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Your First Annotation

In SwimLab, annotations are markers you place on a video to capture key moments — race start, turns, breakouts, and finish. Once you’ve placed the right markers, SwimLab automatically calculates your split times.

This guide walks you through annotating a simple 100m freestyle race.

The Annotate Screen

When you open a race video, you’re in the Annotate screen. Here’s the layout:

┌─────────────────────────────────────────────────────┐
│  Video Player                    │  Marker Panel     │
│  (large, centre)                 │  (right sidebar)  │
│                                  │                   │
│  [Play] [◄◄] [frames] [frames►] │  Marker list      │
│  Timeline ──────────────────── ─┤  + Add Marker     │
└─────────────────────────────────┴───────────────────┘
         ▲ Splits Table appears below the player
  • Video player — scrub or play your footage
  • Marker panel — lists all markers in time order
  • Timeline — shows markers as colour-coded pins; click to jump to any marker
  • Splits table — calculated automatically as you add markers

Place Your First Markers

Find the start

Play the video and pause at the exact frame the swimmer leaves the blocks (or wall, for non-start laps). Use the ← → arrow keys to move one frame at a time.

Add a Start marker

Press S on your keyboard, or click + Add Marker → Start in the marker panel. A blue pin appears on the timeline.

Find the first turn

Scrub forward to the moment the swimmer touches the wall at the turn. Pause on the exact frame.

Add a Turn marker

Press T on your keyboard, or click + Add Marker → Turn. An orange pin appears.

Find the finish

Scrub to the finish — the frame where the swimmer’s hand touches the wall. Pause.

Add a Finish marker

Press F on your keyboard, or click + Add Marker → Finish. A green pin appears.

Review your splits

The splits table now shows the time from Start → Turn and Turn → Finish automatically. For a 100m freestyle you’ll see two splits.

Frame-accuracy matters. A single frame at 60fps is ~16ms. For competitive splits, always use the arrow keys to find the exact frame rather than clicking on the timeline.

Editing and Deleting Markers

  • Move a marker — click the marker in the panel and drag the blue handle on the timeline to the correct frame
  • Rename a marker — double-click the marker name in the panel to edit it
  • Delete a marker — click the marker in the panel and press Delete, or click the trash icon

Save Your Annotations

Annotations save automatically as you work. You’ll see a Saved indicator in the top-right corner. There’s no save button to click.

What’s Next?

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