> ## Documentation Index
> Fetch the complete documentation index at: /llms.txt
> Use this file to discover all available pages before exploring further.
# Text, captions and code on screen
> Map caption tone to named caption components, and prompt per-word emphasis for composed videos.
Ask for "embedded captions, keywords highlighted in the accent color" and you get a sensible default. This page is the catalog behind that ask: the named components you can pin instead, by tone, so the highlight color and the animation are a decision, not a default.
## What caption styles do and when they trigger
Caption components are drop-in snippets that render animated on-screen text — one visual identity per component, animating per word or per line. Prompts trigger this layer when you ask for captions, subtitles, kinetic text, lyric-style words, or word-by-word titles inside a composition you're building. Describe the *energy* of the captions and the agent picks matching typography, size, and animation; name a component to lock the look.
> [!NOTE]
>
> These components are for **composed videos** — captions you author into a HyperFrames composition. To add captions to an existing **talking-head MP4**, see [captions and talking heads](/guides/captions-and-recuts.md#prompts-that-work) instead: captions set *behind* the speaker need a cutout of the subject layered over them, which the composition snippets below don't do.
## Tone → caption component
| Tone | Components |
| - | - |
| **Hype / high-energy social** | [`caption-kinetic-slam`](/catalog/components/caption-kinetic-slam), [`caption-highlight`](/catalog/components/caption-highlight), [`caption-particle-burst`](/catalog/components/caption-particle-burst), [`caption-emoji-pop`](/catalog/components/caption-emoji-pop) |
| **Clean / corporate** | [`caption-clip-wipe`](/catalog/components/caption-clip-wipe), [`caption-weight-shift`](/catalog/components/caption-weight-shift) |
| **Elegant / editorial** | [`caption-editorial-emphasis`](/catalog/components/caption-editorial-emphasis), [`caption-gradient-fill`](/catalog/components/caption-gradient-fill), [`caption-weight-shift`](/catalog/components/caption-weight-shift) |
| **Neon / nightlife / music** | [`caption-neon-glow`](/catalog/components/caption-neon-glow), [`caption-neon-accent`](/catalog/components/caption-neon-accent) |
| **Tech / cyber / glitch** | [`caption-glitch-rgb`](/catalog/components/caption-glitch-rgb), [`caption-matrix-decode`](/catalog/components/caption-matrix-decode) |
| **Karaoke / lyric / follow-along** | [`caption-pill-karaoke`](/catalog/components/caption-pill-karaoke), [`caption-highlight`](/catalog/components/caption-highlight) |
| **Textured / cinematic display type** | [`caption-texture`](/catalog/components/caption-texture), [`texture-mask-text`](/catalog/components/texture-mask-text) |
| **Depth / 3D layering** | [`caption-parallax-layers`](/catalog/components/caption-parallax-layers) |
## Text-effect components
Three [Text Effects](/catalog/components/morph-text.md) components do one focused job rather than caption a whole track:
| Component | Use when |
| - | - |
| [`caption-blend-difference`](/catalog/components/caption-blend-difference) | Text sits over busy or shifting footage and must stay legible — it auto-inverts per pixel against whatever is behind it. |
| [`morph-text`](/catalog/components/morph-text) | You want one spot to cycle through a short word list with a gooey morph ("fast / simple / yours"). |
| [`texture-mask-text`](/catalog/components/texture-mask-text) | A large display word filled with a physical texture (brick, rock, wood, metal, lava). |
## Example prompts
> 30-second vertical explainer. Add [`caption-highlight`](/catalog/components/caption-highlight) captions, TikTok-style — the visible line stays up, one word highlighted at a time.
*Rendered from the prompt above, unedited.*
> [!NOTE]
>
> Caption components ship as demos — a fixed word list, landscape sizing, an 8-second timeline. The agent re-authors the words and timings to your narration and re-sizes for your format; that's expected, not a workaround. If you want one full-screen word at a time (no visible line), that's [`caption-kinetic-slam`](/catalog/components/caption-kinetic-slam), not `caption-highlight`.
