<video> plays in other browsers, but not Safari

Question

We have an MP4 video on our site; it plays fine in IE9+, Firefox, Chrome, and Chrome on mac. However, on Safari, the video doesn't play at all - it does trigger a "stalled" event and then nothing loads. I would post our HTML, but I traced the problem further by finding that Safari wouldn't play it even when navigating to the original MP4's URL. When downloaded and played locally, the video works fine in Quicktime.

The weirdest part of this is that of all our developers, I can get the video to work on Safari when I run the related server from my development computer. What's more, other MP4 files in the same directory have a similar problem. This has been the key to me, and I've been searching for any little difference in the way the videos transfer from the server - request/response headers, exact filesize, etc.

Headers copied from Chrome (only since Safari is harder to copy/paste from)

Accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Encoding:gzip, deflate, sdch
Accept-Language:en-US,en;q=0.8
Cache-Control:max-age=0
Connection:keep-alive
DNT:1
Host:*************:8443
User-Agent:Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36

Response Headers
Accept-Ranges:bytes
Content-Length:44875102
Content-Type:video/mp4;charset=UTF-8
Date:Tue, 30 Dec 2014 21:11:51 GMT
ETag:W/"44875102-1419959755000"
Last-Modified:Tue, 30 Dec 2014 17:15:55 GMT
Server:Apache-Coyote/1.1

(Also, just in case this reminds you of an older issue; I'm aware Safari on Windows has been dead for ages. This issue is occurring on OS X)

EDIT: New info that might help a bit. I took a personal video from my own webserver, which was able to work from there on the problematic Safari browsers in question, and downloaded it to our server's local video directory. From there, it encounters the same issue as our other videos. This suggests to me that the MP4 itself may not matter - this is probably a server issue of some sort with our Tomcat 7 webserver. We do have the Content-Types registered correctly, which at least covers the basics, but I am curious if there are other necessary parts.

MORE INFO: I didn't think to mention this initially, but we are loading our webpages and videos over an HTTPS connection. Most of our test servers do not have valid certificates, and so we need to click through the standard browser warning that "This server might not be who it says". We are now looking into what it would take to have correct certificates on all our servers.

Answer 1

Safari requires webserver to support "Range" request header in order to play your media content.

https://developer.apple.com/library/safari/documentation/AppleApplications/Reference/SafariWebContent/CreatingVideoforSafarioniPhone/CreatingVideoforSafarioniPhone.html#//apple_ref/doc/uid/TP40006514-SW6

For a legit "Range" request response, your webserve need to return status code "206".