Build a lazy compositor for video, a stacked-matte clip. The canvas takes the
colour half's size as soon as the video's metadata is known (so a CSS
height: auto keeps the clip's true aspect) and is returned unattached —
the caller places it where the <video> would have gone. The video must be
readable by WebGL: same-origin, a blob URL, or crossOrigin = 'anonymous'
against a CORS-enabled server (set BEFORE its src).
Build a lazy compositor for
video, a stacked-matte clip. The canvas takes the colour half's size as soon as the video's metadata is known (so a CSSheight: autokeeps the clip's true aspect) and is returned unattached — the caller places it where the<video>would have gone. The video must be readable by WebGL: same-origin, a blob URL, orcrossOrigin = 'anonymous'against a CORS-enabled server (set BEFORE itssrc).