Capture the current video frame from a MediaStream into a Blob at the
stream's full intrinsic resolution. Throws SnapshotError on failure.
Implementation: bind the stream to an offscreen <video>, wait for the
first decoded frame, draw it onto an offscreen <canvas> at
videoWidth × videoHeight, then encode via canvas.toBlob.
Capture the current video frame from a MediaStream into a Blob at the stream's full intrinsic resolution. Throws SnapshotError on failure.
Implementation: bind the stream to an offscreen
<video>, wait for the first decoded frame, draw it onto an offscreen<canvas>atvideoWidth × videoHeight, then encode viacanvas.toBlob.