> Hype captions with [`caption-kinetic-slam`](/catalog/components/caption-kinetic-slam): one full-screen word per beat, alternating slam-in direction.
*Rendered from the prompt above with an authored 24-word line, unedited.*
> Neon music-video captions using [`caption-neon-glow`](/catalog/components/caption-neon-glow). Make brand names larger with an accent color and highlight the numbers differently.
*Rendered from the prompt above, unedited — the brand renders 1.4x in magenta, numbers in amber, distinct from the default cyan.*
> Fill the hero word "STONE" with [`texture-mask-text`](/catalog/components/texture-mask-text) using the rock texture.
## Knobs
* **Tone** picks typography, size, and animation — Hype (heavy, 72–96px, scale-pop) through Storytelling (serif, 44–56px, slow fade). See the caption-tone table in [vocabulary](/prompting/motion.md#words-for-how-motion-feels).
* **Per-word emphasis.** "Make brand names larger with accent color," "highlight numbers differently," "add bounce to emotional keywords" all work — several components key off this: [`caption-editorial-emphasis`](/catalog/components/caption-editorial-emphasis) drives a dramatic size contrast on emphasis words, [`caption-particle-burst`](/catalog/components/caption-particle-burst) fires on keywords, and the neon components carry keyword accent colors.
* **Texture variable.** [`caption-texture`](/catalog/components/caption-texture) ships lava, marble, metal, wood, concrete, and rock — name the one you want.
* **Word list.** [`morph-text`](/catalog/components/morph-text) cycles an editable list; quote the words in order.
* **Format.** Full-screen single-word styles ([`caption-kinetic-slam`](/catalog/components/caption-kinetic-slam)) and TikTok-style highlights ([`caption-highlight`](/catalog/components/caption-highlight)) are built for vertical / social framing — say "vertical" or "9:16" so sizing and safe areas match.
## Failure modes
**Don't stack a heavy effect on every word.** Caption components already animate per word; layering another emphasis on top of that competes and turns illegible. Emphasize only the keywords.
* **Avoid:** `make every word explode with particles`
* **Instead:** `caption-particle-burst, firing only on the keywords`
**Don't mix caption styles in one section.** One identity per composition (or per section) reads as designed; two competing styles read as a mistake.
* **Avoid:** `use caption-neon-glow and caption-matrix-decode together`
* **Instead:** pick one; switch styles only across a clear section break
**Don't reach for these on talking-head footage.** These are composition snippets, not the matting/occlusion pipeline — dropped onto an untouched MP4, a caption sits in front of the speaker, never behind. (The capstone thread below shows `caption-kinetic-slam` reading *behind* a subject, which is not a contradiction: that composition mattes the footage itself first, so the cutout is a separate layer the type can pass under. The limitation is about the snippet alone, not the technique.)
* **Avoid:** `add caption-highlight to my interview.mp4`
* **Instead:** `caption interview.mp4 with the words set behind the speaker` (see [captions and talking heads](/guides/captions-and-recuts.md#prompts-that-work))
**Don't match a hype style to calm content.** A high-energy caption on a corporate explainer fights the tone; let the tone table pick the identity.
* **Avoid:** `glitchy RGB captions` (on a wellness brand piece)
* **Instead:** `clean captions with caption-clip-wipe`
**Don't invent caption names.** Only the components in the [Captions](/catalog/components/caption-highlight.md) and [Text Effects](/catalog/components/morph-text.md) groups exist.
* **Avoid:** `add typewriter-bounce captions`
* **Instead:** describe the tone ("tutorial, monospace, typewriter") or name a real component
**In a real film.** This clause from a [longer HyperFrames film](/prompting/capstone.md#the-prompt-word-for-word) produced the shot below. You can lift the wording for your own video:
> THEN they speak, and the main **keywords of their own line — derived from the clip's transcription — land word-synced as huge display text BEHIND the cutout**, each keyword slamming in on its spoken moment with the subject's silhouette occluding it (the two-layer text-behind-subject plate); style the keyword type by adapting a bold **catalog caption component** (`caption-kinetic-slam` or similar) at display scale.
