voice-over

US /ˈvɔɪs.oʊ.vər/
UK /ˈvɔɪs.oʊ.vər/
"voice-over" picture
1.

旁白, 画外音

a piece of narration in a movie or broadcast, not accompanied by an image of the speaker.

:
The documentary used a powerful voice-over to tell the story.
这部纪录片用有力的旁白讲述了故事。
She recorded the voice-over for the commercial.
她为广告录制了旁白