Capturing videos

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

Frame output system + ffmpeg

The frame output system enables automatic saving of every frame to an image file to disk with an arbitrary resolution and a user-defined frame rate. The image files can later be encoded into a video using video encoder software such as ffmpeg.

Note

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 JPG or PNG 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/Screen recorders

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

Linux

Windows

  • OBS Studio – amazing open source capturing and streaming solution.

  • FRAPS – 3rd party Direct3D and OpenGL recording software.

  • NVIDIA Shadowplay – only for NVIDIA cards.