This chapters aims to take a humorous and unusual approach to explain some fundamentals of how video encoding works. We aim to do this by entering the slightly crazy world of Datamoshing.

About Datamoshing

Datamoshing refers to a particular way of breaking video files so that they look strange. This is normally done for entertainment in videos like music videos.

The process of creating datamoshes involves some understanding of processes in video encoding including i-frames, p-frames and the concept of motion tracking.

Datamoshing step-by-step

The following videos show you how to do datamoshing and gives you the chance to try hands on manipulation of video files. So here's part 2

and part three

The how to video mentions 2 main bits of software. Avidemux and FFmpegX.

Avidemux is available for Mac, Linux and windows. There is a FLOSS Manual on it here.

But, If you are not using mac then you won't be able to use FFmpegX. However, there is a really easy way to achieve the same result using the command line application ffmpeg which will run on a Linux computer.

It is also a hand link to our next chapter which takes the use of ffmpeg much deeper. This is a good task to get you started.

To reduce / remove keyframes use the following command as an example

Code:

	ffmpeg -i infile.flv -g 500 outfile.avi

the -g option specifies keyframes. You will get an error if you set this too high try this with ffmpeg (999 is still very high but gives no fatal error). Your outputted files now have very few i-frames.

After this you can use avidemux you can append the second one and delete its i-frames by manouvring with the double-arrrows, setting in and out points and deleting them.

Assesment Task

The fun assesment task for this chapter is to either create a datamosh and post it to a video sharing site to share with us in the comments (please do!) - or to write a comment / blog post explaining your knowledge (boo!)