What are word-level timestamps? Word locations, caption grouping, and precision
Understand word boundaries from recognition and alignment through long-recording captions, including word-character granularity, offsets, pauses, and playback.
Understand the concept
Word timestamps attach start and end positions to words or tool-defined units for navigation and captions. They can come from recognition or alignment, and decimal precision does not establish accuracy. Units differ by language, wording needs verification, and timing alone does not produce readable caption lines.
Confirm both timing and text units
Chinese units can be characters or segmented words, differing from English boundaries. Google exposes word offsets and WhisperX uses alignment. Inspect units and structures rather than infer seconds from field appearance.
Spoken numbers and normalized strings can have different units, and missing words affect boundaries. This explains interpretation without API calls or fixed millisecond-accuracy claims.
Keep segment and global times in consistent coordinates
A chunk’s zero time is not the full recording’s start. Preserve offsets and handle duplicate overlap words. After silence removal, identify whether captions follow original or edited audio to avoid drift.
Order and duration checks catch obvious errors without proving every boundary. Listen around pauses and rapid speech. This is design without real-recording measurement; valid formatting is not accurate alignment.
Readable captions require grouping and visual checks
Word highlighting and normal captions differ. Group phrases and pauses without splitting names or speakers, with sufficient reading time. Word data is an input to layout, not finished captions.
Replay target video at boundaries and rapid changes and verify wording. Keep original and edited timestamps. No caption benchmark is reported; audiovisual checks matter beyond an exported SRT file.
Checked sources
These sources support the concepts and methods described here. Examples and test scope are labeled separately; check the version of the tools you use.