Tech Notes

Guesting on Mac Power Users

Last week I was lucky enough to be invited back to the Mac Power Users podcast for the third time (previous visits here and here). This time we focused heavily on video conferencing for obvious reasons, and I talked about some tips related to Zoom window management, making use of multiple screens, not to mention my troubles with virtual cameras.

Though perhaps it’s being released later than optimal in terms of utility to the readers of this blog, I do hope you give it a listen and share any thoughts in the Comments below or on the MPU forum.


MPU episode page | Apple Podcasts

Update: During the episode we talk about a image of my setup that I shared, but looks like it didn’t make it into the show notes. Here it is below:

Free Options for Sharing Handwritten Student Work

A recurrent problem during my statistics course last semester was that it was difficult for students to share handwritten work, diagrams, and drawings when I sent them into breakout rooms to work on a particular problem.

I’ve documented the various ways I use a tablet to handwrite in my courses on this website. The problem is, these methods presuppose the sharer owning a tablet, and often requires the use of paid software to make it work effectively. For students who need a free and easy way to share handwriting, this won’t work. Instead, I recommend using an app that lets you mirror your phone’s camera (with some additional features) via screensharing, to use it as a bespoke document camera:

  • Overviewer (iOS): This app relies on Zoom’s built-in iOS sharing function (either wirelessly or wired) to mirror a direct camera feed. It also gives you the option to rotate the orientation of your camera, something you can’t do with the built-in camera app. The developer produced the following video walking you through how to use it:
  • Vysor (Android): this is a desktop app (available on all platforms) that will mirror your Android phone’s screen onto a computer window, which you can then share using Zoom’s window sharing feature. It’s less elegant than Overviewer, but it seems to work. Here’s a video of Richard Byrne setting up and using it (full post here):

The final step is positioning your phone appropriately. While you can certainly buy a nice gooseneck phone holder, a stack of books will do as well (the developer of Overviewer addresses this here):

Putting a timer on your shoulder using an ATEM Mini

Update: Since writing this post Luke Stein pointed me to an app called H2R Graphics, which lets you overlay a timer on your computer if you have a setup like an ATEM Mini. It’s a little funny to set up – you plug your computer into the ATEM, and then back from the ATEM to the computer – but the result is a pretty flexible timer that’s quite useful!

While in meetings or teaching, it’s often useful to have a timer visible to everyone to help keep track of time. I was interested in having this overlaid atop my video and, using the Chroma key function of my ATEM Mini, I was able to do so.

The secret is creating a video or presentation of a countdown timer with some kind of green background. I did this by creating Keynote presentations with this AppleScript and then exporting them as movies. Lucky for you, I’ve posted a few sample timers here for two, five, and ten minutes.

Once I’ve created the timers, I just plug in my camera into one source of my ATEM Mini, and my iPad into a second source, and overlay them in the following way:

Pretty spiffy, and quite useful!

P.S. It’s easy to do this much more cheaply using OBS. Just right click on the video source in the list of Sources (it can be your iPad, or you can download one of the videos from above and use it as a Media Source), click “Filters,” click the plus sign under “Effect Filters” and select “Chroma Key,” and make sure the Key Color Type is set to Green. Voila!


The Promise and Peril of Virtual Cameras on Zoom

A problem and a potential solution

This post is the product of several months of experimenting, learning, conversing, and purchasing. It came from a desire to move away from traditional screen sharing, which is often characterized by your slides/visuals taking over a huge portion of your students’ screens (which can be offset somewhat with side-by-side mode).

One way of getting around this is to use what are called "virtual cameras" – in essence, using software or hardware to create a more sophisticated overlay of video/images/feeds, which then get treated by Zoom as a regular webcam. Using software tools like OBS or mmhmm, or hardware tools like the ATEM Mini, you can get some really fun and engaging visuals. Here are a few examples, starting with an excellent introduction by the always insightful and creative Luke Stein:

Once you have a virtual camera all set up, all you have to do is select it from Zoom’s list of cameras to start using it:

Theoretically, the use of virtual cameras should let you create rich, overlaid environments where students can see you and additional content through a single webcam, without having to futz with Zoom’s screen sharing interface (which can be clunky and slow in my experience).

It was with this promise that I embarked on dozens of hours of experimentation with all the software and hardware that I could find.

The problem is, at least with Zoom, this ends up not working very well.

