RapidTimelapse - Companion for RapidRAW

An LRTimelapse-style keyframe ramping companion for RapidRAW. A native desktop app (Tauri: Rust backend, React/TypeScript UI) — no separate runtime to install.

Edit a handful of turning-point frames in RapidRAW, rate each one 5 stars, then use this app to smoothly interpolate every setting across the frames in between and write the result straight to their .rrdata sidecars. Refresh the folder in RapidRAW and export as normal.

Part of a family of apps by Chris Cork Photography, alongside RapidCulling and RapidRetouch.

New to RapidTimelapse? Watch the tutorial:

⬇ Download the latest version

Free and open-source, licensed AGPL-3.0.

Installing

Grab the latest build for your OS from Releases.

These builds aren't code-signed (that needs a paid developer certificate this project doesn't have yet), so your OS will warn that the publisher is unverified on first launch. That's expected for unsigned beta software, not a sign anything's wrong:

• macOS: Direct download (.dmg, Apple Silicon + Intel). Open the .dmg, drag RapidTimelapse.app into Applications. Gatekeeper will refuse to open it the first time — either right-click (Control-click) the app and choose Open, then confirm, or run this once in Terminal:

  xattr -d com.apple.quarantine /Applications/RapidTimelapse.app
  

• Windows: Direct download (.msi installer). Run the .msi or .exe. SmartScreen will show "Windows protected your PC" — click More info, then Run anyway.
• Linux: Direct download (.AppImage). chmod +x the .AppImage and run it directly (works on Debian, Arch, Fedora and most others), or install the .deb/.rpm for your distro. If the window opens blank, see Linux: blank/gray window below.

Workflow

1. Import the whole sequence into RapidRAW, select all, press 0 (or make any tiny edit) so every frame gets a .rrdata sidecar.
2. Edit your turning points — first frame, last frame, and anywhere the light changes direction — and rate each one 5 stars. A keyframe needs a real edit, not just a rating: RapidRAW only writes adjustment data once a slider actually moves (confirmed on 1.6.4 — a bare rating with nothing else touched can still leave adjustments: null). The app will warn you in the toolbar if a 5-star frame has no edits yet.
3. Open this app, Browse… to the folder, Scan Folder. 5-star frames are auto-selected as keyframes (toggle any frame's ☆ in the filmstrip to add/remove one). Adding a star here doesn't touch the file yet — see step 5.
4. Adjust Smoothing and watch the keyframe curve update live. Optionally enable Deflicker to flatten frame-to-frame brightness noise on top of the ramp (measured from each frame's own embedded preview).
5. Write Sidecars. Every non-keyframe frame's .rrdata is regenerated from the ramp; a keyframe's own adjustments (its real edit) is never touched. If you starred a frame in this app's filmstrip that wasn't already 5-star on disk, its rating is stamped to 5 at write time too (its edit still untouched) — so RapidRAW and the next scan agree it's a keyframe without you re-clicking it every session. A .rrdata.bak is kept per frame the first time it's touched, so Revert always restores your real pre-ramp state, however many times you re-run the ramp in between.

What's interpolated vs. carried over

Interpolated: exposure, contrast, highlights/shadows/whites/blacks, temperature/tint, vibrance/saturation, clarity/dehaze/structure, sharpness + noise reduction, vignette, grain, glow/halation/flare/lens-blur effect, the full 8-band HSL mixer, color grading wheels, color calibration, the parametric tone curve, and point/curve tone curves (when both bracketing keyframes have the same curve shape).

Carried from the nearest keyframe rather than blended — geometry and choices don't have a meaningful "halfway" value: crop, transform/rotation/flip, lens-correction profile and toggles, LUT choice, tone mapper, orientation.

Masks track when copied, not when redrawn. A mask is only ever carried wholesale like the above, unless it can be matched to a mask with the same ID on both bracketing keyframes — which happens when you create it on one keyframe and then copy/duplicate it (not redraw it from scratch) onto the others. A matched radial or linear gradient has its position, size and rotation smoothly interpolated across the frames in between (its own local exposure/contrast/etc. and opacity ramp too), so e.g. a radial gradient isolating the Milky Way, repositioned and rotated by hand on each keyframe to track its movement across the sky, follows a smooth path through every frame rather than jumping. Non-geometric mask shapes (brush, AI subject/sky, quick eraser) can't be tracked this way and are always carried as-is.

See src-tauri/src/params.rs for the exact field lists — the engine walks adjustments generically (ramp every number it finds except a short blacklist) so it stays correct if RapidRAW adds new sliders later.

Building / running

Requires Node 18+ and a Rust toolchain (see tauri.app/start/prerequisites).

npm install
npm run tauri dev      # run in development
npm run tauri build    # produce a native installer for the current OS

tauri build produces a .AppImage/.deb on Linux, .dmg/.app on macOS, and .msi/.exe on Windows — run it on each target OS (or via CI) to get that platform's installer; Tauri doesn't cross-compile installers from one OS to another.

Linux: blank/gray window

If the window opens but renders blank, WebKitGTK's GPU compositing path is failing on your graphics stack (seen as Failed to create GBM buffer... in the terminal). Force software rendering:

WEBKIT_DISABLE_DMABUF_RENDERER=1 WEBKIT_DISABLE_COMPOSITING_MODE=1 npm run tauri dev

For a built .AppImage/binary, set the same two environment variables before launching it, or bake them into a wrapper script / the .desktop launcher's Exec line.

Safety

• A keyframe's adjustments (its actual edit) are never modified by this app. The one exception: if you marked it a keyframe by hand and it wasn't already 5-star on disk, Write Sidecars stamps its rating to 5 so it's remembered — nothing else in the file changes.
• Every sidecar this app writes is backed up to <file>.rrdata.bak the first time it's touched (never overwritten on later runs), so Revert always gets you back to your real, pre-ramp edits.
• RAW files are never touched — only .rrdata sidecars, exactly like RapidRAW's own non-destructive workflow.

Known limits

• Frame order is filename order (natural/numeric-aware sort), which matches in-camera numbering almost always but isn't capture-time-aware.
• Tone curves with differing point counts or x-positions between the two bracketing keyframes fall back to carrying the nearest keyframe's curve rather than guessing at a blend.
• No RAW demosaic — filmstrip thumbnails and deflicker brightness both come from each RAW file's embedded JPEG preview (found by scanning for JPEG markers, format-agnostic), not RapidRAW's real GPU pipeline. Good enough to browse and measure exposure by; not a substitute for RapidRAW's own preview.

Layout

src-tauri/src/
  rrdata.rs       read/write .rrdata sidecars; unknown fields pass through untouched
  sequence.rs     scan a folder, natural-sort frames, pair with sidecars
  params.rs       which adjustment fields ramp vs. carry over; the JSON leaf walker
  interpolate.rs  the ramp engine: keyframes -> full per-frame plan
  deflicker.rs    measured brightness -> per-frame exposure correction
  preview.rs      embedded-JPEG extraction for thumbnails + brightness measurement
  commands.rs     Tauri commands exposed to the UI
src/               React/TypeScript UI (filmstrip, keyframe curve, data table)