Glass SDK · phase 4

glass.watch() — beside a real YouTube iframe

A real third-party YouTube player (loaded via the public IFrame API — no key, $0) wrapped with Glass.adapters.youtube(player) and handed to glass.watch({ player, videoId, mount, vttUrl }). The GlassWatch companion mounts beside the iframe: interactive transcript, tap-to-explain terms, and a catch-me-up recap.

companion: loading YouTube API…

⚑ In-caption isn't available on iframe players — by design. A YouTube player is a cross-origin iframe, so the page cannot reach its inner <video> or its captions. The companion therefore runs companion-only: the host's own captions stay on the video, and the interactive transcript comes from a supplied vttUrl. Where Glass can reach the player's <video> (native, JW, Brightcove), in-caption tapping is possible instead.

Programmatic control

Event log

Waiting for events… (turn on the companion, tap a term, or toggle catch-me-up)

Demo notes — this page loads /glass.umd.js and the public https://www.youtube.com/iframe_api (no API key). It calls the public Glass.adapters.youtube() + Glass.watch() API; nothing here is inline companion code. AI is gated on turn-on and runs on the mock model ($0) until owner go-live.