The bad news

The reason for this is that Zoom is constantly making tradeoffs between quality (resolution) and smoothness (framerate) to optimize video, and in doing so is making a lot of assumptions about the nature of your video. In short, it assumes that you want your webcam to be smooth at the expense of quality (it’s weird to have choppy video of you talking) and your screen sharing to prioritize quality at the expense of smoothness (you’re often showing a static image with text on it, and that text must be readable).

Perhaps you can see the problem already – if you’re sharing your slides with you overlaid on top of them, you want your slides to be high quality and your video camera to be smooth. But since you’re just piping in a single virtual camera into Zoom, it’s treating your feed like a webcam – smooth and low quality, making it difficult to read text.

The worse news

This problem has gotten worse since COVID hit, since the huge pressure on Zoom’s infrastructure has led them to essentially disable the sharing of a webcam in HD regardless of your settings (accessed September 7, 2020):

Note: 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.

That means that your webcam will pretty much always be transmitted at 360p in any classroom setting.

The even worse news

The part that concerns me the most is that it’s difficult to test this on your own, since (a) On your computer, Zoom shows your local uncompressed video feed so it looks fine to you; and (b) The nature of its compression changes as more people join. What this means is you might end up getting comfortable a really cool virtual camera setup, starting a large Zoom class, and finding out that none of your students can make out what you’ve typed or written. That’s, like, teaching-stress-dream-level bad news.

A (kind of) workaround

One way to get around this issue is to use an option in Zoom’s Advanced Screen Sharing window called "Content from 2nd Camera":

Once you click this and then switch to the appropriate virtual camera, Zoom will start to transmit that camera in high resolution, prioritizing it like it would prioritize a regular screen share.

The problem is – you guessed it – doing so drastically reduces the frame rate that Zoom sends from that camera. You can try to offset this by clicking "Optimize Screen Share for Video Clip," but that ends up transmitting a quality that’s quite similar to what you’d get from just using the webcam itself. Here, you can see it switching between high resolution (1080p) low frame rate (vacillating between 20 and 2 fps) and low resolution (360p) high frame rate (30 fps):

A cry for help

My sincere hope is that this entire post will become out of date as soon as possible – Zoom will return to enabling full HD webcam output and we can go back to trying out lots of cool software and hardware solutions to bring engaging content to our students.

Until then, I hope this post is a warning to teachers jumping on the virtual camera train without adequately testing out its implications for their students.

Finally, if you have figured out some way around these constraints, please let me know in the comments! The saving grace of these frustrations has been encountering an innovative and passionate community focused on teaching effectively online. I’m hopeful that there’s something I haven’t thought of that will be shared – I’ll update this post accordingly if so!

Playing a Collaborative Playlist on Zoom

A slide that I shared with students before class starts (h/t to Kathy Pham for quarantine name prompt).

As I prepare for my course this Fall, I’m constantly worrying about how to create community. Reflecting on my teaching this past Spring and what worked, I found a low-hanging fruit in the form of playing music in the 10–15 minutes before class as people roll into Zoom. Something about this really seemed to help students get more comfortable and willing to unmute and share how they’re doing.

I took this one step further in the Spring by creating a playlist that students could themselves contribute to. It’s fun to see students recognize a song playing that they themselves added, and explain why they chose that particular song.

So, without further ado, here’s how to play music over Zoom, and how to create a collaborative playlist for students to add to.

Playing music over Zoom

Before getting into the collaborative aspect, let’s go over how to share audio over Zoom.

When sharing your screen over Zoom, there’s a checkbox on the bottom left of the screen that says “Share computer audio” – this makes it so that whatever audio your computer plays is also sent over Zoom.

But it isn’t optimal to just leave a slide up for the entire 15 minute period. Sharing your screen takes over much of your students’ screens and prevents them from being able to see each other and you in the time leading up to class start. Instead, you want to share only your computer’s audio over Zoom. You can do this by clicking on “Share Screen,” clicking the “Advanced” tab, and clicking “Music or Computer Sound Only”:

Now your students aren’t seeing your screen, but they are hearing your computer’s audio. You can then switch to Spotify or Apple Music and start playing music.

Important note: For some reason, music playing on my computer is played much louder on participants’ computers than it does on my own. I have no idea why this is, but what’s important is that you turn down the volume from within the Spotify/Apple Music app before you start playing:

This volume slider is different from your computer system audio – it’s within the app itself. Be sure to ask participants if they can hear your music and if it’s too loud once you start sharing.

