This project started when I wanted to create a short stop motion animation video or photo slideshow using some photos I had taken. There was not a great amount of motion in my photos and I did not want to create a very smooth series of animated motions, involving a very large number of individual frames. However, unlike a standard slideshow, I did want the individual images to be displayed for varying lengths of time to create a sense of movement at varying speeds in the animation. I also wanted to encode the resulting video in various formats for different purposes, ranging from displaying on a home computer or web page to a HD video for displaying on a large screen.

Since the animation I wanted to create was not very complicated and involved only a relatively small number of images, I started by looking at software for creating slideshows which allow for varying lengths of time each image is displayed. The first promising software I came across was Imagination, which is billed as a "lightweight and simple DVD slide show maker for Linux", which sounded just what I needed. Unfortunately, when I downloaded the source code and tried to compile it, I discovered it required an excessively new version of Gtk+2, which was newer than the version available on what was then the latest version of my Linux distribution, CentOS, so simply doing a 'yum update gtk+' just resulted in a message telling me I already had the most recent version installed. Being the lazy person that I am, I gave up at this point rather than trying to download the required version of Gtk+2 and installing it manually.

I next came across a stop motion animation software for Linux, Stopmotion. Although I succeeded in making a very short rudimentary test stop motion video, I found the software did not work as well as I had hoped. To cut a long story short, the version I built on my Linux distribution had some strange behaviours and lacked certain key functionalities, for reasons which I was again too lazy to investigate further in order to fix the problem. A more general criticism is that it only allows creation of frames by dropping individual images into a timeline (which I believe is typical of most stop motion softwares) - there is no way to automatically generate a large number of frames from the same image. This would be fine if there is a lot of motion and each individual image appears for only a fraction of a second. For my video (and for most slideshows in general), most images appear for over 1 second, and at 25fps, that means at least 25 frames per image. In fact, this is true to a large extent of most stop motion tutorials I've come across. They mostly assume that you are creating a stop motion animation in the "standard" way, where objects in a scene are moved in small incremental amounts and then photographed, and each shot corresponds to a single frame which is to be displayed for the same amount of time. However, if the images you shot are to be displayed for different lengths of time, or if the images were not shot in the same order as you want them to appear in the video (which is probably the case if you are creating a slideshow from a collection of images), then you need to come up with a way of generating the frames in the correct lexicographical order.


I noticed when trying to change the video encoding settings that Stopmotion was using either mencoder (which is part of the mplayer package) or ffmpeg to do the encoding, and it was simply allowing the user to edit the command line options to either mencoder or ffmpeg. At this point, I thought, if that was the case, I could just issue the mencoder/ffmpeg command directly from the Linux command line. This was how I ended up working out how to do the whole thing from the Linux command line, with the help of 3 short shell scripts that I've written, and without using any specialized software, other than mencoder or ffmpeg, which are included as standard with most Linux distributions.