Splits

A split is a moment in a run that matters — the start of the track, the finish, or an intermediate checkpoint. Splits define the section boundaries Racecraft uses to compute per-section times, leaderboard ranks, and time deltas.

The shape of a split

A split has:

• a type — one of start, intermediate, or finish
• a time within the run, in milliseconds from the start of the video
• an order in the run (start first, finish last, intermediates in between)

Every run has exactly one start and one finish split. Intermediate splits are optional; most tracks benefit from three to six.

Splits on the reference run vs target runs

Splits are marked manually only on the reference run. Every other run in the same session is aligned against the reference, and its splits are predicted automatically at the same checkpoints.

The user reviews predicted splits and confirms them. Racecraft never silently overwrites a split a user has confirmed — manual edits are preserved across re-predictions.

What splits are used for

• per-section times. Without splits there's only total time; with splits, you can see how each section played out.
• leaderboard ranking. A run's total time is measured from its start split to its finish split, against the same window on the reference.
• alignment anchoring. The reference run's splits are used as anchors when aligning target runs to the reference. Splits placed on visually distinctive frames produce more reliable alignment for every other run.

Where to place splits

The reference run's splits should sit on visually distinctive frames — corners, gates, transitions between sections. Long uniform stretches (dense forest, featureless fire road, sky-only after a jump) are harder to anchor.

Racecraft suggests reference splits automatically based on a distinctiveness measure of the video. You can accept the suggestions, move them, add your own, or remove ones you don't want.

Number of splits

• 1 start + 1 finish is the minimum
• 3–6 intermediates is the common range for most tracks
• short tracks (under ~15 seconds) may have no intermediates — the run is too brief for section-level analysis to add much

Confirmed vs unconfirmed splits

Predicted splits on a target run are unconfirmed until the rider reviews them. Unconfirmed splits don't drive re-prediction of other runs and don't lock in the comparison; once confirmed, the run is ready for analysis and lands on the leaderboard.

This is the lever that lets you re-suggest splits without overwriting work — confirmed splits are user intent and are preserved.