What overlays do and when they trigger
Overlays are timed blocks that sit on top of your footage or scene — a lower third that names a speaker, a broadcast ticker, or a replica social-media card. Because each is a timed clip, prompts trigger this layer when you ask to add something at a moment: “add a lower third at 0:03 with the name and title,” “show an animated tweet during the intro,” “put a Spotify now-playing card in the corner.” Give the timestamp, the copy, and the tone; the agent places the block on a track above the footage.
Two groups:
- Lower thirds — name/title identifiers for speakers, interviews, podcasts, and news.
- Social overlays — animated replicas of platform UI (posts, cards, notifications, follow prompts).
Brand tone → lower third
Lower thirds split into cards (a filled shape behind the text) and cardless (text with a rule or sweep, designed to overlay live footage without boxing it in).
| Tone | Blocks |
|---|
| Minimal / clean / corporate | lt-clean-bar, lt-soft-pill |
| High-energy / podcast / bold | lt-bold-block, lt-color-block |
| Cardless over footage (interview, talking head) | lt-accent-underline, lt-kicker-name, lt-mask-reveal, lt-side-rule |
| Card over bright footage | lt-dark-card |
| Broadcast / news | lower-third-bild, news-ticker |
| Two-part wipe (name + role) | lt-stack-bars |
Over live footage, prefer a cardless lower third — they’re text-shadowed for legibility without a box that fights the shot. Use a card (lt-dark-card charcoal for bright scenes) when the background is too busy for cardless text to read. Use → social overlay
Each social overlay is a self-contained animated card with editable placeholder content.
| You want | Block |
|---|
| An animated tweet / X post with engagement metrics | x-post |
| A Reddit post card with upvotes and comments | reddit-post |
| A Spotify now-playing card with album art and progress | spotify-card |
| A macOS notification banner | macos-notification |
| An Instagram follow prompt | instagram-follow |
| A TikTok follow prompt | tiktok-follow |
| A YouTube subscribe lower third | yt-lower-third |
Example prompts
Quote the exact copy — unquoted names and titles get paraphrased (see anatomy).
Add a lower third at 0:03 for 5 seconds, on a track above the footage, with lt-clean-bar. Name: “Dana Ríos”. Title: “Head of Design”.
Rendered from the prompt above over stand-in footage, unedited.
Give a lower third at least the block’s own timeline length (most run ~5 seconds including their designed exit) — a shorter window hard-cuts the block before its settle-out animation plays.
Podcast clip. Bring in lt-bold-block when the guest starts talking, holding 5 seconds — name “MARCUS LEE”, tag “GUEST” — brand accent #FF5A1F.
During the intro, show an x-post card with the quote “we shipped it in a weekend” and 12.4K likes, then slide it out before the demo.
Rendered from the prompt above over stand-in scenes, unedited — the card’s built-in like-tap ticks 12.4K → 12.5K.
/motion-graphics Transparent overlay only — a spotify-card now-playing widget animating in, bottom-left. Export as transparent WebM so I can drop it over footage in my editor.
MP4 preview of the transparent WebM over a checkerboard — the delivered file carries real VP9 alpha (verified via ALPHA_MODE + alphaextract).
Knobs
- Timing. “at 0:03,” “for 4 seconds,” “slide it out before the demo” set the block’s start and duration — an overlay is a timed clip, so it needs both.
- Copy. Quote every editable field: name, title, handle, headline, metrics, ticker text. The blocks ship with placeholder content you replace.
- Track placement. Overlays go on a track above the footage so they composite on top; say “over the footage” if you’re layering onto an existing clip.
- Brand accent. Give a hex or brand color — most lower thirds carry an accent bar, tab, or block that takes it.
- Card vs cardless. State it when it matters, or let the tone table decide.
- Transparent output. For use in an external NLE, render the overlay on its own as a transparent WebM — see rendering and output.
Failure modes
Don’t leave the copy unquoted. Unquoted names and titles get paraphrased; quoted text renders verbatim.
- ❌
add a lower third with the speaker's name and role
- ✅
lt-clean-bar — name: "Dana Ríos", title: "Head of Design"
Don’t omit the timestamp. An overlay is a timed clip; without a start (and ideally a duration) the agent has to guess when it appears and how long it holds.
- ❌
put a lower third somewhere in the intro
- ✅
lower third at 0:03, holding 4 seconds
Don’t let the overlay render behind the footage. It has to sit on a track above the clip, or the video covers it.
- ❌
add the tweet card to the video (ambiguous layering)
- ✅
x-post card on a track above the footage, top-right
Don’t over-spec real account data. These are stylized replicas with editable placeholders — provide the copy you want shown, not a live URL to scrape.
- ❌
pull my actual Spotify page
- ✅
spotify-card: track "Midnight City", artist "M83"
Don’t invent overlay names. Only the blocks in the Social Overlays and Lower Thirds groups exist.
- ❌
add a linkedin-post overlay
- ✅ pick a real block, or describe the card and let the agent build a custom one in a freeform composition
