Festifools Video: Take Two

For the past several months, YouTube does not successfully embed in LJ, and Vimeo only works if I use an extremely out-of-date embed code. I haven't got my LJ "Post an Entry" page set to the WYSIWYG "Rich text" mode. It's always on HTML. But now I clicked "Disable Auto-Formatting" and after the page loaded for nearly a minute, it worked.