Collaborative playlists

So now you have music playing in your class, which helps create levity and put the room at ease. But what about letting students themselves decide what music gets played?

One straightforward way to do this is to simply have students submit requests in the chat that you or a member of your teaching team can queue up. If, however, you want to create more of a “living playlist” that students contribute to over the course of the semester, I suggest using a Spotify Collaborative Playlist (I wish Apple Music had this feature, but alas it does not). Here’s how you can go about setting it up:

  1. If you haven’t already, create a Spotify account (free or otherwise).
  2. From the Spotify desktop app, create an empty playlist by clicking the “New Playlist” button and name it something specific to your course.
  3. The playlist will now show up on the sidebar of the desktop app. Right click the playlist name and click “Collaborative Playlist” – you’ll now see a little circle next to your playlist.
  4. Right click on the playlist name again, and this time click on “Share > Copy Playlist Link”
  5. You’ll now have the playlist link in your clipboard which you can share with your students. Instruct the students to go to the link, add the playlist to their libraries, and then add songs to the playlist. Note that they’ll need a Spotify account of their own to add to it.

And you’re done! As students add to the playlist, it will update for Spotify on your computer as well. Be sure to ask students to take credit if their songs get played in class!

Teaching from Home: Three Reflections After a Week of Teaching Online

Last week was my first full week of teaching online. Like virtually every other teacher in the world right now, I learned a lot about what works for my course and what does not. There were many realizations that I had about the logistics of my class: for example, I learned it takes much longer to do almost anything than it does in person, and also that I should delegate more responsibilities to my teaching team than I had originally planned.

But the biggest realizations have been in the realm of student engagement. Here are three high level takeaways from my first week which I’m taking into Week 2:

Reflection 1: There are many more ways for students to engage with the class online than in person.

When teaching residentially, the primary mode through which a student can interact with the class is verbal. They can raise their hand and ask a question or make a comment; they can talk to the students sitting next to them; or they can have discussions in small groups. Of course, some classes use other methods, but for the most part students speak to each other and to you.

When teaching online, in contrast, it feels like there isn’t really a “primary way” for a student to interact with the class. Here’s a brief list of modalities that students can use to engage:

  • Raising their hand physically or virtually. When the instructor calls on them, they unmute and speak.
  • Using “nonverbal feedback” to indicate understanding, mood, or preference the instructor.
  • Using Zoom’s chat function to leave a comment or question for (a) the whole class, (b) a peer, or (c) the instructor or other co-hosts.
  • Responding to a poll that the instructor activates. After voting, the poll results may be shared back to the students.
  • Working with one another in breakout rooms on a discrete task, and coming back together for a report out afterwards.
  • Typing into a collaborative document or presentation (e.g., a Google Doc or Slide) alongside their peers/the teaching team/the instructor.

Reading this list should make your heart beat a little bit faster, both out of excitement and anxiety. On one hand, teaching online makes it easy to get the kind of engagement that many residential instructors aspire to (I’ve seen some really nice uses of Google Docs in residential courses, but those examples are few and far between). Students can collaboratively generate content, make their feelings known without the pressure of raising their hand and speaking to the entire class, and seamlessly share insights or concerns with each other and with you.

On the other hand, each of these modalities has problems associated with it, and doing them all at once is a recipe for chaos. What if students flood your chat room with side conversations? What if you’re halfway through your lecture and you suddenly see that half the class is signaling “Go Faster” while the other half is signaling “Go Slower”? What if the process of calling on someone, having them unmute themselves, ask their question, then mute themselves again shaves off a few seconds of class time every time, to the point where you’re losing 5-10 minutes of class time just on microphone management?

Luckily, I’m finding that the issues of one method can be addressed by the strengths of another. In my class this week, I left the chat window open to everyone, and quickly found it to be a distraction for myself and a large number of my students. Instead, I’ve decided to generally restrict students to chatting with co-hosts (my teaching team) and relying on hand-raising/verbal communication. However, during discrete times in class – question times, or when I ask for a large number of examples of some concept – I can open the chat to everyone. Suddenly the chat becomes a rich source of information for me that would take way too long to solicit via verbal responses. In short, I find myself asking when a certain modality should be employed more often than I ask if it should be employed.

