Did you do a ISP speed test to see if this wasn't ISP related as well?

WestEnd said

Did you do a ISP speed test to see if this wasn't ISP related as well?

Chrome displays the MP4s on the same page within with a few seconds, so I don't see how it can be anything other than something to do with Firefox.

You can check the Web Console (Tools -> Web Developer) for messages about blocked content and about the presence of mixed or unsafe content.

• https://developer.mozilla.org/en/Tools/Web_Console

You can check the timings in the Network Monitor to see if there are excessive loading times.

• https://developer.mozilla.org/en/Tools/Network_Monitor

If necessary use "Ctrl+F5" or "Ctrl+Shift+R" to reload the page and bypass the cache to generate a fresh log.

Boot the computer in Windows Safe mode with network support to see if that has effect in case security software is causing problems.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

Please uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Then run Windows Disk Cleanup. (Note: This should be Pinned and run Weekly, If never done below expect 10's of gig's) Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. But you should make a back up before you do :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Reinstall with Current Release Firefox 57.0.4 with a Full Version Installer

• https://www.mozilla.org/firefox/all/

Please let us know if this solved your issue or if need further assistance.

Why would this speed up downloading of MP4 files?. The page which "contains" the videos loads & opens immediately. It is the MP4 file which takes several minutes to download ready to play within the page. The H264 codec is installed and the files do eventually play. As I said Chrome loads and plays the video files within about a second; the exact time matching the file size with my 50Mg/s download speed.

There's something strange about this page when I look at the "Network Monitor" tool. As shown on the attached screenshot, it seems that the video is requested over and over. The 206 code on the left indicates partial content, which is common for large files, but when I click a song to look at the Headers on the right side, there are odd entries for the range. For example:

20 dec17 - Achey Breaky Heart.mp4 Note: sections of the video may be received out of order. Unless otherwise specified, Firefox requested that the video be sent from the beginning.

9.85 KB received -- far short of the 20MB promised in the Content-Range:

Content-Length 20227461 Content-Range bytes 0-20227460/20227461

19.29MB received -- complete!

Content-Length 20227461 Content-Range bytes 0-20227460/20227461

16.15MB received -- not enough

Content-Length 20227461 Content-Range bytes 0-20227460/20227461

199.68 KB received -- Firefox requested this chunk, very close to complete

Content-Length 206213 Content-Range bytes 20021248-20227460/20227461

9.85 KB received -- no good

Content-Length 20227461 Content-Range bytes 0-20227460/20227461

201.38 KB received -- Firefox requested this chunk, looks good

Content-Length 206213 Content-Range bytes 20021248-20227460/20227461

138.37 KB received -- Firefox requested this chunk, a bit short?

Content-Length 140677 Content-Range bytes 20086784-20227460/20227461

705.85 KB received -- Firefox requested this chunk, not fully received

Content-Length 3319173 Content-Range bytes 16908288-20227460/20227461

85.93 KB received -- not close...

Content-Length 20227461 Content-Range bytes 0-20227460/20227461

I can't see why there are so many requests, and so many failures.

Pkshadow said

Please uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Then run Windows Disk Cleanup. (Note: This should be Pinned and run Weekly, If never done below expect 10's of gig's) Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. But you should make a back up before you do :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Reinstall with Current Release Firefox 57.0.4 with a Full Version Installer

• https://www.mozilla.org/firefox/all/

Please let us know if this solved your issue or if need further assistance.

Why I say to do it is it takes less than 7mins, you do not loose anything and if a program file was corrupted it is replaced as well all the patch over patches of Netscape Browser are no longer there and running pure Quantum files. I do not do this for sake of doing. There are reasons. Follow them or not.

jscher2000 said

There's something strange about this page when I look at the "Network Monitor" tool. As shown on the attached screenshot, it seems that the video is requested over and over. The 206 code on the left indicates partial content, which is common for large files, but when I click a song to look at the Headers on the right side, there are odd entries for the range. For example: 20 dec17 - Achey Breaky Heart.mp4 Note: sections of the video may be received out of order. Unless otherwise specified, Firefox requested that the video be sent from the beginning. .... snip.... Content-Length 20227461 Content-Range bytes 0-20227460/20227461 I can't see why there are so many requests, and so many failures.

Thanks 'jscher2000. This "rang a bell" that I seem to recall that though Xara Website Designer allows "dynamic width variations" for a site there was a warning that more than two might cause problems. My Catstrand site has three, Desktop / Tablet / Mobile. This worked fine in Chrome & Internet EXplorer, but was painfully slow to load the MP4s with Firefox & Edge.

So I have spent some time today, doing various "test versions" of the site:

a) Just a couple of pages, containing videos, and only the full size main varient. - Worked fine on all my test browsers. b) The full site but again only with the one full size varient. - Again worked fine - ~1 sec for a 50MB video . c) Now trying full site with The Main & Mobile sized varients.

No idea why it starting being a problem, unless site size or number of files caused the problem.

Oh well press on. Thank you for your assistance.

Pkshadow said

Pkshadow said

Please uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Then run Windows Disk Cleanup. (Note: This should be Pinned and run Weekly, If never done below expect 10's of gig's) Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. But you should make a back up before you do :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Reinstall with Current Release Firefox 57.0.4 with a Full Version Installer

• https://www.mozilla.org/firefox/all/

Please let us know if this solved your issue or if need further assistance.

Why I say to do it is it takes less than 7mins, you do not loose anything and if a program file was corrupted it is replaced as well all the patch over patches of Netscape Browser are no longer there and running pure Quantum files. I do not do this for sake of doing. There are reasons. Follow them or not.

Reply corrected

Thanks Pkshadow I had already done that with just the same result. If my test mentioned above still does not work then I will try what you say again, making sure I do not miss any step. Thank you for your help. Regards

    Gavin