Description is spoken in the gaps between dialogue

What it is

Standard audio description is spoken in the breaths between dialogue, not on top of the line. Two foreground voices on one ear smash both the line and the description. When the gaps run out, the problem is not “read faster.” It is that this sentence has no legal slot on this clock.

Why it happens

Hearing treats one stretch of language as foreground. Description and dialogue are both sentences; stacking them is a cocktail party, and the listener loses both. The professional move is to mark dialogue in and out, and to speak only in silence, action sound, or other non-speech gaps. After the action, before the next line, is the usual legal slot.

Wall-to-wall talk leaves no room in a standard mix. The way out is extended description: pause the picture, finish the sentence, resume. That changes duration and needs a player that can pause. Live almost never gets that pause; a missing gap means dropping that description, not talking over the person already speaking. When music is the foreground, description also steers around the theme, or two pitched voices fight.

Studying it

On the timeline, measure overlap duration: how many seconds the description voicing shares with dialogue voicing. Then run comprehension comparing description laid on dialogue against description confined to gaps.

Independent variables: insertion strategy (overlap / gap / pause-and-extend), dialogue density. Dependent variables: dialogue intelligibility and description intelligibility, scored separately. A single “overall understanding” number hides whichever stream was stepped on.

Overlap you can see on a waveform is more operational than a questionnaire item about “feeling messy.”

Where it stops holding

Extended description is allowed to pause, so the rule becomes “you may stop,” not “never overlap.” If the listener can ride the description-track fader, mild overlap can sometimes be pushed down — that is not a licence to mix on top of dialogue on purpose. Fast languages with short breaths need fewer words per action, or an earlier decision to extend. Live commentary and sports almost cannot pause; incomplete coverage is expected. It is not an excuse to speak into the commentator’s sentence.

Applying it

• Spot the dialogue first. Write description only in the gaps. If overlap exceeds two or three words, rewrite.
• Visual facts that must be said when the gap is gone belong on an extended track or a recut, not on a faster reading.
• How to check: inspect the waveform; description and dialogue should not share long stretches. Ask a blind reviewer whether any line was stepped on. Each stepped-on line is a slot error, not a wording error.

Related

• Same group: J4.03.1 Audio description supplies the visual facts dialogue never says · J4.03.3 Gaps left at the script stage cost less than describing afterwards
• Nearby: J1.01 Four Principles · D2.12 Equivalence between sound and captions
• Search terms: AD dialogue gaps · extended audio description · standard AD