This posting tells the story how I got a video made of my old computer demo from almost 25 years ago. The story of that computer demo told in Computer Demo: Bogus Party III Video by Bogus Device posting.
That old program was designed to run on DOS operating system on a pretty old hardware. If I can make it to run nicely, I can make video of it: If it can be viewed on screen and audio can be heard correctly, there is always a way to record it – software, video signal recording hardware or as last resort a smart phone camera pointing to monitor!
The software was originally specified to run nicely in fast 386 and 486 computers (too slow in 386SX). The software supports Gravis Ultrasound soundcard (GUS) but works without it also (no sound without GUS). I wanted to save the whole presentation with both audio and video, but I was lacking a suitable old PC and Gravis Ultrasound (GUS) sound card.
So the way to try would be emulation as modern PCs should be powerful enough to emulate 25 years old PC hardware using software. DOSBox is free open source software that emulates an Intel x86 PC, complete with sound, graphics, mouse, joystick, modem, etc., necessary for running many old MS-DOS games that simply cannot be run on modern PCs and operating systems. However, it is not restricted to running only games. And is claims to have support for GUS emulation. This looks promising. A good thing that DOSBox is a full CPU emulator, capable of running DOS programs that require the CPU to be in real mode or protected mode as this demo was coded using that 32 bit processor mode. It can be used without owning a license to any real DOS operating system.
I also downloaded the “Bogus Party” software and saved the demo to
Now starting the DOSBox. I got two windows - a status window (can be ignored) and the main DOSBox window. Running the following commands on DOSbox window should make things work:
mount C C:/OLDGAMES
Mount command was needed before you running the software, to make my hard disk directory to be accessible from DOSbox environment. DOSBox’s environment drive naming is separate from computer’s file system. Here are some DOSbox tutorial videos:
Better DOSBox Video Tutorial – Download, Install, Configure, Setup, for use in DOS Games
DOSBox Tutorial (How to run games)
I got things partially working:
DOSBox runs the video ☺
but no sound yet
Maybe need to do some more tricks to get sound working.
I asked for some tips on Demoscene Facebook group. I got tip:
For GUS it doesn’t work out of the box, you’ll need to configure it and download some files.
Yes. I need GUS files, but the download links on DOSBox wiki did not work.
Ben I already tried “HuggyBaby’s Ready-To-Use DOSBox Ultrasound Folders” but it were no longer available
Maybe have to try install disk download next… but it did not work either. I got tip to try 86box as it should support gravis ultrasound.
Then I got tip to check out the following discussion to get DOSbod GUS emulation to work:
The files you need are attached to the first post in that thread.
Those instructions worked. When I got access to the sound card files and edited DOSbox conguration file with the following GUS config, things started to work nicely:
# gus: Enable the Gravis Ultrasound emulation.
# gusrate: Sample rate of Ultrasound emulation.
# Possible values: 22050, 44100, 48000, 32000, 16000, 11025, 8000, 49716.
# gusbase: The IO base address of the Gravis Ultrasound.
# Possible values: 240, 220, 260, 280, 2a0, 2c0, 2e0, 300.
# gusirq: The IRQ number of the Gravis Ultrasound.
# Possible values: 5, 3, 7, 9, 10, 11, 12.
# gusdma: The DMA channel of the Gravis Ultrasound.
# Possible values: 3, 0, 1, 5, 6, 7.
# ultradir: Path to Ultrasound directory. In this directory
# there should be a MIDI directory that contains
# the patch files for GUS playback. Patch sets used
# with Timidity should work fine.
Now DOSBox runs my computer demo with sound.
I am not sure if it will help to record. For recording I got the following tip:
DOSbox can record audio and video .. press Ctrl-alt-f5.
Unfortunately that DOSbox recording tip did not work for me. I for a video file. But when I tried to play it with all the video players I had, the result was file with sound but black picture. I am not sure if that was result of some strange video mode tricks that the demo used to speed up video updating faster, or some video codec issue on recording/playback. Lager I found out that according to Wikipedia the DOSBox The video is compressed using the lossless Zip Motion Block Video codec.
So I started to test plan B. Always have plan B. My plan B was to use OBS software to record the video and audio from that DOSbox window. OBS open source TV studio is an excellent video software to mix video from different sources (cameras, computer screen etc..) together to a single video output. In my case I just needed one video source (DOSbox window) and one audio audio source (computer sound output). OBS worked OK for me to record video easily and also sound after some testing. Finally I could report.
I got demo recorded successfully with DOSbox+OBS to video file and uploaded it to YouTube.
My capture: https://www.youtube.com/watch?v=UP1BPI8YfBo
Other capture with real old PC by Michael Huth at https://youtu.be/_nPjEK7ZfBU