This is a short instruction on how to capture the output of old DOS programs/demos to video with DOSBox.
Download DOSBox and install it to some location on your harddrive. I currently use v0.74. Take a look at the DOSBox game compatibility list or DOSBox demo compatibility list to check if the demo is known to (not) run. Some demos are uncapturable in DOSbox, some use unsynched routines that may run too fast or they switch resolutions very often...
Edit the configuration file "dosbox.conf" located in the install folder. Make the following (recommended) changes:
Still reading? Wow, you're tough... Btw, you can download a template dosbox.conf here if you want to. Change the paths etc. you find in the "<TAGS>" to match your setup.
language=<YOUR_LANGUAGE>.lng (you can get language files from the DOSBox download site)
machine=svga_s3 (change to 'vgaonly' for demos of the pre'95 era that use lots of vga tricks)
captures=<VIDEO_PATH> (path your videos will go to)
memsize=31 (some programs seem to have problem with high numbers here)
core=auto (if you have problems with this, try to change it to "normal")
cycles=fixed 40000 (the startup cycle count)
cycleup=5000 (increase cycle count by this on CTRL-F12)
cycledown=5000 (decrease cycle count by this on CTRL-F11)
("max" for DOSBox versions < 0.70)
You might need to enable/disable some memory types if you have problems running certain programs...
mount C: <YOUR_EXECUTEABLE_PATH> (base directory all your DOS files reside in)
keyb <YOUR_COUNTRY> (get keyb and language files here)
Take a look at the conversion page for tips on compressing the resulting videos to a final, suitable format.
- Ok, now you can start dosbox.exe and should see the startup screen and prompt. C:\ should now show the contents of <YOUR_EXECUTEABLE_PATH>. Change to the directory of the program you want to run.
- You might need a DOS extender. You can get the famous DOS/4GW from here or here. There's also a free DOS/4GW-compatible extender called DOS32. Some programs might need CWSDPMI to run.
- Use CTRL-F12 (increase cycles) and/or CTRL-F11 (decrease cycles) to set the cycle count you think that is appropriate for the program you want to run. This depends on the needs of the program. The processing power of your CPU will determine if the output will be fluent...
- Start capturing to video with CTRL-ALT-F5. You can make screenshots with CTRL-F5.
- Run the program. DOSBox should switch the window size to the current resolution the program uses and create video files. Do not give up if the display is flickering and the sound is stuttering. Be patient and wait for the program to finish, the video will be captured just fine!
- Now check the video file written to <VIDEO_PATH>. If the framerate is too low, you need to capture the program again, with a higher cycle count. If the sound is not ok, try choosing a different audio device (gus/sbpro/sb16). There might be more than one video file if the program changes resolutions. You can ignore/delete some of them (e.g. DOS command line) and may need to scale and combine others to get the complete capture file.
- The video will be captured with ~70 frames using the ZBMV-codec built into DOSBox. Audio should be 44.1kHz, 16Bit, Stereo. The codec is located in the "\zmbv" subdirectory of DOSBox if you want to install it.
If you want you can contact me: