- name
- hunk-launch-video
- description
- Produces Hunk videos by driving the real TUI headlessly in a PTY, compositing captioned 1080p frames in Chromium, and encoding with ffmpeg. Use for feature demos, workflow explainers, announcements, launch videos, and full-release roundups.
# Hunk video pipeline
Source-checkout only: the pipeline lives in `scripts/launch-video/`, which never ships to npm.
It can be used for pull-request demos as well as maintainer release videos. Unix-only — the
capture scripts exec `/bin/bash`.
Generates product videos where every terminal frame is the real Hunk TUI —
no screen recording, no mockups. Three stages:
```text
capture.ts (bun) drive Hunk over a PTY, snap styled keyframes to PNG
compose.mjs (node + Playwright) render each PNG on a 1920x1080 HTML stage in Chromium
ffmpeg encode the composited PNGs at 30fps to mp4/webm
```
Playwright controls headless Chromium: for each planned frame it loads the
terminal PNG onto the HTML stage, applies the window chrome, cards, captions,
and transition state, then screenshots the completed stage back to PNG. ffmpeg
sequences those composited screenshots into the final videos.
The generic machinery (PTY driving, keyframe rendering, storyboard planning,
Chromium compositing, the stage template) is the `@hunk/term-video` workspace
package in `packages/term-video/`; `scripts/launch-video/` holds only Hunk's
scenes, captions, and cards on top of it.
## Choosing a recipe
The pipeline is not release-specific. Choose the editorial scope, then use the
same capture → composite → encode stages:
- **Single feature:** a short demonstration of one capability or workflow. Use
the single-feature recipe below and capture only the required scene.
- **Full release:** a multi-feature roundup based on a release's changelog or
highlights. Use the full-release recipe and update the canonical storyboard.
- **Custom video:** author any set of scenes and `SHOTS` for tutorials,
comparisons, announcements, or workflow explainers; follow the scene and
storyboard rules below.
## Creating a video
Expect ~3–6 min for capture and ~2–4 min for compose — run both with a long
timeout (or in the background); each logs per-snap / per-shot progress.
`compose.mjs` needs node ≥ 18 on PATH (bun alone is not enough).
```sh
# 0. dependencies (tuistory is a devDependency; ghostty-opentui arrives transitively)
bun install # if a postinstall hook fails in a sandbox, retry with --ignore-scripts
# 1. capture the current storyboard's default scenes. Output defaults to
# <repo>/.video-work/ regardless of cwd (pass a path argument to override),
# but the PROCESS must run from the repo root — see gotchas.
bun run scripts/launch-video/capture.ts
# 2. one-time portable compositor setup. Playwright installs a Chromium build
# that exactly matches its browser driver (see gotchas to reuse a system or
# sandbox browser instead).
printf '{"name":"hunk-video-work","private":true}\n' > .video-work/package.json
cd .video-work
bun add playwright playwright-core
bunx playwright install chromium
cd ..
# 3. composite the storyboard
node scripts/launch-video/compose.mjs .video-work
# 4. encode
cd .video-work
ffmpeg -y -f concat -safe 0 -i concat.txt -vf "format=yuv420p" -r 30 \
-c:v libx264 -preset slow -crf 18 -movflags +faststart launch.mp4
ffmpeg -y -f concat -safe 0 -i concat.txt -vf "format=yuv420p" -r 30 \
-c:v libvpx-vp9 -b:v 0 -crf 32 -row-mt 1 launch.webm
```
Override the default scene set to iterate on one or more scenes:
```sh
SCENES=review bun run scripts/launch-video/capture.ts # comma-separated scene names
```
Scene names are the `wants("...")` guards in `capture.ts`'s `main()`. `SCENES=`
replaces the canonical default scene set; `compose.mjs` preflights that every
frame its `SHOTS` table references exists in `frames/` and fails fast listing
any missing ones, so a full composite still needs every referenced scene
captured at least once.
