Browser compatibility and deployment

Status vocabulary

Automated means a checked repository workflow. Supported means the public capability and fallback contract is implemented. Certified requires the documented physical-device and long-session evidence. An API existing in a browser is not the same as an exact configuration passing preflight.

The device matrix records the status of each profile. Emulated profiles run a browser engine/viewport in CI and are not a physical device. Pending-capture profiles are wired and emit evidence on the next nightly capture. Pending credentials profiles (physical devices, driver matrices) require a device-farm credential and must never be reported as certified until their evidence checklist is complete.

Current automated coverage

The repository runs type, unit, schema, API, package, Chromium browser, Firefox browser, and documentation gates. Playwright WebKit/mobile viewports cover public fallback contracts; physical Safari, iOS, Android, device codec matrices, and production HDR certification remain separate evidence work.

The current RC local color contract is RGBA8 SDR. Treat AV1, HEVC, 4K, WebGPU, HDR, OPFS, and hardware codec combinations as negotiated capabilities.

HTTPS

Deploy production applications and media over HTTPS. Service workers, secure storage, worklets, cross-origin isolation, and several media primitives have secure-context requirements.

COOP and COEP

For the preferred shared-memory audio path:

Cross-Origin-Opener-Policy: same-origin
Cross-Origin-Embedder-Policy: require-corp

Every embedded script, worker, font, image, and media response must also satisfy CORS/CORP. When isolation is unavailable, use the documented bounded fallback rather than assuming SharedArrayBuffer.

Media CDN

Serve correct MIME and length, support Range/Content-Range, allow the application origin, and define credential behavior. Test seek near the end of a large file, not only initial playback.

Worker, Worklet, and CSP

Deploy the renderer worker, export worker, and AudioWorklet as explicit runtime assets. Configure worker-src, script-src, connect-src, media-src, img-src, and font rules narrowly. Do not enable arbitrary remote scripts to make a worker load.

4K, mobile, and HDR

Use real-device preflight and budgets. Mobile backgrounding, thermal throttling, memory pressure, screen lock, and browser lifecycle can end long jobs. HDR requires compatible Project metadata, working space, renderer, surface, encoder, container, display, and validation; never silently present SDR as certified HDR.

Device matrix

compatibility/device-matrix.json lists every profile and its status. Automated emulated profiles (reference desktop Chromium/Firefox, WebKit contract, mobile viewport) emit browser evidence bound to the source revision. Physical profiles (macOS/iOS Safari, Android Chrome, GPU driver matrices) are pending-credentials: they require a device farm and their evidence checklist (codec, GPU, audio, storage, export, lifecycle as applicable) must be complete before any certified claim. pnpm report:device-matrix captures the emulated evidence and writes reports/baseline/device-matrix-evidence.json; report:device-matrix:check validates the matrix without recapturing.