How to sync slides with audio/video, a few alternatives

June 8, 2010, [MD]

I really enjoy giving presentations and talks. They are a great way for me to think through my ideas, and systematize them, and I can trace some of my ideas now through a series of talk as they were gradually developed (with help from the audience). I try to be an interesting and engaging speaker (although I can always improve), and I usually spend quite a lot of time thinking through what I want to say, designing the slides, etc.

Ever since I gave my first public talk at Indian Institute of Public Administration, I've recorded my talks. Usually just using Audacity on my MacBook, with the built in microphone. Sometimes the talks have also been video-recorded, or there are even fancy systems that try to capture the slides and video together (although these systems are often fickle, and can fail completely). I began putting my slides on SlideShare early on, and have really enjoyed the exposure that website has given me. (All my presentations on SlideShare).

SlideShare offers one very neat feature called SlideCasting. You can upload or link to an MP3 of the talk, and use a syncing tool to have slides automatically progress at the right time during your talk. In that way, someone visiting the site can simply press play, and listen to the talk, with the slides advancing at the right time. Or they can jump straight to a certain slide, and hear what I said about that slide. It's a great concept, and most of my presentations use this feature. I try to not overload my slides with text, so if you just see them without hearing what I said, the presentation looses much of its value.

There are some issues with the SlideCasting feature however. It takes a lot of time to edit a one hour presentation, with maybe 150 slides. It's also very difficult to put slides close together, so if you rapidly progress through a set of slides (less than 5 seconds on each), it becomes difficult. I've also had some issues where I lost all the timings, or the timings came out of sync.

I wish SlideShare let me download a text file containing all the timings for a presentation I uploaded. Or import a file in the same format. This would have several benefits. Firstly, I would feel much safer that I can get my data out (I spend a lot of time creating timings, but if SlideShare ever goes under, or I want to move to another hosting site, I loose the timings. If I have the file, there is no guarantee that the other site will accept them, but it's at least a possibility). It's also a backup in case the timings disappear. And finally, it opens for creating tools that would for example record all my timings when I give my presentation, so that I could directly import these and save a lot of time.

I was just preparing my latest presentation, when I ran into a lot of problems. First, it turned out that the MP3 hadn't uploaded completely, it ended five minutes before it should. I only realized this after I had created timings for the whole file. After e-mailing support, they told me there was no way of preserving the timings, if I reuploaded the file! So I lost all that work. Then I did it all again, but somehow when I view it, the timings seem to all be out of sync.

So being quite fed up, I decided to investigate some other options. Omnisio looked promising, but it has been bought by Google to be integrated with YouTube, and does not allow new sign-ups (but we might see an interesting addition to YouTube once Google has finished "digesting" them). Finally, I decided to turn it into a video. I had a video of my entire talk, so I positioned that player on my screen, and the PDF of my presentation slides in a small Preview window right next to the video. I then used ScreenFlow to record the screen, and the system audio. I simply played the entire video, and manually advanced the slides at the appropriate time.

This process has some advantages. It's actually faster than creating the timings with SlideShare's tool - it only takes the amount of time it takes to watch the entire presentation. It's also much easier to have very rapid slide advancement, and it also preserves transitions (which SlideShare doesn't), although I rarely use those.

After recording the whole thing (I had to do it in two sections, and splice together, because I got a warning message about two little space left on the HD in the middle), I cropped it in ScreenFlow to only display the two boxes (video and slides), and exported it to a QuickTime file. This took quite a bit (and don't try to turn on multi-pass, it will take all night). I uploaded the finished file to Vimeo, and voilà. (See finished presentation on Vimeo).

Although the editing was a bit faster, the post-editing, rendering, and uploading to Vimeo took longer. It's also far from as elegant, since people cannot easily download the slides, copy and paste from slides, click on links in slides, or search on the content (SlideShare exposes the content as text, to make it Googleable). So still not ideal, but it was a fun experiment that worked fairly well. (It's surprising how often screencasting comes in handy for grabbing a piece of video that's streaming in a weird format, I also used it to grab some of the pieces I used in my Open Education around the world medley).


Stian Håklev June 8, 2010 Toronto, Canada
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