Week of the 23/10/2023 - #43

More nice demos …



  • Flashparty 2023
  • Screen recording in Linux with ffmpeg
  • More cool demos
  • 4k Sound demo tool - Sointu


  • Cellular automata to generate sequences

Flashparty 2023

This weekend was the Flashparty 25th aniversary here in Buenos Aires, 🇦🇷. There were a lot of interesting things happening. He’s a summary of the things I enjoyed.

My favorite PETSCIIs

These are my favorite entries in the PETSCII compo.

Linking Ape

“Linking Ape” by TheRyk

El Pombero

“El Pombero” by Sande


“Astro” by Almighty God

R'lyeh Gross

“R’lyeh Gross” by Skleptold

La Pelota No se Mancha

“La Pelota No se Mancha” by Almighty God

Other nice imgaes

Rainbow in the Dark

“Rainbow in the Dark” by Slaxx / Excess. Winner of the oldskool pixel art compo.

Mod 7

Mod 7 screenshot

I wrote an entry for FP23 called “Mod 7”. It’s a 256 byte textmode MSDOS intro. It requires a Sound Blaster Pro and uses the OPL3 chip with 3 channels and two instruments. The music is synced with the (very simple) visuals. This has been tested in dosbox 0.74-3 and can be compiled with nasm version 2.16.x. The visuals are a version of the examples presented here:

Blog post on xor mod N

which come from this Twitter thread:

Twitter thread

The sourcecode is included in the ZIP and will soon add writeup in here.

Screen recording in Linux with ffmpeg

To record a video you set the video_size parameter to the width x height of the video you want to capture. Not sure how to offset so it records the current screen with offset 0,0.

ffmpeg -video_size 730x635 -framerate 25 -f x11grab -i :0.0+0+0 1.mp4

To crop the video later on you can use:

ffmpeg -i in.mp4 -filter:v "crop=720:544:0:89" out.mp4

where 720:544:0:89 are width:height:offset x:offset y.

More nice demos …

Amazing 4k demo

Nice JS demo - TRBL - Hallmackenreuther

Pouet / DemoZoo / YouTube ▶️

Xor demo

Geometric Linux demo - L’enveloppe

Screenshot of demo

Demozoo / Pouet / Shadertoy / YouTube ▶️

4k Sound demo tool - Sointu

Sointu screenshot

A cross-architecture and cross-platform modular software synthesizer for small intros, forked from 4klang. Targetable architectures include 386, amd64, and WebAssembly; targetable platforms include Windows, Mac, Linux (and related) + browser.

Cellular automata to generate sequences