## Single-feature recipe
For a short test, demo, or one-feature announcement, capture and composite only
the scene for that feature:
1. Pick one user-visible capability and find its scene name in the
`wants("...")` guards. If it does not have a scene, author one using the
guidance below. Capture only that scene:
```sh
SCENES=review bun run scripts/launch-video/capture.ts
```
2. Make a scratch compositor beside the canonical one so its imports and
repo-relative paths continue to work:
```sh
cp scripts/launch-video/compose.mjs scripts/launch-video/compose-one-feature.mjs
```
3. In the scratch copy, trim `SHOTS` to an opening card, only the selected
feature's frames, and an outro card. Rewrite those cards and captions for
the scoped cut. Sequence lengths must still match the captured frame names.
4. Composite into the same work directory, then run the normal ffmpeg commands
with descriptive output names:
```sh
node scripts/launch-video/compose-one-feature.mjs .video-work
cd .video-work
ffmpeg -y -f concat -safe 0 -i concat.txt -vf "format=yuv420p" -r 30 \
-c:v libx264 -preset slow -crf 18 -movflags +faststart hunk-feature-demo.mp4
ffmpeg -y -f concat -safe 0 -i concat.txt -vf "format=yuv420p" -r 30 \
-c:v libvpx-vp9 -b:v 0 -crf 32 -row-mt 1 hunk-feature-demo.webm
cd ..
rm scripts/launch-video/compose-one-feature.mjs
```
Keep the scratch compositor uncommitted. The canonical `compose.mjs` remains
the checked-in reference storyboard. If you added a capture scene only to make
PR evidence, revert that scene after encoding; retain it only when it is useful
checked-in demo coverage and belongs to the submitted change.
## Full-release recipe
1. Read the release section in `CHANGELOG.md`. If it has a hand-written
**Highlights** list (0.18.0 has one; Changesets does not generate them), use
that list as the storyboard. Otherwise distill 4–6 user-visible headlines
from the Minor Changes — per-PR entries are too granular to shoot — and
confirm the shortlist with the user before capturing.
2. Rewrite the canonical storyboard's editorial surface (next section), adding
or adjusting capture scenes as needed (see "Authoring scenes").
3. Set `SCENES` to every scene referenced by the full storyboard, capture and
composite it, then encode both formats using the main workflow above.
4. Verify the complete cut (see "Verification") and deliver both files. When `hunk-release` invoked this workflow, return the approved MP4 and WebM to that skill for versioned naming and GitHub user-attachment embedding; do not upload or edit the public release without its confirmation gate.
## Per-video editorial surface
The capture machinery is reusable, but the storyboard is editorial content for
one video. Rewrite it to match the video's scope. The checked-in reference is a
single-feature Git-history video, not a frozen release artifact:
- `compose.mjs`: the whole `SHOTS` table; opening, feature, and outro cards;
every caption; camera targets; and callout rectangles. A `NEW` badge is a
claim about the video at hand, so drop or move it as features age.
- `capture.ts`: `SCENES` selects from a reusable scene library. With no
override it captures only the current storyboard's default scene; update
that default whenever the canonical storyboard changes. Hunk-side glue
(`launchHunk`, `launchHunkShell`, demo repositories, and the keyboard probe)
remains reusable.
Reusable machinery lives in `@hunk/term-video` (`packages/term-video/`) —
extend it there, don't fork it into the scripts: `createKeyframer`,
`launchApp`/`launchShell`, `createCommandWrapper`, `typeCommand`,
`ensureKeyboardIsLive`, `makeSceneFilter` (`src/capture.ts`); the unit-tested
storyboard planner with the caption/timing semantics (`src/plan.mjs`);
`composeStoryboard` with font/Chromium resolution and the missing-keyframe
preflight (`src/compose.mjs`); and the stage template (`src/stage.html`).
## Environment gotchas
Sandbox-specific bullets are marked; each cost real debugging time.
