A silent-looking gap may not be free
Before recording description, mark the visual information that needs explanation and the audio information already occupying each interval. A pause in dialogue can still carry essential sound or music that the production wants the reader to hear.
For an invented demonstration, a brief pause contains both a visible adjustment and a confirming tone. Filling the entire interval with narration may explain the adjustment while hiding the confirmation. Review the combined meaning rather than treating every dialogue gap as spare time.
Choose the production method early
W3C WAI describes integrated description and separate described versions, including approaches when descriptions do not fit existing spaces. A new owned production may be able to build the explanation naturally into the speaker's script. An existing finished edit may need another treatment.
Keep a gap ledger with required information, available interval and competing sound. Have the description writer and editor review it before voice recording. This can expose an impossible script duration before an otherwise polished narration has been commissioned.
Review the final mix
Listen to the complete described version and compare it with the intended visual information. Check the start and end of every added phrase for competition with dialogue or essential sound. A narration-only file cannot show whether the final mix communicates both.
If more time is needed, plan the separate version and its picture changes deliberately, then update captions and transcript references for that version. Do not simply speed the narration until it fits. This is a production planning workflow, not a completed mix assessment or a conformance claim.
Questions answered
Is every pause in dialogue available for description?
No. Essential sound and other programme information may already use that interval.
What if the needed explanation will not fit?
Review another production approach, such as integrated description or a separately edited described version, rather than forcing unreadable timing.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.