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#+TITLE: Creating a High Quality GIF with Transparency
#+DATE: 2022-10-24T02:02:00-04:00
#+DRAFT: false
#+DESCRIPTION: My process for creating a high quality, optimized gif with transparency
#+TAGS[]: gimp, kdenlive, ffmeg, gif
#+KEYWORDS[]: gimp, kdenlive, ffmeg, gif
#+SLUG:
#+SUMMARY:
I spent quite a bit of time trying to figure out the process to create
the gif at the top of my [[{{< ref "how-bsd-authentication-works" >}}][How BSD Authentication Works]] blog post, so I
thought I'd share it.
Here's how to create a small, high quality gif with transparency using
a video and an image as source material.
I'd wanted to combine the image of puffy (the blowfish) and the
spinning gears to represent the OpenBSD internals.
Initially I went made several attempts using different software
like =ffmpeg=, =shotcut=, and =obs=, but none of them were able to
create what I was looking for.
This is the process that I ended up with that worked for me.
First I created the image I wanted for the overlay in GIMP. This was
the OpenBSD mascot with a cutout in the center. I then found a gif of
spinning gears. I opened the gif up in Kdenlive and used the colorize
filter to get them all yellow so it would fit in with the puffer fish
theme.
Then I imported the overlay image (Puffy with the cutout) and
placed it on top. I then rearranged and transformed things until it
was how I wanted.
From there I went to render the video in Kdenlive, and used the =Video
with Alpha > Alpha MOV= preset. I'd tried using the =webm= preset
first but =ffmpeg= seems to be more picky about that, plus this
=mov= is lossless so it's better for this purpose anyways.
I then took that video and split it up into frames using =ffmpeg=.
#+begin_src sh
mkdir movframes
ffmpeg -i bsd\ auth.mov movframes/auth%03d.png
#+end_src
I then opened the first frame in GIMP. From there I opened the
remaining frames as layers through =File > Open as Layers=, and
selected the remaining frames using shift click.
I then exported them as a =gif=, making sure to check =animated= in
the export menu, and set the time delay between frames.
The =gif= that's exported from GIMP was alright, but it wasn't very
optimized and the timing seems to not work correctly all the time
for some reason.
To fix this I used =gifsicle= to both optimize the gif and set the
framerate correctly.
#+begin_src sh
gifsicle -d 4 -O3 -o output.gif input.gif
#+end_src
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