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Vance Ingalls
f906797222
## Summary Coalesce writes to `el.currentTime` inside `_mirrorParentMediaTime` so a single jitter sample no longer triggers a parent-media seek. A drift correction now requires **two consecutive samples** above the threshold (~`MIRROR_DRIFT_THRESHOLD_SECONDS`) before the player writes back. One-shot alignment paths (`promoteToParentProxy`, `_onIframeMediaAdded`) opt out via `force: true` so initial alignment stays immediate. ## Why Step `P1-4` of the player perf proposal. `_mirrorParentMediaTime` is called every animation frame on parent media proxies. Even without true drift, browser internals report tiny jitter on `currentTime` reads — typically below 30 ms but occasionally crossing the threshold for a frame. Writing to `currentTime` triggers a seek, which is expensive *and* invalidates pipeline buffers, which causes the next frame's reading to jitter further. The result was unnecessary seek thrash on otherwise-aligned media. By requiring two consecutive over-threshold samples, transient jitter is filtered out while real drift (a sustained offset) still corrects within ~1 frame of latency. This eliminates the most common cause of dropped frames on the studio thumbnail grid. ## What changed - Each `_parentMedia` entry gains a `driftSamples` counter that increments while the absolute drift is above `MIRROR_DRIFT_THRESHOLD_SECONDS` and resets to 0 on the first sample below. - `_mirrorParentMediaTime(el, opts)` only writes back when `driftSamples >= 2`, except when `opts.force === true`. - `promoteToParentProxy` and `_onIframeMediaAdded` pass `force: true` so the first alignment after registration is still immediate (these are user-visible state transitions, not steady-state telemetry). ## Test plan - [x] 11 new unit/integration tests in `hyperframes-player.test.ts` covering: - Single-sample jitter does not trigger a write. - Two-sample sustained drift does trigger a write. - Trending drift correction (gradually increasing offset) is detected within 2 samples. - `force: true` override bypasses the sample requirement. - Out-of-range proxies (proxies whose source has been removed) do not panic. - Multiple proxies maintain independent counters — drift on one does not affect the other. - `_promoteToParentProxy` alignment is immediate. ## Stack Step `P1-4` of the player perf proposal. Builds on `P1-1` (shared adopted stylesheets) and `P1-2` (scoped media observer). Together these three target the studio multi-player render path — `P0-1*` perf gate scenarios will pick up the wins automatically.
@hyperframes/core
Types, parsers, generators, compiler, linter, runtime, and frame adapters for the Hyperframes video framework.
Install
npm install @hyperframes/core
Most users don't need to install core directly — the CLI, producer, and studio packages depend on it internally.
What's inside
| Module | Description |
|---|---|
| Types | TimelineElement, CompositionSpec, Asset, canvas dimensions, defaults |
| Parsers | parseHtml — extract timeline elements from HTML; parseGsapScript — parse GSAP animations |
| Generators | generateHyperframesHtml — produce valid Hyperframes HTML from a composition spec |
| Compiler | compileTimingAttrs — resolve data-start / data-duration into absolute times |
| Linter | lintHyperframeHtml — validate Hyperframes HTML (missing attributes, overlapping tracks, etc.) |
| Runtime | IIFE script injected into the browser — manages seek, media playback, and the window.__hf protocol |
| Frame Adapters | Pluggable animation drivers (GSAP, Lottie, CSS, or custom) |
Frame Adapters
A frame adapter tells the engine how to seek your animation to a specific frame:
import { createGSAPFrameAdapter } from "@hyperframes/core";
const adapter = createGSAPFrameAdapter({
getTimeline: () => gsap.timeline(),
compositionId: "my-video",
});
Implement FrameAdapter for custom animation runtimes:
import type { FrameAdapter } from "@hyperframes/core";
const myAdapter: FrameAdapter = {
id: "my-adapter",
getDurationFrames: () => 300,
seekFrame: (frame) => {
/* seek your animation */
},
};
Parsing and generating HTML
import { parseHtml, generateHyperframesHtml } from "@hyperframes/core";
const { elements, metadata } = parseHtml(htmlString);
const html = generateHyperframesHtml(spec);
Linting
import { lintHyperframeHtml } from "@hyperframes/core/lint";
const result = lintHyperframeHtml(htmlString);
// result.findings: { severity, message, elementId }[]
Documentation
Full documentation: hyperframes.heygen.com/packages/core
Related packages
@hyperframes/engine— rendering engine that drives the browser@hyperframes/producer— full render pipeline (capture + encode)hyperframes— CLI