Reflection 2: Unlike residential teaching, students’ interaction with your course is mediated entirely through a single small rectangle on their laps.

While teaching online opens up a host of possibilities for students to engage, it’s also limited by a seemingly obvious problem. While students in residential classrooms can easily switch between looking at you, looking at slides/visuals, and looking at each other, when online they must do so through the porthole of their computer screen. This has a few implications:

  1. There are time and energy costs to moving between your shared screen, their notes, your video feed, their peers’ feeds, the chat, etc. The more switching they have to do, the higher the risk of fatigue and confusion.
  2. Inertia can easily kick in, resulting in students just watching your shared screen and not their notes, their peers, or you.
  3. Every tool that you use outside of the videoconference – Poll Everywhere, Google Docs, links to reference material – is subject to the two problems above, reducing its effectiveness.

With these issues in mind, I’ve had to make some adjustments to how I teach (again, these are things that are working for me, not necessarily prescriptions for you):

  • Whenever possible, use Zoom functions instead of third-party services: I love Poll Everywhere and the rich set of polling tools it provides. However, unless I’m asking for free-response questions from students, I’m using Zoom polls instead. Similarly, despite the many advantages of a dedicated chat service like Slack, I’m sticking with Zoom’s more rudimentary chat feature. In short, unless I have an important reason to do otherwise, I’m keeping things in Zoom for the sake of student sanity.
  • Reduce the amount of content students need to process: As I’ve written before, while teaching residentially I make use of a main screen (for the handout) and side screens (for supplementary slides/animations/polls). When switching to online, I was largely able to replicate this two screen setup in Zoom (though I needed a bunch of screens to do so). However, I quickly learned from students that having to view two simultaneously broadcasted screens on their computers while also taking notes was too challenging, even if the content was shared in high resolution. The problem wasn’t blurriness – it was cognitive load.
  • Mirror handouts directly: In my class, I provide students with a guided handout (with lots of empty space and questions), and then project a “slide-ified” version that I create which emphasizes certain parts of the handout and breaks up with the content. For the same reasons as my previous point, I’m now projecting exactly the same handout that the students have to make it easier to follow the class. I can still emphasize certain content by zooming in and out of sections as needed, but projecting the handout that they also have and writing on that appears to be a big help to students.

Reflection 3: As we transition to teaching from home, students are transitioning to learning from home.

As we scramble to successfully move our classes online, it’s easy to lose sight of the fact that our students are having to make significant cognitive, physical, and emotional changes themselves. For a moment, let’s put aside the obvious distress of COVID-19 and social distancing and think about the transition to online learning. Students who are taking 3 classes a day are now sitting in front of a videoconference for 4 or more hours, sometimes straight! That means not walking between classes, not chatting with peers, not going outside for a few minutes before class, and not talking with their instructors before or after class. Even without a global pandemic, this is a tough transition.

Here are a few small suggestions I’ve tried in order to be a positive force in my students’ lives during this time:

  • Commit to ending class on time, always. I put the most important one first. Transitioning to online has meant that I’m not always getting to the content that I planned to cover, and it feels like a disservice to not get to those topics when time has run out. But the fact that students don’t have to walk to their next class doesn’t mean that the transition time between classes isn’t important to them. In short, I want to make sure I respect the contract that I made with my students way back in January.
  • Build in stretch breaks. I aspire to give my students 30 seconds to stretch every 30 minutes. I find this much harder to do in practice given all the time constraints mentioned above, but this is a nice way to re-center the class when attention starts to drop.
  • Play music before class. I saved the best for last. When I started the Zoom conference on Thursday and shared my introductory slide, I also shared my computer’s sound and played some fun music while they waited. It was just wonderful to have students roll in looking tired and frazzled, perk up a bit because something was different, half smile as they realized there was music playing, then start to bob their head back and forth. By the time class actually started I even had a few students dancing in their seats! I’ve since made a collaborative playlist on Spotify and asked students to add to it for the remainder of the semester. It feels silly, but maybe silly is what we need a bit more of these days. [UPDATE: I wrote a quick post on the logistics of doing this]


I’m interested in returning to this post in a few weeks and seeing how much I’ve changed my approach, and how wrong some of this sounds in retrospect. I hope that’s the case – most of us are new to this, which means there’s so much room to grow.

Be physically and emotionally well. Let me know if you have thoughts in the comments.