W:Capturing a lecture

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Capturing a lecture


2007-12-18 , Capturing a lecture, Capturing a mathematics lecture, Manual Audio and Slide Capture, Automated Audio and Slide Capture, OpenOffice Slide Capture, Lecture browsing system.

1 Capturing a lecture

When thinking about 'recording' a lecture, most people think about video in the first instance. However, video, especially for a live event (that starts and progresses disregardless of technical difficulties), is difficult to do. In my experience, most people who set out to do video a lecture (particularly as their first video project) never complete the project. So the first thing to consider is whether you need video. Capturing a lecture does not mean videoing it.

Think whether you can just do audio. Really an audio recording is the baseline, and you should get the audio right before thinking about anything else.

Even if there is a powerpoint presentation, an audio and pdf might do. What about the synchronisation between the powerpoint and the audio? Of course this is nice. But: It's more work (and might mean you don't get the project finished ever!), and it also means that you'll have less compatible output formats. So in any case, you should do audio and pdf, and offer a synchronised version ontop of this.

By even if there is a powepoint, and the lecture is strongly based around a ppt file (or other digital materials), it does not mean video. If you really want to synchronise the presentation, then don't think about video, but you're better off thinking about screen capture first.

You must think about release forms and copyright, see below.

2 The one where somebody stands up and talks

... and they don't have a ppt presentation, or experiments to show.

Don't bother with video, but do a good job on the audio (see Audio Recording Tutorial). Most people will simply fetch the mp3 anyway, and you might make a lot of effort preparing video, when not many people will watch it.

Take some nice pictures and put them onto your website alongside the audio recording.

It's often best to rely on your own audio, rather than trying to get audio from the venue sound system: Give the speaker a radio mic, see Audio Recording Tutorial

If the lecture is high profile, and you do want video, you'll need two cameras, so that you can cut between them. If you don't have two cameras, or don't know about video editing, either get help (from a trained professional :-) or go for an audio recording.

Really, start with audio.

3 The one where the lecture is based on ppt, and has not experiments, people on stage ...

First case: Suppose the lecture has a basic powerpoint, without tricky scientific content. I'd recommend to not bother with video. Do an audio recording instead (Audio Recording Tutorial), and publish the ppt as a pdf file alongside it. If this is your first experiment in capturing a lecture, focus on getting good audio!

Most people will simply fetch the mp3 to listen to offline, and you can stick the pdf into the same podcast feed.

Second case: "But I insist on synchronising the powerpoint, and put the result online." There are different ways to proceed:

  • You can use camtasia to do a screen recording. Useful particularly if there are lots of animations.
  • If the presentation isn't too complicated, and your recorder has a track mark button (like the Fostex FR2LE) you can use the trackmark button to mark slide transitions. Or you could use a stills camera, and use the timecodes from the stills camera to synch slides. Both these methods require discipline, otherwise you'll take a long time in the post processing. Details on Manual Audio and Slide Capture.

You'll still need good audio, ideally into a separate recorder, but you could also record into the laptop directly.

Only if this is sorted, think about video.

4 The one where the lecture has got no powerpoint, but lots of non-digital materials, and visual quality is less of a worry

You can go with one camera, but the result won't look too professional as you'll need to zoom about. More thoughts on Capturing a mathematics lecture.

Make sure you get good audio: Good audio is more important than video, see Audio Recording Tutorial

5 Two sources make good video

If you do want to video record a lecture properly, and to edit it together effectively, you will need

  • good audio, see above
  • two sources of video, so that you can cut between the two sources

5.1 A ppt and some non-digital materials - camtasia (or similar) + camera

If there's a ppt presentation, you should run camtasia (or similar) on the laptop to capture the presentation, which would give you a 3rd angle (and is *much*much* easier than trying to edit the presentation as stills into the presentation later, trust me on this one). Best to plug any old crappy mic into the laptop too, so that you have sound on camtasia to sync. If you don't have a mic on the laptop, point the camera at the laptop when you switch on camtasia so that you can sync that way. Camtasia has 30 day fully functional free trial so you can try the whole thing out.

Capturing ppt + just one camera can work well if you know what you're doing.


For more background on camtasia and other products, see Automated Audio and Slide Capture.

5.2 Two cameras (no ppt)

If there is no ppt, you'll need two cameras to cut between them. It is best to assign roles:

If you have two cameras, one of them stays on lecturer throughout, while the other camera gets closeups of experiments etc. If you don't preassign roles for the two cameras, then the edit becomes nearly impossible. (You also decide on roles during the intro of the lecture, and during the vote of thanks at the end: Basically one camera on the speaker throughout, and the other camera does the rest.)

Get sound on both cams so that you can sync. Run cams in LP mode to get 90 mins per tape, to have some safety margin. If possible, white balance both cams to the same target.

5.3 Two cameras + ppt

As above, capture ppt on camtasia. Assign roles for both cameras: Now that you have three sources, your edit will become much more complicated: Bear in mind that editing this will at least take about 10 hours, so you need to find yourself an editor who can commit this time, or set some time aside.

However, for most things two sources is the sweet spot for this way of production. Two cameras + ptt will take much longer to edit than two sources.

If your lecture is an outreach lecture, with lots of people interacting on stage, etc, you might need two cameras. If you really do have an all-singing all-dancing lecture, consider getting professional help :-), see Multi-camera production

6 Package your production

You might consider getting a few packaging shots from around the Cavendish for a title sequence.

If you have time you might consider doing a short interview with the speaker in a scenic location somewhere. That can work well as an alternative to a longer lecture. In fact, you might want to consider whether you are better off with the interview, rather than with capturing the lecture!

7 Release forms + copyright

Whatever you record will be completely worthless if you don't have release forms of speakers and participants. So:

  • Get the speaker to sign a release form.
  • If there are participants in the lecture (on stage), get release forms also. (Write on the release forms what the people are doing during the lecture, e.g. "help with gravitation experiment", so that the person assessing the legalities can judge whether you have got enough release forms.) Where kids are on stage, their parents need to sign.

Likewise, if there is 3rd party copyrighted content in the lecture (e.g. music of CD, DVD extracts, pictures in the ppt), you will not be able to use those parts of the lecture. If you can work with the lecturer, remove such content in advance. If you can't do this, you'll have to edit around it, or remove those bits of the lecture. Forget trying to clear the content: This is very expensive and extremely time consuming.

8 I'm done with videoing the lecture - what's next?

If you have to do editing for two or more cameras, be prepared for this to take time. Even if you've edited video before, it will take you about 10 hours to edit one hours worth of video. Using multi-camera features in the your editing application can help speed things up.

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