Quick Start¶

Get from nothing to a labeled frame in about five minutes.

1. Open the app¶

2. Open a project — or start one¶

If you already have a .slp file, drag it onto the window, or use File ▸ Open Project… (Cmd+O / Ctrl+O).

.pkg.slp files with embedded videos work too, and open with no further setup — the frames come out of the file itself.

To start fresh, use File ▸ New Project… (Cmd+N / Ctrl+N):

1. Pick a Skeleton — one of the built-in templates (fly, mouse top-down, human, C. elegans) or Empty — define later.
2. Add videos: drag them onto the dropzone or click it to browse. No video handy? Click Use sample video to download mice.mp4.
3. Click Create Project.

3. Move around the video¶

The seekbar under the video marks labeled frames, shows track occupancy bars, and can plot a per-frame statistic behind them — instance count, point displacement, prediction score, and more. See Navigation.

4. Place an instance¶

1. Press Cmd+I / Ctrl+I (or Labels ▸ Add Instance) to drop a new instance on the current frame.
2. Drag nodes to their correct positions.
3. Nodes you can't see should be marked non-visible rather than guessed — right-click the node ▸ Mark Node Non-Visible.
4. Cmd+Z / Ctrl+Z undoes anything.

Have more than one animal in the frame? Hold Ctrl and drag a node of an existing instance to clone it (it's Ctrl on macOS too, not Cmd), or right-click ▸ Add Instance.

More in Labeling Instances.

5. Pick better frames to label¶

Labeling consecutive frames is mostly wasted effort — neighboring frames look almost identical. Open the Suggestions panel and generate a set of frames spread across the video instead:

• Stride — evenly spaced, the sane default
• Random — uniform random sample
• Frame chunk — every frame in one range
• Image features — decodes frames, clusters them, and picks a diverse set
• Prediction score / Velocity / Max displacement — target frames a model already struggles with

Then move through them with Space / Shift+Space.

See Suggestions.

6. Save¶

Cmd+S / Ctrl+S saves back to .slp. The first save of a new project suggests the name labels.v001.slp. File ▸ Save As… writes a new file and suggests the next version (labels.v002.slp, …).

The app also keeps a background draft of unsaved work, so a crashed tab or a closed window doesn't cost you labels — you get a Restore unsaved work? prompt next time. It's a safety net, not a substitute for saving.

What next?¶