therube wrote:Oh, you're on XP, & that might be the issue?
On XP now, & I get no video, only "This browser does not support video playback".
Thanks for confirming this on Win-XP. That's the error message I get. On certain other MP4 content pages on other web sites, I get the more usual message ""No video with supported format and MIME type found". I believe it's just that Twitter uses its own error message to convey the same issue. I think this is the first instance where the operating system has caused issues for me in web browser because I had always assumed that having the necessary plug-ins would handle all necessary content formats and make the browser OS-independent.