Distortions post

src/content/rambles/distortions.md

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+---
+title: "Distortions"
+date: "2024-09-26T17:14:09+02:00"
+author: "$HUMANOID"
+tags: ["ffmpeg", "imagemagick"]
+description: I've been messing around with various tools to create some rather nasty looking and sounding things.
+---
+
+# Festering Ideas
+
+{{< start-details summary="Epilepsy warning" >}}
+{{< img src="/images/distortions/butchered.gif" alt="A gif with flickering text saying 'butchered'" >}}
+{{< end-details >}}
+
+I've always liked glitchy looking images and videos. I just never bothered
+creating my own. That is until I came across the
+[`frei0r`](https://dyne.org/software/frei0r/) library by the
+[Dyne](https://dyne.org) 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:
+
+{{< video src="/videos/distortions/rabbit_original.mp4" type="video/mp4" width="500"
+caption="Original clip from Big Buck Bunny">}}
+
+This snippet was chopped up using `ffmpeg` using the following command:
+```sh
+ffmpeg -ss 00:01:17 -i big_buck_bunny_720p_h264.mov -to 00:00:11.75 rabbit_original.mp4
+```
+
+{{< start-details summary="Epilepsy warning" >}}
+
+{{< video src="/videos/distortions/rabbit_mangled.mp4" type="video/mp4" width="500" caption="My butchered version">}}
+
+{{< end-details >}}
+
+```sh
+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' -to 00:00:11.75 rabbit_mangled.mp4
+```
+The full original video can be found on [the Big Buck Bunny website](https://peach.blender.org/)
+
+# 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:
+```sh
+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
+```
+{{< img src="/images/distortions/example.png" caption="The font used is Iosevka" alt="Here I used the Iosevka font to create an image with the text *Insert text here*">}}
+
+# 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.
+
+```sh
+magick -font Iosevka -pointsize 300 -fill cyan -background transparent label:"Glitch" glitch.png
+```
+{{< img src="/images/distortions/glitch.png" alt="An image with cyan text saying 'Glitch'" >}}
+
+> *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 and some
+
+```sh
+ffmpeg -loop 1 -i glitch.png -vf 'frei0r=filter_name=glitch0r:filter_params=0.05|0.8|.02|1' -t 10 glitch.gif
+```
+{{< img src="/images/distortions/glitch.gif" caption="" alt="The same image as above but with generated/artificial interference using the glitch0r effect from the frei0r library" >}}
+
+### 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.
+
+{{< start-details summary="Epilepsy warning" >}}
+{{< img src="/images/distortions/glitch_butchered.gif" alt="A variant of the same image as before, but horrible broken due to the aforementioned bug in imagemagick" >}}
+{{< end-details >}}
+
+```sh
+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.
+
+```sh
+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.
+
+```sh
+$ 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!
+
+[^1]: For many of the frei0r effects I used Kdenlive to figure out their parameters.
+      And for a list of available filters, I checked the `ffmpeg-filters(1)` manpage and
+      looked for `frei0r`. Under the `filter_name` section, there are a few paths
+      listed where ffmpeg checks for `frei0r` filters.

src/themes

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-Subproject commit 53560c95d3bd33362e5552cb9efeaf8234724868
+Subproject commit 11b7a363dd47bfa418c97b82aa3d7a9951e9eb1c