2015-07-04

Kdenlive for Fun ... and Profit

So far I've worked with Kdenlive only on my hobby projects. But lately I could put my experience gained at home to good use at my day job. To better and simpler explain a research project me and my colleagues are working on I decided to go for a short video instead of the usual slide presentation.

The Power of Moving Image


To put it mildly: the absolutely positive feedback to our ten-minute video blew us away. People repeatedly reported back that now they do understand what we are about and commended us on both idea and video being well done. Before, we noticed that many people had difficulties imaging that our ideas do work. Well, talk about the power of imagination when it comes to moving images...

So, many thanks to the Kdenlive developers for their tool that helped shaping my ideas into presentation.

Lessons Learnt: Test Early, Test Often


Of course, we early decided on not to go for the often-seen (and often terrible) screencast video format. We knew that this had to be right on spot at first attempt.

It turned out to be a good idea that we first did a rough cut of only one section in order to see how things work and how test viewers react. Our two or three test viewers gave us valuable feedback to improve on this first section. Only when we and our testers were satisfied we edited the remaining sections in the same way as our prototype section. With only a single section done yet, early adjustments were easy, and later changes would have result in a lot of boring repetitive adjustments. Better avoid this early.

Our video consists of some live screen footage, as well as still illustrations, and speaker takes in between. There is voice over the stills and screen footage to explain what is seen so the audience will understand what is going on. Additional titling both in-screen as well as between sections provides visual guidance and enforces key sentences ... without getting scholarly.

External Titling with Inkscape


For the first time I did the extensive titling I needed in Inkscape instead of Kdenlive. This allowed me for much better typographic control ... that I needed since I tried to avoid any distracting graphics ado. Fortunately, Kdenlive could digest my SVG titling, albeit I had to simplify multi-line text into single-line text, otherwise Kdenlive would not render text correctly.

The only other graphical trick I'm using is an unobtrusive throbber nevertheless clearly indicating scenes where I'm speeding up simulator results that would otherwise take around a minute. This way I'm demonstrating that these things are properly happening in the simulator without my audience watching paint dry. The throbber actually is again a simple still SVG image. Using Kdenlive's keyframe-able transitions I'm animating the throbber by slowly rotating it once from -180° to 180° between two keyframes, then adding the next keyframe to -180° again if the throbber needs to rotate further on. So using only the Kdenlive built-in effects and transitions I was able to reach my goal.