rhythr

rhythr is an unofficial community tool that turns Rhythia (.rhr) replays into videos. It is not affiliated with or endorsed by Rhythia or Capo Games.

Download from the releases page, then start it and drop a replay into the window: the map downloads itself, a live preview appears and Render video does the rest. Your game install is detected on startup (the Game card reports it, and carries Detect / Locate… for installs in unusual places), so built-in skins use its own textures and colors. Rendering works without it. GPU renderer (wgpu) aiming for pixel-parity with the game, so a rendered video looks exactly like watching the replay in-game with your own skin.

Step by step, including how to export a replay and your skin from the game: the user guide.

• Windows: rhythr_x.y.z_x64-setup.exe. Click through SmartScreen ("More info" → "Run anyway"; the installer is not code-signed).
• Linux (any distro): rhythr_x.y.z_amd64.AppImage. One self-contained file (ffmpeg included): chmod +x, run. Needs glibc 2.35+ (Ubuntu 22.04 / Debian 12 / Fedora 36 or newer, Arch, openSUSE Leap 15.6+, SteamOS 3.5+). If it won't start, install your distro's fuse3/fuse package (the runtime needs a fusermount binary), or run with --appimage-extract-and-run.
• Debian/Ubuntu/Mint: rhythr_x.y.z_amd64.deb (sudo apt install ./rhythr_*.deb; uses the system ffmpeg and registers the .rhr file type).
• Fedora/openSUSE: rhythr-x.y.z-1.x86_64.rpm. Install ffmpeg separately (RPM Fusion on Fedora) or use the AppImage.
• Arch-based (Arch, CachyOS, Manjaro, EndeavourOS, …): install rhythr-bin from the AUR. Recommended over the AppImage there: a native install against your rolling-release system libraries, no FUSE involved.

The game runs through Proton on Linux; the startup scan finds the Steam (native, Flatpak or Snap) install and reads the built-in assets from it just like on Windows.

Status: working end-to-end. Parsers, integrity check, the GPU renderer (pixel-calibrated against real footage: notes, skins, HUD, results screen) and a desktop app are functional, with Windows and Linux packages on the releases page.

Screenshot

Placeholder: no screenshot is committed yet.

Anti-cheat statement

This tool is a strict read-only renderer:

• No code path writes or re-encodes .rhr files: there is no replay serializer in this codebase, and none will be accepted.
• Nothing can alter cursor positions, hits, misses, timing, accuracy or mods. Only visuals are configurable (skin, camera, HUD, resolution, FPS).
• Every replay is run through an integrity check: hits/misses/accuracy are re-derived from the raw input frames and compared against the header. On mismatch the tool warns loudly and burns a "replay data inconsistent (possibly manipulated)" notice into the rendered video.
• This check (and any rendered video) is a heuristic by this tool. It is not an official Rhythia score verification.

Workspace

Crate	Purpose
crates/formats	Read-only parsers: .rhr replays (all 5 version gates), map cache JSON, .rhm
crates/sim	Hit registration (frame flags → per-note results), integrity check
crates/render	wgpu GPU renderer: scene, skins/.rhs import, HUD, results screen, video export
crates/cli	rhythr-cli binary: info, verify, check, frame, video
crates/gui	Desktop app (Tauri): preview + scrubber, HUD overrides, map auto-download, video export

cargo run -p rhythia-cli -- info testdata/pass_long_score77.rhr
cargo run -p rhythia-cli -- verify testdata/fail_score131.rhr --map testdata/fail_map_map_json.json
cargo run -p rhythia-cli -- check testdata

# A single still frame:
cargo run -p rhythia-cli -- frame testdata/pass_long_score77.rhr \
    --map testdata/pass_long_map_map_json.json --at 1:30 -o frame.png

# A video clip (frames → ffmpeg + audio; needs ffmpeg on PATH):
cargo run -p rhythia-cli -- video testdata/pass_long_score77.rhr \
    --map testdata/pass_long_map_map_json.json --start 1:25 --end 1:37 -o clip.mp4

The renderer runs headlessly on the GPU (Vulkan), the same wgpu backend the game itself uses. The camera model (perspective FOV, note approach, grid placement) was derived from the game's own shaders and calibrated against real footage; no game code or assets are vendored.

Desktop app

cargo run -p rhythia-gui

Drop a .rhr anywhere in the window: the map auto-downloads from rhythia.com (hash-verified against the replay header and cached), the replay is integrity-checked (a "verified" / "inconsistent" badge on the replay card), and a live GPU preview with a scrubbable timeline (health graph + miss markers) appears. Individual HUD elements can be toggled per user preference. Overrides persist across restarts and apply to every render. Building the Windows installer: see docs/WINDOWS-BUILD.md.

testdata/ holds real replays verified against the game's own database (testdata_manifest.json). Audio/cover files are third-party content and are not part of the repository.

Attribution

The .rhr wire format was verified against three independent sources: the official parseRhr in the rhythia.com web bundle, yo-ru/rhrParse (MIT) and gerhaarrd/rhr2mp4 (MIT), plus 311 local replays.

License

MIT. See LICENSE.