The timeline was the only place that reconstructed audio-layer clip instances from a backend snapshot (build_audio_clip_cache) instead of reading the document like every other layer type. But the document is the actual source of truth: clip actions mutate *Layer::clip_instances, it's what persists to .beam, and it drives the backend on load. The snapshot is downstream of it. That dual source caused the second-recording preview bug: a recording clip lives only in the document (its backend clip has a temporary pool index of 0, so the snapshot can't represent it). layer_clips() only fell back to the doc when the snapshot cache was *empty*, so the first recording previewed but the second — once the layer already had a finalized clip — was dropped and showed as zero-length until finalized. Fix: make layer_clips() read <layer>.clip_instances for audio too, and delete build_audio_clip_cache + the audio_cache plumbing threaded through ~7 methods and ~25 call sites. Recording clips grow via the existing RecordingProgress / MidiRecordingProgress mirror to the doc; finalized clips come from the actions; both states now live in one place. Root fix this exposed: get_clip_duration() wrapped every audio clip's duration as Seconds, but MIDI clips store their duration in BEATS (they share AudioClip with sampled clips). The snapshot had masked this by always forcing a MIDI clip's timeline_duration; reading from the doc requires the value to be right, so get_clip_duration now converts a MIDI clip's beats duration to seconds. Net -120 lines. Whole workspace compiles; 299 core tests pass. The piano roll still uses the snapshot for its own MIDI editor (separate pane, out of scope). |
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|---|---|---|
| .github/workflows | ||
| daw-backend | ||
| docs | ||
| ffmpeg-blob-io | ||
| lightningbeam-core | ||
| lightningbeam-ui | ||
| nam-ffi | ||
| packaging | ||
| screenshots | ||
| scripts | ||
| src | ||
| tests | ||
| vendor | ||
| .gitignore | ||
| .gitmodules | ||
| ARCHITECTURE.md | ||
| BEAM_FILE_FORMAT.md | ||
| CONTRIBUTING.md | ||
| Changelog.md | ||
| LICENSE | ||
| README.md | ||
| STREAMING_TO_DISK_PLAN.md | ||
| TODO.md | ||
| beam_inspector.py | ||
| beam_inspector_README.md | ||
| create_release.sh | ||
| package.json | ||
| phone-ui-sketches.html | ||
| pnpm-lock.yaml | ||
README.md
Lightningbeam
A free and open-source 2D multimedia editor combining vector animation, audio production, and video editing in a single application.
Screenshots
Features
Vector Animation
- GPU-accelerated vector rendering with Vello
- Draw and animate vector shapes with keyframe-based timeline
- Non-destructive editing workflow
- Paint bucket tool for automatic fill detection
Audio Production
- Real-time multi-track audio recording and playback
- Node graph-based effects processing
- MIDI sequencing with synthesizers and samplers
- Comprehensive effects library (reverb, delay, EQ, compression, distortion, etc.)
- Custom audio engine with lock-free design for glitch-free playback
Video Editing
- Video timeline and editing with FFmpeg-based decoding
- GPU-accelerated waveform rendering with mipmaps
- Audio integration from video soundtracks
Technical Stack
Current Implementation (Rust UI)
- UI Framework: egui (immediate-mode GUI)
- GPU Rendering: Vello + wgpu (Vulkan/Metal/DirectX 12)
- Audio Engine: Custom real-time engine (
daw-backend)- cpal for cross-platform audio I/O
- symphonia for audio decoding
- dasp for node graph processing
- Video: FFmpeg 8 for encode/decode
- Platform: Cross-platform (Linux, macOS, Windows)
Legacy Implementation (Deprecated)
- Frontend: Vanilla JavaScript
- Backend: Rust (Tauri framework)
Project Status
Lightningbeam is developed on the main branch. The project has been rewritten from a Tauri/JavaScript prototype to a pure Rust application to eliminate IPC bottlenecks and achieve better performance for real-time video and audio processing.
Current Status:
- ✅ Core UI panes (Stage, Timeline, Asset Library, Info Panel, Toolbar)
- ✅ Drawing tools (Select, Draw, Rectangle, Ellipse, Paint Bucket, Transform)
- ✅ Undo/redo system
- ✅ GPU-accelerated vector rendering
- ✅ Audio engine with node graph processing
- ✅ GPU waveform rendering with mipmaps
- ✅ Video decoding integration
- 🚧 Export system (in progress)
- 🚧 Node editor UI (planned)
- 🚧 Piano roll editor (planned)
Getting Started
Prerequisites
- Rust (stable toolchain via rustup)
- System dependencies:
- Linux: ALSA development files, FFmpeg 8
- macOS: FFmpeg (via Homebrew)
- Windows: FFmpeg 8, Visual Studio with C++ tools
See docs/BUILDING.md for detailed setup instructions.
Building and Running
# Clone the repository
git clone https://github.com/skykooler/lightningbeam.git
# Or from Gitea
git clone https://git.skyler.io/skyler/lightningbeam.git
cd lightningbeam/lightningbeam-ui
# Build and run
cargo run
# Or build optimized release version
cargo build --release
Documentation
- CONTRIBUTING.md - Development setup and contribution guidelines
- ARCHITECTURE.md - System architecture overview
- docs/BUILDING.md - Detailed build instructions and troubleshooting
- docs/AUDIO_SYSTEM.md - Audio engine architecture and development
- docs/UI_SYSTEM.md - UI pane system and tool development
- docs/RENDERING.md - GPU rendering pipeline and shaders
Project History
Lightningbeam evolved from earlier multimedia editing projects I've worked on since 2010, including the FreeJam DAW. The JavaScript/Tauri prototype began in November 2023, and the Rust UI rewrite started in late 2024 to eliminate performance bottlenecks and provide a more integrated native experience.
Goals
Create a comprehensive FOSS alternative for 2D-focused multimedia work, integrating animation, audio, and video editing in a unified workflow. Lightningbeam aims to be:
- Fast: GPU-accelerated rendering and real-time audio processing
- Flexible: Node graph-based audio routing and modular synthesis
- Integrated: Seamless workflow across animation, audio, and video
- Open: Free and open-source, built on open standards
Contributing
Contributions are welcome! Please see CONTRIBUTING.md for guidelines.
License
[License information to be added]