*That clause, rendered: the shot cut from the finished film.*
## Code on screen
A [PR video](/guides/pr-to-video.md) can name `code-diff` for a single beat. The rest of that catalog covers typing, diffing, highlighting, scrolling, and picking a terminal or editor theme by name, for the moments a walkthrough needs to slow down and let the code itself carry the scene.
Code is the one subject where the framework does the hard part for you. The [Code Animations](/catalog/blocks/code-typing.md) blocks handle syntax highlighting, caret tracking, diff coloring, and camera moves deterministically — you describe the *walkthrough*, name the block, and paste your snippet. This page is the vocabulary for doing that well; for turning a real pull request into a code-change video, see [Code and PRs](/guides/pr-to-video.md#prompts-that-work).
Everything here follows the [one-shot skeleton](/prompting/overview.md#the-shape-of-a-strong-prompt): route, spec, beats, copy, technique, negatives. The "technique" slot is where you name the block, and the "copy" slot is where your code goes — quoted exactly, because unquoted code gets paraphrased into something that won't compile.
#### Pick the motion by what the viewer should learn
Each Code Animations block answers a different "what is the viewer supposed to notice." Map the intent to the block:
| You want to show… | Name this block | Length |
| - | - | - |
| Code being written, character by character | [`code-typing`](/catalog/blocks/code-typing) | 5s |
| An edit — before → after, red/green | [`code-diff`](/catalog/blocks/code-diff) | 6s |
| One line as *the* line, everything else dim | [`code-highlight`](/catalog/blocks/code-highlight) | 5s |
| Walking a long file to a spot deep inside | [`code-scroll`](/catalog/blocks/code-scroll) | 6s |
| One snippet transforming into another | [`code-morph`](/catalog/blocks/code-morph) | 7s |
| Code on a rotating 3D slab (title-card feel) | [`code-3d-extrude`](/catalog/blocks/code-3d-extrude) | 8s |
| Code resolving out of a shader dissolve | [`code-shader-dissolve`](/catalog/blocks/code-shader-dissolve) | 7s |
| Code assembling from a particle swarm | [`code-particle-assemble`](/catalog/blocks/code-particle-assemble) | 8s |
The first four are the workhorses of a code *walkthrough* — they keep the code readable and the viewer oriented. Everything below them trades legibility for motion: they look great as an opener or a hero moment, but they trade legibility for motion, so don't ask them to carry an explanation.
> [!TIP]
>
> `code-morph` re-drives Shiki Magic Move as a paused GSAP timeline, and `code-diff` collapses removed lines and expands added lines. Both read "an edit happened" far more clearly than retyping the whole snippet with `code-typing` — reach for them when the story is *a change*, not *authoring from scratch*.
#### Prompting a typing reveal
`code-typing` reveals code character by character with a caret that tracks the frontier — no CSS animation, so it seeks cleanly. Give it the exact code and a pace; the agent re-bakes the block's syntax tokens to your snippet.
> 6-second 1920x1080 video. A dark editor types this snippet, character by character, caret tracking the frontier, then holds on the blinking cursor for the final second:
>
> ```
> export async function render(comp: Composition) {
> await comp.seek(0);
> return comp.capture();
> }
> ```
>
> Use the `code-typing` registry block. No narration, no image or media files.
*Rendered from the prompt above, unedited.*
**Quote the code as a literal block.** Prose descriptions of code get paraphrased.
* **Avoid:** `type out a function that seeks to zero and captures`
* **Instead:** paste the actual snippet in a fenced block — it renders verbatim
**Give the caret somewhere to rest.** Compositions hold their final state, so if you don't ask for a hold the last frame is a frozen full snippet — the [dead-motion tell](/prompting/motion.md).
* **Avoid:** `types the code and ends`
* **Instead:** `types the code, then holds on the blinking cursor for the final second`
#### Prompting a diff or a highlight
For "here's what changed," hand `code-diff` the before and after and let it color the delta. For "look at *this* line," give `code-highlight` the full context and name the target line.
> 6-second 1920x1080 video. Show this edit to `api.ts` as a colored diff — the removed line collapses in red, the added line expands in green:
> removed: `const res = await fetch(url)`
> added: `const res = await fetch(url, { signal })`
> Use the `code-diff` registry block. No audio.
