Files
Miguel Ángel b3c43e2480 feat(cli): add normalize-audio to match one clip's loudness to another (#3306)
* feat(cli): add normalize-audio to match one clip's loudness to another

Measures two authored `<audio>` clips with FFmpeg's integrated EBU R128
loudness and writes the target's matching `data-volume`, leaving the
reference untouched.

The measurement is bounded to the window the composition actually plays.
`data-end` bounds a clip's timeline window just as `data-duration` does, and
`-ss`/`-t` belong before `-i`: after it they bound the OUTPUT, and with
`-f null` there is none, so ebur128 keeps integrating past the clip. On a
fixture whose played window is -61.8 LUFS inside a file that measures -27.9
whole, either mistake reports a loudness the composition never plays and
"corrects" an already-matched clip by tens of dB.

Two EBU R128 passes run between reading the composition and writing it, each
bounded only by a two-minute timeout, and the skill docs tell agents to keep
Studio open meanwhile — so the attribute patch is re-applied to a fresh read
and written through a temp file and a rename.

Under `--json` the failures are documents too: an agent doing
`JSON.parse(stdout)` on a bare error line throws. A pair needing more than the
+12 dB ceiling has a source-file problem rather than a mixer one — mixer gain
raises the noise floor with the signal — so the refusal names the remedy.

* fix(cli): validate --tolerance before paying for the measurement

Each EBU R128 pass is bounded at 120s and normalize-audio runs two, so
parsing the argument afterwards made a typo'd --tolerance cost both of them
before failing on something that was wrong from the start.

Not pinned by a test: the ordering is internal to the command and neither it
nor the parser is exported, so covering it would mean restructuring for a spy
rather than asserting the behaviour.

* docs(cli): restore the blank line between the preview and normalize-audio sections

Lost when I resolved the rebase conflict against the background-preview docs
by hand instead of letting the formatter near it. oxfmt --check failed on the
one file, which fails Preflight — and because preview-parity needs Preflight it
skipped, and the preview-regression gate fails closed on a skip, so a missing
newline read as a preview defect.

The quieter half: the same needs chain meant the required Test context was
never created at that head. Not failing — absent, so there was no test signal
at all on the PR.
2026-08-19 17:36:10 -04:00

3.6 KiB

hyperframes

CLI for creating, previewing, and rendering HTML video compositions.

Install

npm install -g hyperframes

Or use directly with npx:

npx hyperframes <command>

Requirements: Node.js >= 22, FFmpeg

Commands

init

Scaffold a new Hyperframes project from a template:

npx hyperframes init my-video
cd my-video

preview

Start the live preview studio in your browser:

npx hyperframes preview
# Studio: http://localhost:3002/#project/my-video
# Server: http://localhost:3002

npx hyperframes preview --port 4567

In an interactive terminal, the preview stays attached until you press Ctrl+C. In a non-interactive shell such as a coding-agent session, the same command starts a managed preview that survives after the command returns. Use --background or --foreground to choose explicitly, and manage persistent previews with --status, --stop, --list, and --kill-all. Add --json to managed lifecycle commands for machine-readable output. --foreground --json prints the ready-session envelope once, then remains attached until stopped.

normalize-audio

Measure two local authored audio clips with integrated LUFS and match the target to the unchanged reference. The command is a dry run unless --write is passed:

npx hyperframes normalize-audio --reference target-audio --target user-audio
npx hyperframes normalize-audio --reference target-audio --target user-audio --write

It updates only the target element's data-volume and refuses unsafe boosts that exceed Studio's +12 dB ceiling or would clip.

render

Render a composition to MP4. Run from the project directory; the positional argument is the project directory (not a file), so render the project's index.html directly, or point at a specific composition file with -c:

npx hyperframes render -o output.mp4
npx hyperframes render -c ./my-composition.html -o output.mp4

lint

Validate your Hyperframes HTML:

npx hyperframes lint ./my-composition
npx hyperframes lint ./my-composition --json      # JSON output for CI/tooling
npx hyperframes lint ./my-composition --verbose   # Include info-level findings

By default only errors and warnings are shown. Use --verbose to also display informational findings (e.g., external script dependency notices). Use --json for machine-readable output with errorCount, warningCount, infoCount, and a findings array.

compositions

List compositions found in the current project:

npx hyperframes compositions

benchmark

Run rendering benchmarks:

npx hyperframes benchmark ./my-composition.html

doctor

Check your environment for required dependencies (Chrome, FFmpeg, Node.js):

npx hyperframes doctor

browser

Manage the bundled Chrome/Chromium installation:

npx hyperframes browser

info

Print version and environment info:

npx hyperframes info

docs

Open the documentation in your browser:

npx hyperframes docs

upgrade

Check for updates and show upgrade instructions:

npx hyperframes upgrade
npx hyperframes upgrade --check --json  # machine-readable for agents

Documentation

Full documentation: hyperframes.heygen.com/packages/cli