[Howto] Record video from DOSBox

Last updated on 8 years ago
Eino
I got a private message asking about DOSBox recording. I thought it might be useful to have some sort of simple guide for getting started. There doesn't seem to be much information about how to go on about this besides key combination to get the built-in AVI recording activated. I've personally recorded DOS games by two different methods.

1. Built-in AVI recording option in DOSBox is activated by pressing CTRL+ALT+F5 and stopped by same combination. Filesizes you get with this option are quite small. Also, you can record games with a slow computer because recorded video will run smooth (if you have DOSBox configured properly, mainly cycles are important) even if game lags while recording. Unfortunately, if you have many AVI segments recorded by this method and join them together, audio and video will get more out of sync each time you add more recorded clips together. If there are not many segments desync shouldn't be noticeable since lag for each added video is small. Otherwise you'll have to export audio to wav and fix the desync manually with an audio editing program.

There are still more problems though. For example if game uses more than one resolution (many high resolution games have menus, cutscenes etc. in 320x200) files can't be added together without doing some extra steps since DOSBox records videos with different resolutions at different framerate + stops and restarts recording each time resolution is changed. Also if you are playing a game with additional CD audio, it doesn't get recorded. Finally, this method can cause heavier games, requiring high cycle rates, to lag during recording making it difficult / annoying to play even if recorded video looks fine.

2. Way easier option with problem cases mentioned is to use FRAPS. I don't recommend using it unless you have to, especially if you are not at all familiar with DOSBox settings. Unlike the built-in capture FRAPS will record screen as determined by dosbox.conf. For example if you have filters or screen stretching active, it will show up on video.

To record with FRAPS you have to set up 'output' in DOSBox.conf into FRAPS supported mode such as OpenGl. While using FRAPS however if the game lags while recording, the lag will show up on video. Also with FRAPS you might get extra borders around the game screen depending on your DOSBox configuration. You have to use 'crop' option at post-processing to get rid of borders and get a correct resolution.

Most DOS games, especially the older ones run in 320x200 resolution so you should double such resolution while processing the video. If you plan to use FRAPS, guide by JonL for recording PC games might also be helpful.

Links:

DOSBox Wiki for video recording:
http://www.dosbox.com/wiki/Recording_Video

DOSBox forums for DOSBox and DOS game support:
http://vogons.zetafleet.com/

PS. I give full permission to people managing the forum to edit this text as seen fit. All corrections and suggestions improving this topic in any way are welcome. Hope to see more DOS longplays in the future.
Oddbrother
Let's not forget that several DOS games can run in variable framerates.

Do we know if DOSBox's recorder compensates for the game's preference, or will almost always record in a non-standard frame rate of 70 fps? Because when I recorded a game like that, there was some slight frame tearing here and there.
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