i3rs

An open-source, cross-platform alternative to MoTeC i2 Pro for motorsport telemetry analysis. Built entirely in Rust.

i3rs opens MoTeC .ld log files and provides time-series graphs, lap navigation, multi-panel workspaces, and cursor-synchronized analysis -- all in a single native binary with no runtime dependencies.

Features

• MoTeC .ld/.ldx parsing -- reads the binary log format produced by MoTeC M1 ECUs, including channel metadata, sample data, and lap timing from .ldx sidecar files
• Memory-mapped file access -- opens 100MB+ files instantly via memmap2; channel data is decoded on demand
• Min-max decimation -- renders 200+ channels at 60fps by downsampling to pixel resolution while preserving visual peaks and valleys
• Multi-channel graphs -- overlay or tiled modes, dual Y-axes, color-coded lines, drag-and-drop channels
• Lap detection & navigation -- parses lap boundaries from data or .ldx files, lap markers on the timeline, click-to-zoom
• Dockable panel layout -- multiple graph panels, channel browser, cursor readout, and timeline overview in a resizable tabbed workspace
• Cross-panel synchronization -- cursor position and zoom range stay in sync across all panels
• Workspace persistence -- save and load panel layouts to JSON; multiple worksheet tabs
• Cross-platform -- runs on macOS, Windows, and Linux via wgpu backends (Vulkan/Metal/DX12/OpenGL)

Building

Requires Rust 2024 edition (rustc 1.85+).

cargo build --release

Usage

GUI Application

# Open with file picker
cargo run --release -p i3rs-app

# Open a specific file
cargo run --release -p i3rs-app -- path/to/session.ld

You can also drag and drop .ld files onto the application window.

CLI

Print session metadata and channel statistics (min/max/mean) for a log file:

cargo run --release -p i3rs-cli -- path/to/session.ld

Project Structure

crates/
  i3rs-core/    Core library: .ld/.ldx parsing, data model, lap detection, downsampling
  i3rs-app/     Desktop GUI application (egui + egui-dock)
  i3rs-cli/     Command-line file inspector
docs/
  PLAN.md           Development roadmap (Milestones 1-9)
  ld-file-format.md MoTeC .ld binary format specification
test_data/
  VIR_LAP.ld        Sample telemetry log (~4.8MB, single lap at Virginia International Raceway)
  VIR_LAP.ldx       Associated lap metadata (XML sidecar)

Key Dependencies

Crate	Purpose
memmap2	Zero-copy memory-mapped file access
half	IEEE 754 float16 decoding
eframe / egui	Immediate-mode GUI framework
egui_plot	Line chart rendering with pan/zoom
egui-dock	Dockable, tabbable panel layout
quick-xml	.ldx sidecar XML parsing
rfd	Native file open dialogs

Test Data

The test_data/ directory contains a small sample dataset for development and testing:

• VIR_LAP.ld -- a single-lap telemetry recording from Virginia International Raceway (~4.8MB)
• VIR_LAP.ldx -- the accompanying XML sidecar with lap timing data

These files are produced by a MoTeC M1 ECU and exercise the full parsing pipeline: header, event/venue/vehicle metadata, channel metadata linked list, and multi-type sample data.

Roadmap

See docs/PLAN.md for the initial roadmap.

License

MIT