- **Run `capture.ts` with bun from the repo root.** tuistory uses subpath
self-imports (`tuistory/pty`) that only resolve inside this repo's
`node_modules`; running the script from elsewhere resolves tuistory from
bun's global cache and crashes. (Output location is unaffected — it defaults
to `<repo>/.video-work/` via `import.meta.url`.)
- **ghostty-opentui is a transitive dep** (via tuistory) with an exports map:
import `"ghostty-opentui/image"` (not `.../dist/image.js`), resolved
relative to tuistory — `@hunk/term-video/capture`'s `createKeyframer` does
the `Bun.resolveSync` dance.
- **Playwright must match the Chromium it drives.** The portable setup above
installs `playwright` and `playwright-core` together, then downloads their
matching Chromium build. It works on macOS and Linux and is preferred when
bandwidth and browser downloads are available; leave `CHROMIUM_PATH` unset
so Playwright uses that managed browser. On Linux, if Chromium reports
missing system libraries, run `bunx playwright install-deps chromium` (it
may require sudo) before retrying.
To reuse an existing system, CI, or sandbox Chromium instead, install the
`playwright-core` version provided by that environment and set its executable
explicitly:
```sh
cd .video-work
bun add playwright-core@<matching-version>
cd ..
CHROMIUM_PATH=/path/to/chromium node scripts/launch-video/compose.mjs .video-work
```
Common executable locations include `$(command -v chromium)` or
`$(command -v google-chrome)` on Linux and
`/Applications/Google Chrome.app/Contents/MacOS/Google Chrome` on macOS.
In an environment with a preinstalled Playwright toolchain, read that
toolchain's `package.json` to get the exact driver version. For example, the
Anthropic sandbox exposes it through `/opt/pw-browsers/.links/*`:
```sh
cat "$(cat /opt/pw-browsers/.links/* | head -1)/package.json" | grep '"version"'
# e.g. "1.56.1" -> bun add playwright-core@1.56.1
```
`compose.mjs` picks its browser as `$CHROMIUM_PATH`, then
`/opt/pw-browsers/chromium` when present, then Playwright's managed browser.
If a dependency update leaves Playwright asking for an uninstalled browser
revision, either rerun `bunx playwright install chromium` in `.video-work/`
or set `CHROMIUM_PATH` to a known system browser such as `/usr/bin/chromium`.
- **Give `.video-work/` its own `package.json` before `bun add`.** Without
one, bun walks up and installs into the repo's `package.json` — revert with
`git checkout package.json bun.lock` if that happens.
- **Chromium needs `--allow-file-access-from-files`** (already in
`compose.mjs`): the stage samples each keyframe through a canvas to
color-match the window background, and file:// images taint the canvas
without it.
- **mp4 needs an ffmpeg with libx264.** Sandbox: `apt-get install ffmpeg`
(run `apt-get update` first if packages 404). macOS: `brew install ffmpeg`.
Verify `ffmpeg -encoders | grep -E 'libx264|libvpx-vp9'` shows both before
encoding — playwright's bundled `ffmpeg-*/ffmpeg-linux` only does VP8/WebM
and cannot produce the mp4.
- **Caption font**: JetBrains Mono ships inside ghostty-opentui;
`findCaptionFont` in `packages/term-video/src/compose.mjs` searches bun's
isolated layout (`node_modules/.bun/node_modules/…`) then a hoisted
`node_modules/…`. If it still throws `caption font not found`, locate the
file with `find node_modules -name jetbrains-mono-nerd.ttf` and pass it as
`fontPath` to `composeStoryboard`.
## Authoring scenes (capture.ts)
- Shared geometry is 140x32 cells rendered at fontSize 16 / dpr 2 → 2688x1536
PNGs. Keep every scene at this size so all frames fit one window.
- Keep time-sensitive fixtures recent and timezone-stable. The canonical
history scene derives commit dates from the current UTC day and launches
Hunk with `TZ=UTC`, so day groups and relative-age labels remain useful on
future runs. Preserve that policy in custom history scenes.
