What it means
A voiceover is recorded speech used with a video or other presentation. It can explain a scene, connect evidence or carry a story without requiring the speaker to appear in the picture. It is a separate production element from background music.
Script, recording and captions are different artifacts
The script is a plan. The recording is a performance with actual durations and pauses. Captions are timed text associated with that performance. Recording software such as Premiere can place a voiceover onto an audio track; a text file alone is not that recording.
Estimate first, then measure
Use the narration estimator to explore a range before recording. Adjust its assumptions from your own read-through. After recording, use the real audio duration and listen for wording changes before preparing captions.
A useful production record
Keep the script revision, voice recording and chosen caption revision identifiable. If the narration changes, review the corresponding visual plan and caption timing. A claim about a sentence's timing should refer to the audio that was actually used.
The free estimator does not synthesize or clone a voice. It calculates a text-based estimate that you can download and review.