of Lincoln, which despite being compressed by a factor of thousands relative to a high resolution grayscale image, still does the job of evoking the visage of Honest Abe to most people familiar with his appearance).

[KHP54]

No it doesn't ONLY do that; especially when we aren't talking about file compression in the first place.

Video compression is a completely different animal, with near-realtime requirements almost as stringent as for audio.

[Commenter_XY]

SM811...A funny story. I do a lot of video calls (usually on MSFT Teams). I had an eye exam because you know, once you pass a certain point in life, your body just starts breaking down. Yeah, my eyes are starting. I finally got glasses (circa mid-fifties). You know what happened? Every video calls now looks High-def regardless of platform. 🙂

[Eddy]

And when you get a good mic, don't forget to get two turntables.

https://www.youtube.com/watch?v=EPfmNxKLDG4

[Chris Upchurch]

While a higher resolution webcam doesn’t really get you much with Zoom, there are still benefits from a higher quality camera. The biggest of these is an ability to handle a wider range of lighting conditions. Indeed, I switched from using the internal webcam in my iMac to an external Logitech one in May for just this reason. The Logitech does a much better job for quick video calls where I don’t bother to close my blinds or use my full lighting setup.

[Dr. Ed 2]

There is also something called magic, otherwise known as bizarre things that computers do for reasons that you simply can not understand. I'd try a cheap external webcam to see if there is any difference because it's not going to be connecting exactly the same way and its entirely possible that it might work better.

You could have a bad camera. Or any of the soldered connections or chips or boards might have a slight problem. If you fix the problem, then it works.

[Dr. Ed 2]

One other thought -- if a computer is overheating, the bizarre things it will do can be limitless (and damn hard to figure out).

The 486 chips were the worst ones (including the dual platform Macs) and the nice thing about the Energystar standards is that using less electricity produces less heat.

It is still possible to overheat them, particularly a laptop if you put it on a tablecloth or something that obstructs the fan inlet on the bottom. I've also seen tower computers on the floor suck in so much dust that there is little air getting through.

[tkamenick]

Overheating is why I finally gave up on laptops. Didn't matter how nice of a laptop I got, it always started having those problems in a year or two

[Dr. Ed 2]

I hate to say this, but the nicer one you got, the worse the heat issue was going to be. Faster chips (etc.) use more power...

There are external cooling pads that you can put under a laptop, they have their own fans and (preferably) their own power supply.

But laptops are increasingly disposable. 🙁

[Dan Schiavetta]

I did a webinar last month on Zoom. I didn’t know about the cropping.

At the beginning, explaining the changes in technology since I first became a lawyer, I picked up a 5-inch floppy drive. But due to cropping up to my shoulder, the participants couldn’t see it. What they saw was an old guy inviting them to look down at . . .

[Dr. Ed 2]

There used to be 9 inch ones.

I've actually seen a few. Not the machine they would run on...

[Dan Schiavetta]

Actually I said that too.

I said “here is a 5 inch floppy. In the old days it was 8 inches.” All the time, I was pointing down at something they couldn’t see.

[Commenter_XY]

Hilarious. 🙂