This is a collection of custom script modules I wrote for use with RetroPie.
These are considered experimental at best, so use at your own risk.

• gnash - Open-source Adobe Flash SWF file player.
• lr-81 - Sinclair ZX80/ZX801 libretro core
• lr-np2kai - PC-98 libretro core
• lr-pokemini - Pokemon Mini libretro core
• lr-simcoupe - MGT SAM Coupe libretro core

Connect to RetroPie via SSH and run these commands in order:

cd ~/RetroPie-Setup/
git clone https://gitlab.com/SuperFromND/retropie-custom-scripts.git
sudo cp -R retropie-custom-scripts/scriptmodules/* ~/RetroPie-Setup/scriptmodules
rm -rf ~/RetroPie-Setup/retropie-custom-scripts

Alternatively, click the floppy disk to download a .zip of the scripts to install manually:

Below is a batch script that can convert an MP4 file into a GIF with minimal hassle.
The main benefit over EZGif is that this allows for 50fps gifs with no length limit.
Save it to a file, then place it into the same directory as ffmpeg.exe.

@echo off
set /P id=Drag your MP4 into this window and press Enter.
set /P size=What scale do you want this at?
ffmpeg -v warning -i %id% -vf "fps=50,scale=%size%,palettegen" -y palette.png
ffmpeg -v warning -i %id% -i palette.png -lavfi "fps=50,scale=%size%:-1:flags=lanczos [x]; [x][1:v] paletteuse" -y output/output.gif
start output

Windows's command line can process all files in your current directory at once.
The syntax is:

for %f in (*.extension) do command

Here's an example that uses ImageMagick to replace a specific color (formatted in RGB) with transparent. Very useful for things like ripping old game animations.

for %f in (*.png) do magick convert %f -transparent "rgb(19,19,19)" %f

Another example, this one uses FFMPEG and can convert folders worth of WAV files to OGG Vorbis. Handy, but be careful when using it!

@ECHO OFF

for /d %%d in (./*) do (
    echo Navigating to %%d
    cd %%d
    for %%f in (*.wav) do (ffmpeg -i "%%f" "%%~nf.ogg")
    cd ..
)

echo Done!

This command here can take an audio file and a PNG file, and using those, create a video file out of them similar to what you might find on YouTube channels that upload music.

ffmpeg -loop 1 -i image.png -i audio.ogg -c:v libx264 -tune stillimage -c:a aac -b:a 192k -pix_fmt yuv420p -shortest out.mp4