*Rendered from the prompt above, unedited.*
> 5-second 1920x1080 video. Show a 12-line config file; a highlight band sweeps to line 7 (`timeout: 30_000`) while the surrounding lines dim. Hold with line 7 lit and the cursor blinking. Use the `code-highlight` registry block. No audio.
*Rendered from the prompt above, unedited — the agent authors plausible surrounding config lines; paste all 12 if the exact file matters.*
**Name the target line unambiguously.** The block dims context around one line — tell it which.
* **Avoid:** `highlight the important line`
* **Instead:** `highlight line 7 (timeout: 30_000)`
#### Prompting a scroll-through
`code-scroll` moves the camera down a long file to bring a target line to center and spotlights it — the block for walking real modules, not toy snippets.
> 6-second 1920x1080 video. Scroll a \~60-line source file so line 44 (`return dedupeFrames(frames)`) arrives at center and gets spotlighted; ease the scroll and let it settle without snapping. Use the `code-scroll` registry block. No audio.
*Rendered from the prompt above, unedited.*
**Ask the scroll to ease and settle, not snap.** A linear scroll that stops dead reads mechanical.
* **Avoid:** `scroll straight to the line`
* **Instead:** `ease the scroll and let it settle` — pair with the [motion grammar](/prompting/motion.md)
#### Choosing a theme by name
| Profile | Block | Profile | Block |
| - | - | - | - |
**VS Code workbench themes** — full editor chrome (activity bar, sidebar, tabs, terminal, status bar). Say "monokai" or "visual studio dark":
| Say this | Block | Say this | Block |
| - | - | - | - |
*Rendered from the prompt above, unedited.*
**Match the theme to the surface you're claiming to show.** A terminal command in a VS Code editor chrome reads wrong; a source file in Terminal.app reads wrong.
* **Avoid:** `monokai theme typing a shell command`
* **Instead:** `apple terminal homebrew profile typing a shell command`
> [!TIP]
>
> Ambiguity resolves to the closest named block. "Dark theme" is under-specified — the agent picks one of a dozen dark variants and you may not get the one you pictured. Say the theme name. This is the [specification dial](/prompting/overview.md#how-much-to-specify) applied to code: name the block when the default choice can miss.
#### Pairing with a pull request
When the code you're animating comes from a real PR, don't hand-write the beats — [point the agent at the PR](/guides/pr-to-video.md#prompts-that-work) and it reads the diff and composes `code-diff`, `code-highlight`, and `code-scroll` around the actual changed hunks. Use the blocks on this page directly when you're illustrating a concept; hand over the PR when you're narrating a specific change set.
#### Where to go next
* [Anatomy of a one-shot prompt](/prompting/overview.md#the-shape-of-a-strong-prompt) — the skeleton every prompt above uses.
* [Copy-paste examples](/prompting/examples.md) — full prompts you can adapt.
* [Code and PRs](/guides/pr-to-video.md#prompts-that-work) — turning a GitHub PR into a code-change video.
* [Ask for smooth motion and transitions](/prompting/motion.md) — the hold-and-settle rules the code blocks still need from you.
**In a real film.** This clause from a [longer HyperFrames film](/prompting/capstone.md#the-prompt-word-for-word) produced the shot below. You can lift the wording for your own video:
> **Type (0–7s).** Black-on-charcoal close-up: a cursor types real HyperFrames markup character by character — `` and a `gsap.timeline({ paused: true })` line. As the typed line completes, the text's baseline extends and becomes **the wire** — the underline literally grows into the timeline and the camera begins its dolly along it. The typed div folds into a compact clip chip (persistent element 3) that drops onto the wire. Kinetic display type states "WRITE HTML." as the travel begins.
*That clause, rendered: the shot cut from the finished film.*
## Overlays and lower thirds
On [talking-head footage](/guides/captions-and-recuts.md), lower-thirds and card overlays are designed as bespoke cards synced to that transcript. This is the reverse case: ready-made lower-third and social-overlay blocks you drop into a composition you're building from scratch, no existing footage required. Same vocabulary, pointed at a scene instead of a shot.
