Bizarre bug: in a PHP script that serves video files, I have a few test conditions (authenticate token, make sure file exists, etc.) before sending a \"video/mp4\" header an
The only reason for it to render a blank page would be that it does in fact enter the exit; statement. You mentioned an authentication token, could that be missing when testing in safari? Firebug and Safari's developer tools can also help you with debugging (check the response headers, etc).