How to record lectures with minimal after-edits

(author: Stefan Harmeling, created: 2020-09-02, license: CC BY-SA 4.0)

There does exist quite a bit of information about this topic at the HHU wiki, e.g.

• https://wiki.hhu.de/display/HHU/Bereitstellung+von+Lehrvideos+und+Veranstaltungsaufzeichnungen
• https://wiki.hhu.de/pages/viewpage.action?pageId=160268766
• https://wiki.hhu.de/pages/viewpage.action?pageId=160268775

In particular, the colleagues from the Multimediazentrum (MMZ@HHU) are really helpful with many questions I had.

Here are simple setups that I use to record my lectures with a Mac.

TLDR / useful software

• Camtasia (to record screen and mic)
• Display Menu (to reduce the screen resolution to non-retina)
• Quicktime Player (to show handwriting on an ipad)
• Paper (on ipad for handwriting)
• Visualizer (for showing the webcam in a window)
• Apptivate (to switch between programs with function keys)
• Horo (to show a stopwatch in the menubar)

Simplest setup / more details

Hardware: a laptop with builtin microphone (I use a 2014 Macbook Pro)

Software: Camtasia

Steps:

1. start Camtasia to record the screen and the microphone, it let's you select what to record, just choose screen and mic.
2. give the lecture using Powerpoint, Keynote, Preview (PDF), ...
3. stop Camtasia recording by clicking on some menubar item that looks like two frames of a film
4. in Camtasia export the video with "Share" --> "Local File", set parameters: "Export to MP4", click on "Options", under Video (as suggested by MMZ@HHU):
   • Framerate 25
   • Data Rate: 1000 kbits/sec
   • Keyframe Rate 30
5. get a tea while exporting takes place (can take 30 minutes)
6. upload video to the mediathek

Reduce screen resolution (don't record retina resolution!)

Problem: assuming a Retina display on the Mac, the display might tell you that the resolution is 1280x800, but actually it is recording 2560x1600 since it is "retina". So the file of the video is very large, possibly the quality is also not great or the sync between audio and video is broken, because your computer is quite busy writing out the high resolution to disk.

Solution: use the App "Display Menu.app" to reduce the resolution. E.g. on my laptop there are in that application two options with 1280x800 one with a white-background "16:9" icon, one with a dark one. Choose the dark one (as explained in its documentation)! In Camtasia's recording dialog you should see the "real" numbers of the resolution you are about the record. So try this with Retina, you see 2560x1600 in Camtasia's dialog, using "Display Menu" you can reduce it to 1280x800. There might be other apps that can correctly set the resolution to non-retina. The builtin preference panel "Displays" sometimes can do it (try clicking on it with 'option' key), mine can not.

Chop out only 1280x720 (i.e. omit top 80 pixels)

Problem: you are also recording (if not in fullscreen mode) the menubar on the top of the screen or for other reasons you want to use some "standard" image format.

Solution: choose "720p HD (1280x720)" from "Preset region" in Camtasia's recording dialog. Then move the appearing rectangle to the bottom part of your screen and leave a margin on top. "720p HD" is also a good format for uploading to the mediathek website (so less editing required afterwards).

Note: also presenting in fullscreen removes the menubar, but the chop-out-setup has the added value, that you can show during the lecture other information (e.g. a website or your text editor for live programming or a youtube video) and everything will be recorded by Camtasia.

Tip: timer in the menu bar

Problem: after the recording you would like to get rid of some passages of your video, but how can you quickly find the exact locations afterwards in the editor of Camtasia?

Solution: let a timer/stopwatch (with seconds) run in the menubar (e.g. Horo.app works well, or put a stopwatch on your table). If you want to redo something during the recording (for home made lectures), write down the time of the timer on a sheet of paper and redo the passage until you are happy with it. After finishing the whole lecture (in one big recording) cut out the failed parts using the Camtasia editor. For this go backwards through your paper list of times and backwards in time through the video. You find the position immediately using the time stamps.

Include handwriting into your recording

Problem: how can I show and record handwriting?

Solution: connect an iPad to your Mac with a cable. Then start the application "QuickTime Player" and choose "File"-->"New Movie Recording" from the menu. A window opens with a red recording button in the middle of the lower part. Right next to that button is a down arrow, looking like a "v". Click on it and choose "ipad". Now the window should show everything you are doing on the ipad. Now if during your Powerpoint presentation you want to show some handwriting (e.g. deriving P=NP for N=1), just switch to the "Quicktime Player" application and start writing. After that just switch back to your presentation. Camtasia will record everything it sees on the screen, so also your handwriting will be recorded.

Note: what app for writing? I like "Paper", since it is just a white sheet of paper without any menu (if you set it up properly).

Note: to quickly switch between apps during your lecture, assign your function keys to directly switch to a particular application (e.g. using the tool "Apptivate", there might be other ways to do that).

Note: why not use "QuickTime Player" instead of "Camtasia" for screen recording? The problem with "Quicktime Player" is that its recording files are much bigger than those of "Camtasia".

Include a video of yourself (for home made lecture videos)

Problem: how can I also show a video of myself without much editing?

Solution: of course Camtasia can also record your webcam in addition to the screen in separate tracks. However, you would have to do some editing afterwards to show it in the corner of the final video. There is a simpler solution. Just start a program that shows the video of the webcam in some window and position it on your screen. For this to work nicely, your presentation program should also run the presentation in a window. Preview (PDF) can do this. Also Powerpoint can do that (from the menu "Slide Show"-->"Set Up Show..." choose "browsed by an individual (window)"). Since version 10 also Keynote can do that: menu "Play" --> "Play Slideshow in Window".

Note: what program to use to the video of the webcam? I use "Visualizer" from IPEVO (however, lately it was showing ads, if you don't own an IPEVO, not sure whether they removed that "bug"). If you are familiar with the commandline and python/opencv you could also use a little script that Tobias Uelwer and I wrote for this purpose. It allows you to also choose the aspect ratio, crop and mirror the image, make it grayscale. The script is called webcam-sh.py and is included in this repository. Start it with python webcam-sh.py or with parameters, e.g.

python webcam-sh.py -p 0 223 -s 0.302500 -c 300 0 680 720

works for me. While running you can use some hotkeys (see code) to change settings. After quitting (q) it will show you how to call it next time to get the settings immediately.

Include a video of yourself (during lectures in classrooms)

Problem: can I use the trick to show the webcam output on the screen (instead of editing it into the video afterwards) in classroom?

Solution: get an external camera for this purpose! I use an IPEVO V4K USB document camera with a 5 meter USB extension cable (this is at the limit of USB, try a shorter one if it is not working). The camera is placed in the front or second row and then just show the video of that camera on the screen to include it in your lecture video.

Note: the only problem with this setup is that also the beamer will project the video of yourselves, but it almost eliminates the video editing afterwards.

Externals microphones?

Problem: sound from the internal microphone might not be great, especially when you walk around in a classroom

Solution: get a better microphone! I use a Rode NT-USB-mini for home made lectures (and video conferences), but there are many alternatives. After plugging it in you can select it in Camtasia's recording dialog and check the level. For classroom I use a "Sennheiser XSW2-ME2 E", which is a wireless lavalier microphone with a (non-battery) receiver that is then connected with a "LINE 2 USB Behringer" cable that connects directly to the USB of the laptop.

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