Recording

Recordings are made by the game itself and saved on the machine running KSP, in GameData/JustReadTheInstructions/Web/recordings/. Live feeds and the stream URLs you give OBS are always MJPEG: the codecs below only apply to recordings.

Recording a camera

Each camera card on the main page has a Record button. Recording:

• keeps going if you close or reload the page;
• leaves a playable file if the game crashes;
• holds the camera's sound, as heard from where the camera is (AAC, 48 kHz stereo). See Sound.

Files are named [camera name]__cam[id]__[yyyy-mm-dd]_[hhmmss].mp4. Characters a file name cannot hold are replaced with _, and a second recording in the same second gets a _1, _2... suffix.

Example: Booster_Cam__cam10__2026-09-25_210455.mp4 is the camera named "Booster Cam", ID 10, recorded on 2026-09-25 at 21:04:55.

The Recordings button at the top of the page lists every recording, newest first. Play opens one in a new tab and Download saves a copy to the device you are using, so you can open the web UI from another machine and copy a recording to it.

What a recording is

Every recording is an MP4 at the camera's render resolution, at a constant frame rate (Max FPS), with a keyframe every 2 seconds and a bitrate of 0.2 bits per pixel per frame (about 12 Mbps at 1080p 30 FPS).

Choosing a codec

Warning

Keep H.264 unless you know your tools handle something else. H.264 opens in every editor, player, phone and OBS setup. Other codecs are for people who have checked that their whole workflow supports them.

Open Settings in the web UI and choose a Video codec. Only codecs that work on the machine running KSP are listed, and the choice is remembered per browser. JRTI's in-game settings window (Ctrl + Alt + F8) shows which encoders were found.

JRTI picks the first encoder that works, trying graphics card encoders before CPU encoders:

Codec	Windows	Linux	macOS
H.264 (default)	Media Foundation: graphics card, or Windows' own software encoder	h264_nvenc → h264_vaapi → h264_qsv → h264_vulkan → libx264 → libopenh264	h264_videotoolbox → libx264 → libopenh264
AV1	With ffmpeg: av1_nvenc → av1_amf → av1_qsv → av1_vulkan → libsvtav1	av1_nvenc → av1_vaapi → av1_qsv → av1_vulkan → libsvtav1	libsvtav1 (Apple chips have no AV1 encoder)

About AV1

JRTI gives AV1 the same bitrate as H.264, so files are about the same size but keep more detail. Recent VLC, mpv and web browsers play AV1, and Windows needs Microsoft's AV1 Video Extension to preview it. Check that your editor imports AV1 before recording anything important with it.

ffmpeg

Windows

H.264 needs nothing extra. AV1 needs ffmpeg.exe, for example from gyan.dev or BtbN, on your PATH or in GameData/JustReadTheInstructions/PluginData/ffmpeg/. JRTI then also uses it for H.264 if Media Foundation is missing (Windows N editions).

macOS

Recording goes through ffmpeg, which must be installed (for example with Homebrew: brew install ffmpeg), or placed in GameData/JustReadTheInstructions/PluginData/ffmpeg/, which JRTI checks first.

Linux

See Linux and Proton, including KSP running through Proton.

Checking your ffmpeg

To see which encoders your ffmpeg build has:

ffmpeg -hide_banner -encoders | grep -E "264|av1"

Which encoder runs on what

Encoder	Runs on
*_nvenc	NVIDIA graphics cards. AV1 needs an RTX 40 series or newer
*_amf	AMD graphics cards on Windows. AV1 needs an RX 7000 series or newer
*_vaapi	AMD and Intel graphics cards through Mesa or Intel's media driver. AV1 needs an AMD RX 7000 series, Intel Arc, Intel Core Ultra or newer
*_qsv	Intel graphics. AV1 needs Intel Arc, Intel Core Ultra or newer
h264_videotoolbox	Macs
*_vulkan	Graphics cards through Vulkan, when the encoders above are unavailable
libx264, libopenh264, libsvtav1	The CPU. Slower, and can drop frames at high resolutions while KSP is running

Record stays off

If the game cannot record (no encoder found), Record stays off and JRTI's settings window in KSP (Ctrl + Alt + F8) says why. On Linux and Proton see Linux and Proton.