Breez

Record your product. Make it beautiful. Ship the demo.

Breez is a lightweight, opinionated screen recorder and demo editor for developers and product teams, written entirely in Rust. It is not a general-purpose video editor: one recording, a handful of high-leverage effects (zoom, styled backgrounds, click highlights, music), and a fast MP4 export.

Workflow: Record -> Trim -> Zoom & pan -> Style background -> Music -> Export

Why Breez

• Lightweight. Native code, immediate-mode UI, no Electron, no browser runtime. Frames stream straight from the capture backend into the encoder.
• Crash-safe by design. Recordings are fragmented MP4; if the app or machine dies mid-take, everything up to the last fragment is playable.
• Non-destructive. Editing only mutates a small JSON file. Your recorded media is never rewritten until you explicitly export.
• Open format. A .rec project is a plain directory of standard media files plus JSON. Nothing proprietary, inspect it with ffprobe and cat.

The .rec format

A Breez project is a directory package containing standard streams, no custom binary containers:

MyDemo.rec/
  manifest.json          # format tag + crash-recovery flag
  project.json           # timeline + style (the only file edits touch)
  media/
    screen/take-000.mp4  # fragmented MP4 video, crash-recoverable
    audio/system-000.m4a # AAC system audio
    music/               # imported tracks (copied in, self-contained)
  events/
    input-000.jsonl      # normalized mouse/keyboard events
  cache/                 # thumbnails, waveforms (disposable)

Architecture

Cargo workspace, one concern per crate:

Crate	Purpose
breez-core	Project model, timeline, .rec package I/O, input event log
breez-capture	Capture session (via pinray) -> encoded streams + event log
breez-codec	Encode/decode behind our own API (ffmpeg-sidecar as the first backend, fully internal)
breez-render	Frame compositor: wallpaper, zoom, radius, shadow, click ripples
breez (app)	egui/eframe UI: record view, editor, timeline

Design rules that keep it fast and small:

• No async runtime: std threads + channels, the UI thread never blocks on IO
• ffmpeg runs out-of-process and never leaks into public APIs; hardware encoding (VAAPI/VideoToolbox/NVENC/QSV) is a flag, not a rewrite
• Frames travel as Arc<[u8]>, decoded on demand into a bounded cache

Building

Requires Rust 1.88+. The ffmpeg binary is downloaded automatically on first run.

git clone https://github.com/Itz-Agasta/breez.git
cd breez
cargo run -p breez

Development checks:

cargo fmt --all --check
cargo clippy --workspace --all-targets
cargo test --workspace

Platform notes

Platform	Capture	Input events
Linux Wayland	Display via desktop portal	Not available (portal limitation), effects degrade gracefully
Linux X11	Display, window best-effort	rdev listener
macOS / Windows	Planned via pinray backends	rdev listener

Roadmap (MVP)

• Workspace scaffold, CI, frameless themed window
• Headless capture core: screen + system audio -> .rec
• Record flow + editor shell
• Playback, scrubbing, and trim
• Zoom & pan keyframes with cursor-follow
• Music import, waveforms, fades
• MP4 export (H.264 + AAC, hardware encode when available)
• Polish: undo/redo, autosave, crash recovery flow

Post-MVP: microphone/voiceover, camera bubble, re-rendered cursor, captions, GIF/WebM export.