Capturing videos

In order to capture videos there are at least two options which differ significantly.

Frame output system + ffmpeg

This method consists on outputting an image to a file every frame using the Frame output of Gaia Sky to later gather them to create a video using a video encoder software such as ffmpeg, which works on Windows, Linux and OS X.


Use F6 to activate the frame output mode and start saving each frame as an image. Use F6 again to deactivate it. When the frame output mode is active, the icon frameoutput is displayed at the top-right corner of the screen.

When the frame output system is active, each frame is saved as a JPEG image to disk. Refer to the Frame output section to learn how to configure the frame output system.

Once you have the image frames you can encode a video using a ffmpeg preset (slow, veryslow, fast, etc.) with the following command:

$ ffmpeg -framerate 60 -start_number [start_img_num] -i [prefix]%05d.jpg -vframes [num_images] -s 1280x720 -c:v libx264 -preset [slower|veryslow|placebo] -r 60  [out_video_filename].mp4

Please note that if you don’t want scaling, the --framerate input framerate, -r output framerate and -s resolution settings must match the settings defined in the frame output system preferences in Gaia Sky. You can also use a constant rate factor -crf setting:

$ ffmpeg -framerate 60 -start_number [start_img_num] -i [prefix]%05d.jpg  -vframes [num_images] -s 1280x720 -c:v libx264 -pix_fmt yuv420p -crf 23 -r 60  [out_video_filename].mp4

You need to obviously change the prefix and start number, if any, choose the right resolution, frame rate and preset and modify the output format if you need to.

ffmpeg is quite a complex command which provides a lot of options, so for more information please refer to the official ffmpeg documentation. Also, here is a good resource on encoding videos from image sequences with ffmpeg.

OpenGL context recorder

There are several available options to record OpenGL rendering to videos, in all systems. Below are some of these listed. These methods, however, will only record the OpenGL scene as it is displayed in the screen and are limited to its resolution.


  • glc/glcs - Command-line interface applications. The documentation and user guides can be found in this wiki.
  • Gamecaster - Front end to glc.
  • Soul Capture - Front end to glc.