### 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](/catalog/blocks/lt-clean-bar.md)** — name/title identifiers for speakers, interviews, podcasts, and news.
* **[Social overlays](/catalog/blocks/x-post.md)** — 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`](/catalog/blocks/lt-clean-bar), [`lt-soft-pill`](/catalog/blocks/lt-soft-pill) |
| **High-energy / podcast / bold** | [`lt-bold-block`](/catalog/blocks/lt-bold-block), [`lt-color-block`](/catalog/blocks/lt-color-block) |
| **Cardless over footage** (interview, talking head) | [`lt-accent-underline`](/catalog/blocks/lt-accent-underline), [`lt-kicker-name`](/catalog/blocks/lt-kicker-name), [`lt-mask-reveal`](/catalog/blocks/lt-mask-reveal), [`lt-side-rule`](/catalog/blocks/lt-side-rule) |
| **Card over bright footage** | [`lt-dark-card`](/catalog/blocks/lt-dark-card) |
| **Broadcast / news** | [`lower-third-bild`](/catalog/blocks/lower-third-bild), [`news-ticker`](/catalog/blocks/news-ticker) |
| **Two-part wipe (name + role)** | [`lt-stack-bars`](/catalog/blocks/lt-stack-bars) |
> [!TIP]
>
> 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`](/catalog/blocks/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`](/catalog/blocks/x-post) |
| A Reddit post card with upvotes and comments | [`reddit-post`](/catalog/blocks/reddit-post) |
| A Spotify now-playing card with album art and progress | [`spotify-card`](/catalog/blocks/spotify-card) |
| A macOS notification banner | [`macos-notification`](/catalog/blocks/macos-notification) |
| An Instagram follow prompt | [`instagram-follow`](/catalog/blocks/instagram-follow) |
| A TikTok follow prompt | [`tiktok-follow`](/catalog/blocks/tiktok-follow) |
| A YouTube subscribe lower third | [`yt-lower-third`](/catalog/blocks/yt-lower-third) |
### Example prompts
Quote the exact copy — unquoted names and titles get paraphrased (see [anatomy](/prompting/overview.md#the-shape-of-a-strong-prompt)).
> Add a lower third at 0:03 for 5 seconds, on a track above the footage, with [`lt-clean-bar`](/catalog/blocks/lt-clean-bar). Name: "Dana Ríos". Title: "Head of Design".
*Rendered from the prompt above over stand-in footage, unedited.*
> [!NOTE]
>
> 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`](/catalog/blocks/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`](/catalog/blocks/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.*
> Transparent overlay only — a [`spotify-card`](/catalog/blocks/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](/guides/rendering.md#ask-the-agent-for-the-right-output).
### Common mistakes
**Don't leave the copy unquoted.** Unquoted names and titles get paraphrased; quoted text renders verbatim.
* **Avoid:** `add a lower third with the speaker's name and role`
* **Instead:** `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.
* **Avoid:** `put a lower third somewhere in the intro`
* **Instead:** `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.
* **Avoid:** `add the tweet card to the video` (ambiguous layering)
* **Instead:** `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.
* **Avoid:** `pull my actual Spotify page`
* **Instead:** `spotify-card: track "Midnight City", artist "M83"`
**Don't invent overlay names.** Only the blocks in the [Social Overlays](/catalog/blocks/x-post.md) and [Lower Thirds](/catalog/blocks/lt-clean-bar.md) groups exist.
* **Avoid:** `add a linkedin-post overlay`
* **Instead:** pick a real block, or describe the card and let the agent build a custom one in a freeform composition
**In a real film.** This clause from a [longer HyperFrames film](/prompting/capstone.md#the-prompt-word-for-word) produced the shot below. You can lift the wording for your own video:
> \[…] as the camera arrives and BEFORE the person speaks, the framework mattes the footage — **the background peels away via background removal**, sliding off along the travel direction and leaving the cutout standing alone on the brand ground. \[…] A designed lower-third chip renders behind the subject.
*That clause, rendered: the shot cut from the finished film.*