- Helpers: `createDemoRepo()` and `launchHunkShell()` are hunk-side glue in
the script (git repo built from `examples/2-mini-app-refactor`; interactive
bash with a real `hunk` command on PATH and a clean `❯` prompt); `snap`,
`typeCommand`, `launchApp`/`launchShell`, and `createCommandWrapper` come
from `@hunk/term-video/capture`.
- Always `waitForText` on scene-specific content before the first snap, and
call `ensureKeyboardIsLive()` before scripted keypresses — the first key
after startup can be dropped (real race, the helper toggles `?` to prove
keys land).
- **Animation = one snap per keypress.** Cursor walks and typing effects are
just every `j`/`k`/character captured as its own frame and played back at
0.2–0.3s per frame. Prefer this over sparse keyframes: three stills read as
a slideshow, per-press frames read as motion.
- `renderTerminalToImage` auto-trims trailing blank rows, so short outputs
(CLI scenes) produce short PNGs — the stage handles this by sampling the
image's bottom-left pixel and painting the window body to match.
- `manifest.json` is a capture-side inventory of the _current run_ only;
`compose.mjs` ignores it (frames resolve by name from `SHOTS`), and after a
`SCENES=` run it is partial while `frames/` stays cumulative.
- Demo content that must exist: STML notes come from
`examples/9-agent-markup-notes` (launch with `--experimental`), extension
scenes from `examples/extensions/` loaded via `--extension <path>` (explicit
paths skip the repo trust prompt). The pager pipe is `git diff | hunk pager`
— bare `hunk` on piped stdin prints help. Sidebar toggle is `s`; comment
draft is `c`, save with Ctrl+S (`\x13`).
## Storyboard model (compose.mjs)
- `SHOTS` is the whole edit: one entry per shot, `dur` in seconds, played as
unique frames + per-frame durations in an ffmpeg concat list (holds cost one
frame, so runtime is dominated by transitions, not length).
- `capKey` is caption identity: the caption slides in only when `capKey`
changes, and continuation shots that share a `capKey` without restating
`caption` keep the previous caption on screen. Sequences (walks, typing) are
generated with `Array.from` spreads.
- **Sequence lengths must match capture loop bounds**: the history capture's
`selected = 2..4` loop produces `history-range-2..4`, consumed by a
three-entry `Array.from` spread in `SHOTS`. Change one side and the other
breaks — the preflight check names any frame that's missing.
- `enter: true` fades/scales the surface in — use it for cards and the first
terminal shot only.
- Terminal shots may set normalized `camera: { x, y, scale }` targets and
`highlight: { x, y, width, height, label? }` rectangles. `motion` controls
the transition length in seconds. The planner interpolates camera changes
and outline geometry, while the stage keeps the camera inside the captured
image and paints an animated glow around the source-aligned region. Set the
same `cameraKey` or `highlightKey` on related keyframes when their normalized
coordinates share one capture geometry. Cross-image camera changes cut to
their target unless `cameraKey` explicitly permits a pan, and outlines never
leak across unrelated images.
- Caption HTML vocabulary: `<span class="badge">NEW</span>` amber pill,
`<span class="hl">` amber highlight, `<span class="dim">` muted. Cards use
`badge` / `h1`/`h2` / `sub` / `cmds`+`cmd` / `foot` classes from
`packages/term-video/src/stage.html`.
- Target pacing: money shots hold 3–4s, context shots 2–3s, typing/walk frames
0.2–0.6s; keep the total near 60s.
## Camera and callout composition
Treat `camera` and `highlight` as one composition. Both use normalized source
coordinates, but the stage projects highlights through the active camera. A
rectangle that fits within the source can still lose an edge after zooming.
Use this framing process:
1. Start with a full-frame establishing shot, then pan or zoom to one readable
subject. Use `motion` around 0.7–0.9s for a deliberate move rather than a
cut disguised as animation.
