Capture
dosbox-automation can capture screenshots, record audio, and record video
directly from the emulator. By default, all captures are saved to the
capture directory in the current working directory. You can change this with
the capture_dir setting.
Screenshots
Screenshots can be saved in multiple formats: upscaled (sharp pixels, aspect-corrected), rendered (post-shader, exactly what you see on screen), or raw (the framebuffer's contents with 1:1 pixel aspect ratio).
Use Ctrl+F5
/ Cmd+F5
to take a screenshot using the default format(s)
configured by the default_image_capture_formats
setting.
Video capture
Press Ctrl+F7 / Cmd+F7 to start and stop video recording. The video is captured as a lossless AVI file.
When capture is started through the REST API or a Lua script, it can record either the raw emulator frames or the rendered display as seen on the screen. The hotkey always records raw frames.
Raw vs rendered
The two modes answer different questions.
Raw records what the emulated video hardware produced: the framebuffer at the game's native resolution (say 320x200), with frames arriving exactly as the emulation generates them. No shaders, no scaling, no window influence. This is the mode for archiving, regression testing, and pixel-exact comparison between runs: the same game doing the same thing produces the same frames on any machine, regardless of window size or shader settings.
Rendered records what you actually see: the post-shader image at window resolution, at a constant frame rate matching the video mode. CRT shader, aspect correction, and integer scaling are all baked into the recording. This is the mode for demo footage and for documenting how something really looked on screen. The cost: output depends on your window size and shader settings, and encoding the larger frames happens on the emulation thread, so very large windows can slow the emulation while recording.
Both modes encode to lossless ZMBV inside an AVI container; transcode
with ffmpeg if another codec is needed. The single-frame grab
(/api/v1/video/frame) takes the same mode parameter, so a script
can pull one rendered screenshot without starting a recording.
Recording stops on its own before the capture drive runs out of space
(see capture_min_free_space_mb below), and a write error such as a
full disk or a removed device ends the recording with a log message
instead of leaving a corrupt file. An interrupted AVI stays playable up
to the point of truncation.
Audio capture
Press Ctrl+F6 / Cmd+F6 to start and stop audio recording. Raw MIDI and OPL output can also be captured for those who want to tinker with game music outside the emulator.
Configuration settings
Capture settings are to be configured in the [capture] section.
capture_dir
Directory where the various captures are saved, such as audio, video,
MIDI, and screenshot captures (capture in the current working directory
by default).
capture_min_free_space_mb
Minimum free space on the capture drive, in megabytes. Video
recording stops cleanly when free space falls below this limit, so a
long recording cannot fill the disk. Set to 0 to disable the
check.
Possible values: a number in megabytes, 1024 (default)
default_image_capture_formats
Set the capture format of the default screenshot action.
If multiple formats are specified separated by spaces, the default screenshot action will save multiple images in the specified formats. Keybindings for taking single screenshots in specific formats are also available.
Possible values:
upscaled(default) -- The image is bilinear-sharp upscaled and the correct aspect ratio is maintained, depending on theaspectsetting. The vertical scaling factor is always an integer.rendered-- The post-rendered, post-shader image shown on the screen is captured. Filenames end with-rendered.raw-- The contents of the raw framebuffer is captured (always results in square pixels). Filenames end with-raw.