Festering Ideas #

Epilepsy warning

I’ve always liked glitchy looking images and videos. I just never bothered creating my own. That is until I came across the frei0r library by the Dyne project. Here I found the glitch0r effect and messed around with it for a bit in Kdenlive. However, as a terminal terminal user, using a graphical interface didn’t feel right. So I figured out how to use the frei0r effects with ffmpeg.¹ Now I could script the butchering of a bunch of files at once!

Among the effects in frei0r, I also found scanline0r and a bunch of other effect, but wasn’t quite happy with the fact that the scanlines in question seem to be stuck at one resolution. Some time later (a few years), I heard someone complain about professional footage being interlaced and it looking like shit as a result. Upon closer inspection it had been the kind of ugly mess I’d been hoping to create with the scanline0r filter. So I got around to figure out how to interlace video using ffmpeg and butchered some videos further.

First Manifestations #

Here’s a demonstration of what I managed to do so far using Big Buck Bunny as an example:

This snippet was chopped up using ffmpeg using the following command:

ffmpeg -ss 00:01:17 -i big_buck_bunny_720p_h264.mov -to 00:00:11.75 rabbit_original.mp4

ffmpeg -ss 00:01:17 -i big_buck_bunny_720p_h264.mov -vf 'frei0r=filter_name=glitch0r:filter_params=0.05|0.8|.02|1,rgbashift=rh=6:bh=-4,interlace=scan=tff:lowpass=complex,format=yuva420p' -to 00:00:11.75 rabbit_mangled.mp4

The full original video can be found on the Big Buck Bunny website

Magick #

In the mean time, I had been messing around with imagemagick as well. Using it to create pictures of words of phrases when I felt like it. Usually I would use something like the following to that end:

magick -font $(magick -list font | grep Font: | awk '{print $2}' | fzf) -pointsize 288 -fill white -stroke black -strokewidth 5 -background transparent label:"*Insert text here*" example.png

Black Magick #

So the other day, I thought it would be interesting to see if I could make some text using imagemagick and then feed it to ffmpeg to create a gif with an interesting glitch effect.

Initial text #

Some text made with imagemagick because its the easiest way I know to create a simple image with text.

magick -font Iosevka -pointsize 300 -fill cyan -background transparent label:"Glitch" glitch.png

Note: The pointsize here is relevant as ffmpeg will complain if the image has a pixel count not divisible by 2. 300 works with Iosevka, if it doesn’t work with your font of choice, try a few sizes until you find one that does.

With glitch0r #

ffmpeg -loop 1 -i glitch.png -vf 'frei0r=filter_name=glitch0r:filter_params=0.05|0.8|.02|1' -t 10 glitch.gif

Mangled results with imagemagick #

Initial results looked quite interesting. Then I thought it’d be funny to convert this gif to an apng – animated png. This resulted in the gif being butchered in a really interesting way due to something in imagemagick being broken; when converting the gif to an apng using ffmpeg, it will come out on the other end in a state you’d expect.

Epilepsy warning

magick glitch.gif APNG:glitch_animated.png

Note: You have to supply the fileformat in prefix form as apng isn’t the standard format for the ‘png’ file extension.

After creating the apng I decided to convert it back to a gif in order to save some space as the apng was 11M.

magick APNG:glitch_animated.png glitch_butchered.gif

I experimented a bit with both ffmpeg and imagemagick to see what the best results would be. ffmpeg is significantly faster with the default settings but has a slightly large filesize.

$ ls -lh glitch_*
-rw------- 1 yog-sothoth users  11M Sep 26 18:57 glitch_animated.png
-rw-r--r-- 1 yog-sothoth users 5,1M Sep 27 09:48 glitch_ffmpeg.gif
-rw-r--r-- 1 yog-sothoth users 4,2M Sep 27 09:49 glitch_magick.gif

Note: No, I have no idea why the apng has a umask of 077. Imagemagick just spat it out like that.

Conclusion #

I hadn’t seen anyone butcher visuals quite like this before, so I thought I’d write a post about it with the idea that someone else might find it interesting.

So, go out there and butcher some visuals!