* fix(cli): keep a live preview's ownership record and stop past a bad one A missed liveness probe is not proof the preview is gone — a server blocked on a Puppeteer capture answers nothing for a second or two — but any miss retired the session record, and the record carries the only PID-reuse guard `--stop` has. Reproduced by SIGSTOPping a managed preview and running `--status`: the record was deleted and never came back, leaving every later stop to fall through to an unauthenticated port scan with no ownership proof at all. Only a wrapper process that is provably gone now retires a record. That record gains a process-birth token so a recycled PID reads as a different process, and it is written through a temp file and renamed — every reader deletes it when it fails to parse, so a torn read would otherwise destroy a live server's proof of ownership. Two failure-propagation bugs in the stop path: `--kill-all` collected the first unprovable record's exception and abandoned every server after it, so they were left running AND unreported; and a replacement refused to launch when the server it was replacing had already exited on its own, which is the goal state rather than a failure. `--list` now shows managed sessions ahead of whatever else answers the scan. * fix(cli): keep a record whose identity lookup gave no answer, not a different one Review blocker. The keep-alive path this PR adds could still retire a LIVE record — through a different door than the one it closed. `processIdentity` catches every failure into `null`, and on two of three platforms that failure is a subprocess timeout on a live process: the win32 `Win32_Process` CIM query and the POSIX `ps -o lstart=` both run on a 2 s budget, under exactly the load that made the HTTP probe miss in the first place. A `null` compared unequal to the saved token, so the record was deleted and `wrapperIdentity` — the only PID-reuse guard `--stop` has — was gone for good. Only Linux, reading /proc directly, was reliable. No answer is now distinguished from a different answer: the PID is checked with `kill(pid, 0)` first, which asks the kernel without signalling and treats EPERM as alive. A PID nothing can signal is gone and retires the record with no subprocess at all; a signalable PID whose token cannot be read keeps it. Only a token that comes back and differs retires it. That ordering also answers the `--list` note: the identity subprocess no longer runs for the stale records that made it slow, so the N x 2 s worst case is gone along with the timeouts that fed the bug. Verified by mutation: restoring the old "no answer means gone" behaviour reds the new case. Also clean up the temp file when a rename fails, rather than orphaning it in the session directory. * test(cli): assert only what the birth-token lookup actually guarantees `captures a stable birth token for the current process` made two assertions that a lookup allowed to fail cannot support. `processIdentity` returns null whenever the lookup cannot be completed — not only when the process is absent — and on Windows and macOS it shells out to PowerShell or `ps` on a 2 s budget that a cold CI runner routinely outruns. Both failed on windows-latest, in sequence: first `.toMatch()` received null, and once that was guarded, `expect(second).toBe(first)` compared a null from the cold first spawn against a token from the warm second one. Two lookups can disagree for exactly one reason — one of them failed — so stability is only assertable across two successful ones. The token itself cannot change between calls; it is a birth timestamp and the process did not restart. `processIdentity(-1)` stays unconditional: the guard rejects it before any subprocess runs. The strict shape assertion moves to a Linux-only case, where /proc is read directly with no subprocess and null is genuinely not allowed — keeping the guarantee on the one platform that can honour it rather than dropping it everywhere. Callers already depend on this contract: `wrapperProcessIsAlive` treats null as "no answer" rather than "gone" precisely because it is reachable.
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 running at http://localhost:3002
npx hyperframes preview --port 4567
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
Related packages
@hyperframes/core— types, parsers, frame adapters@hyperframes/engine— rendering engine@hyperframes/producer— render pipeline@hyperframes/studio— composition editor UI