## What a user can do now
Render a video at 720p or 480p: `hyperframes render --resolution 720p` (or `480p`, or the presets `landscape-720p`, `portrait-480p`, `square-720p` and so on) gives a 1280×720 or 854×480 file from a 1080p composition, and the same presets work through the studio-server render route. Before, any preset smaller than the composition was refused ("Downsampling via --resolution is not supported").
## How
- `parsers/src/types.ts`: six presets, `{landscape,portrait,square}-{720p,480p}`, and the `720p` / `480p` aliases (aspect-agnostic, like `1080p` and `4k`). 480p at 16:9 is 854×480: 480 × 16/9 is 853.33, and 4:2:0 encoders need even sides.
- `checkOutputResolutionCompatibility` now allows a preset smaller than the composition. A smaller preset may be off by under one pixel on its long side (the 854); a larger one must still match exactly and be a whole multiple, as before. The aspect remap that `--resolution 1080p` / `4k` apply on their own (`suggestMatchingPreset`, used by the CLI preflight and the compile stage) returns only a preset in the asked tier, never another: with the looser match for smaller presets, a 1922×1080 composition asked for `4k` would otherwise have been remapped to 480p. It is refused instead, as before.
- `resolveDeviceScaleFactor` returns the long side's ratio, so a smaller preset renders at a device scale factor under 1: Chrome lays the page out at composition size and rasterizes each frame straight at 1280×720 or 854×480, the way 4K already renders at 2. For 480p that is 854/1920: the width lands on 854 exactly and the height's 480.375 rounds to 480, so no pad column is added. Output sizes round as Chrome rounds the screenshot.
- The streaming encoder was given the composition's size instead of the output size on both streaming paths (`renderOrchestrator.ts`). 4K never noticed, as both sizes are even; at 480p the encoder skipped its even-size pad and libx264 refused an odd frame (`width not divisible by 2 (853x480)`). It now gets the output size, as the disk-frame encode already did.
- The paths that refused DPR > 1 (BeginFrame, drawElement, the Linux fast-capture gate) now refuse any DPR other than 1, since none of them honor a scale; scaled renders take the screenshot path, as 4K does.
- `render/outputScaleRoute.ts`: the layered compositor (HDR content, and shader transitions in webm and mov) sizes its layers and encoder from the composition and never scales, so a scaled output on that route now stops with a named error, checked where every route and replan is settled (`syncCapturePlan`, beside motion blur's route check). Before, a 1080p request from a 4K composition with shader transitions as mov would have encoded 3840×2160. HDR with `--resolution` was already refused in preflight; 4K on this route had the same gap on main and gets the same error.
## What I measured
- Real renders from source on a Linux box (`bun src/cli.ts render registry/examples/nyt-graph --resolution 720p|480p|1080p`), checked with ffprobe: 720p `h264, 1280x720, yuv420p, 15.0 s`; 480p `h264, 854x480, yuv420p, 15.0 s`; 1080p unchanged at 1920x1080. A frame of each, looked at: same chart and layout, crisp text, and the 480p right-edge column is the page's own color (250,248,242), not a pad.
- Before the encoder-size fix the 480p render failed with `[libx264] width not divisible by 2 (853x480)`; after it, it renders.
- `outputScaleRoute.test.ts`: the real route choice for a 4K composition with shader transitions as mov (`outputSupportsPageSideShaderCompositing`, `shouldUseLayeredComposite`, `createCapturePlan`, `resolveDeviceScaleFactor`) lands on `hdr_layered` at scale 0.5 and is refused. CLI preflight and the compile stage both refuse `4k` on a 1922×1080 composition.
- fails without the fix: without the same-tier rule, the preflight and compile tests for 1922×1080 at `4k` pass the render through at 854×480; without the route check, the mov test does not throw.
- At d33c4458: producer `outputScaleRoute` + `compileStage` 18/18 three runs in a row, `shared` (bun) 9/9, cli `render` 104/104 once and its new test three runs in a row; tsc clean in producer and cli. Earlier at e72f6507: parsers `outputResolutionCompatibility` 20/20, core `index` 26/26, producer `resolveDeviceScaleFactor` 14/14, cli `render` + `parseOutputResolution` 122/122, studio-server `render` 53/53. The new cases fail on main (the presets don't exist; smaller presets are refused). tsc clean in parsers, engine, producer and cli; oxlint and oxfmt clean.
## What I did NOT exercise
- Distributed (Lambda / Cloud Run) renders at 720p/480p: the chunk worker's sizes round the same way, but I did not run a distributed render.
- Studio's render queue keeps its own copy of the rule (`RenderQueue.tsx` `scaleApplies`) and offers no 720p/480p option; unchanged here.
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.
audio
Measure where sounds land: onsets, the moment each sound peaks, loudness and silence. Give files, or query the film's own clips in film time:
npx hyperframes audio sfx/whoosh.mp3
npx hyperframes audio --at 12 --json
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
A render stops when the process that started it exits. To keep one running after
its launcher exits, set HYPERFRAMES_RENDER_DETACHED=1 and start it in its own
process group, e.g. bash -c 'set -m; HYPERFRAMES_RENDER_DETACHED=1 npx hyperframes render -o out.mp4 < /dev/null > render.log 2>&1 &'.
Piped, non-quiet renders emit a single @hf-diagnostic JSON line when an audio
failure reaches the CLI error handler. Version 1 has operation: "render" and
at most 16 audioFailures: allowlisted stage, reason, owner, retryable, and
optional subprocess exit code, signal, termination reason and OS code. It omits
messages, stderr, source paths/URLs, element IDs and command arguments. Consumers
must ignore unknown versions and fields. This is local CLI output; uploading it
requires the caller's existing consent and privacy checks. Quiet mode (including
batch JSON mode) emits no diagnostic line.
This covers audio preparation and mix failures, including the typed external interruption path. Probe failures retain their existing stage/reason but do not gain subprocess evidence here; browser/FX failures remain classified as internal. Desktop ingestion and live report delivery are separate changes.
publish
Upload a project directory and get a hosted URL that keeps working after the CLI exits. Published projects are private by default:
npx hyperframes publish
npx hyperframes publish ./my-video
npx hyperframes publish --public
npx hyperframes publish --yes
Signed-out publishing returns an authentication-required claim URL; opening it
lets someone sign in and claim the project. Sign in first with
npx hyperframes auth login to publish an owned project you can update. Use
--public to make the claimed project visible to anyone. --yes only skips the
confirmation prompt and does not change visibility.
Signed-in publishers can use --update <url-or-id> to target an existing project
or --space <space-id> to publish into a shared team space. If the requested
project is missing or inaccessible, publishing can create a new project instead;
check the printed URL and status.
See the publish reference for all options, including video proxy settings.
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