Choose the boundary evidence
An event boundary can follow a visible movement, an audible cue, or an editorial transition. State which evidence controls the label. For a handoff, the beginning might be a reach or the moment an object leaves a surface. Both can be reasonable; inconsistency becomes a problem when annotators alternate between them without an agreed rule.
Represent overlap and uncertainty
Several events may happen at once, and some boundaries cannot be identified precisely. Decide whether annotations can overlap and how uncertain intervals are recorded. Do not force an exact timestamp merely because a file format accepts one. Explain whether labels describe an observed interval, a point event, or an estimate requiring review, and keep those meanings consistent.
Bind timestamps to the asset
Time references must identify the exact delivered video version. Trimming, speed changes, inserted introductions, and replaced audio can shift the relationship between labels and media. State the time unit and origin explicitly. Preserve original source offsets when clips are derived, and verify sample annotations by seeking to their boundaries in the actual delivered files rather than only reading the table.
Pilot disagreement handling
Ask reviewers to annotate the same varied clips and compare disagreements by event type. Refine the boundary guide and document how unresolved examples are handled. A review threshold should reflect the task rather than an unexplained universal tolerance. Discuss annotation scope, source feasibility, and acceptance procedures with the proposed collection before committing to a large temporal-labeling effort.
Review checklist
- Define visible or audible start and end cues.
- Choose overlap and uncertainty representation.
- Bind labels to exact media versions.
- Pilot shared clips and adjudicate boundary disagreements.