2. Fit the target plus its outline inside the camera viewport. Leave about 1%
of the visible width on each side and at least one terminal row above and
below the meaningful content. If that does not fit, reduce `camera.scale`.
3. Put outline edges in actual blank rows. Mathematical padding can move a
border onto a neighboring date heading, status row, or metadata line.
4. Check both sides of the capture. A zoom that preserves left-aligned subjects
can still crop hashes, authors, or status text aligned to the right.
5. Give irregular states explicit rectangles. A growing commit range that
crosses day separators should use measured per-keyframe heights instead of
assuming every added item occupies the same vertical distance.
6. Share `cameraKey` or `highlightKey` only when captures use the same source
geometry. This allows pans and outline morphs across related captures;
unrelated keyframes cut or fade separately.
The outline should direct attention, not become the subject. Use one callout at
a time, keep labels short, and remove the outline once the viewer has enough
context to follow the interaction unaided.
## Command and output legibility
Terminal commands and their results must be readable at normal playback size.
Never rely on a full-width terminal prompt or output region as the only way the
viewer can understand a command scene; text that looks acceptable in a 1080p
source frame is often illegible in an embedded player or social feed.
Use this default treatment:
1. **Present the exact command in large type.** The easiest treatment is a
`cmd` card or an oversized editorial callout immediately before the real
terminal result. A typing animation may remain for motion, but it does not
replace the large command treatment.
2. **Zoom the real output.** Crop or scale the captured terminal frame around
the meaningful result so both the command and the important output lines
are comfortably readable. A brief full-window establishing shot is fine,
but the result's main hold must use the focused view.
3. **Keep the evidence real.** Never fabricate terminal output. Large command
text may reproduce the exact command as an editorial overlay; any enlarged
output must come from the captured PTY frame. If reusable crop/zoom controls
are missing, add them to `@hunk/term-video` rather than baking one-off image
edits into a storyboard.
4. **Trim before shrinking.** Prefer fewer relevant lines and a tighter crop
over fitting a long transcript into the frame. Split a workflow across
multiple focused shots when one crop cannot keep every important line
legible.
Treat command legibility as a release gate: if the command or its result cannot
be read when the 1920x1080 video is displayed at 50% size, revise the shot.
## Content accuracy (learned the hard way)
- **Verify install commands against reality**, not the README: check
`npm view hunkdiff dist-tags`. A prerelease needs `npm i -g hunkdiff@beta`;
`brew install hunk` only serves stable (homebrew-core Autobump, lags npm) —
omit brew on prerelease cards.
- **Label demo extensions as examples.** The triage board, CSS palette, and
semver views are `examples/extensions/`, not shipped features — caption them
with a dimmed `example:` prefix. The real features are the APIs (sidebars,
file views, commands, dialogs).
- Window titles are decorative but must not lie: the shell scenes run bash,
so keep their titles generic (`shell — …`) rather than naming a shell the
capture doesn't launch.
- STML requires `--experimental`; say so on the outro card.
- The video is silent — never imply audio in the video or its announcement copy.
## Verification and delivery
- Eyeball keyframes in `.video-work/frames/` (Read renders PNGs) after
capture — especially new scenes — before compositing.
- Inspect every command scene at 50% display size. Confirm the exact command is
shown in large type and the meaningful real output is zoomed tightly enough
to read; a readable caption does not compensate for unreadable terminal text.
- Composite and encode the MP4 first. Inspect it before spending time on the
slower VP9/WebM encode; produce both final formats only after the visual pass.
- After encoding, return to the repository root, set `VIDEO` to the produced
MP4, and inspect a settled frame for each callout, a mid-animation point,
each new scene, and the outro:
```sh
VIDEO=.video-work/hunk-feature-demo.mp4 # or .video-work/launch.mp4
ffmpeg -y -ss 2 -i "$VIDEO" -frames:v 1 -update 1 .video-work/check.png
ffprobe -v error -show_entries format=duration,size \
View on GitHub