...A sending screen continuously displays encoded frames while a receiving camera captures enough of them to reconstruct the original payload. The system requires no direct network path, pairing process, native application, or permission beyond camera access. Fountain coding makes the stream tolerant of missed, blurred, duplicated, and out-of-order frames without requesting retransmission. Each QR frame includes session and file metadata, allowing a receiver to join an active stream or reset when a new session begins. ...