Spacecap

A hardware accelerated screen recording tool for Linux. Still in development (see features/roadmap below).

• Written in Zig (0.16.0).
• Video encoding with Vulkan Video (vulkan-zig).
• UI built with imgui/SDL3.
• Muxing/Audio encoding with FFmpeg.

Installation

# Spacecap will be installed to ~/.local/bin/spacecap

# Install
curl -LsSf https://spacecap.org/install | sh

# Uninstall
curl -LsSf https://spacecap.org/install | sh -s -- --uninstall

Features

• Desktop/window capture.
• Screen recording.
• Replay buffer - save last n seconds of video (buffered in memory).
• Capture preview.
• Global keybinds.

Roadmap

• Screenshots.
• Video player/editor.
  • Simple video editor (trim start/end).
  • File browser to select videos to edit.
• Windows support.

Requirements

• A GPU that supports Vulkan Video encoding.

NOTE: So far this has only been tested on an Nvidia GPU (RTX 3080). AMD will be supported, I just have no way of testing at this time.

Linux

• Wayland
• Pipewire

Windows

• Windows is not yet supported. Spacecap is architected in such a way that it can be cross platform. For Windows support, the audio/video capture interfaces need to be implemented. It's on the roadmap, but is not currently a priority.

Global Keybinds

Linux

xdg-desktop-portal global shortcuts can be used if your desktop environment supports it, otherwise the Spacecap CLI can be used to send commands.

e.g.

# Save replay
spacecap -s save-replay

# List available commands
spacecap -h

For example, here is what a config in niri would look like:

binds {
    Mod+Shift+R hotkey-overlay-title="Spacecap: save replay" { spawn-sh "spacecap -s save-replay && notify-send 'Spacecap' 'Replay saved'"; }
}

Development

Nix is required for development.

# Build
nix develop -c zig build -Dnix

# Run
nix develop -c zig build run -Dnix

# Test
nix develop -c zig build test -Dnix

Logging

By default, Spacecap only writes error logs to error.log. Set the SPACECAP_LOG_LEVEL environment variable to debug, info, warning, or error.

Crash logs are written to crash.log, which happens when a panic occurs.

Log Location

• Linux: $XDG_CONFIG_HOME/spacecap, or $HOME/.config/spacecap
• Windows: %APPDATA%\spacecap.

Troubleshooting

Linux restore capture source stops working

Spacecap uses the XDG desktop portal screencast permission store to restore the previous capture source. If the portal permission database gets corrupted, restore may stop working even after selecting a source again. This has happened to me after my main disk filled up unexpectedly.

To reset only the screencast portal permissions, delete the database and then reboot.

# Delete
rm ~/.local/share/flatpak/db/screencast ~/.local/share/flatpak/db/screencast.bak

# OR move it to a backup
mv ~/.local/share/flatpak/db/screencast ~/.local/share/flatpak/db/screencast.bak

reboot