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Firefox display odd characters when I click an mp4 link

  • 4 replies
  • 1 has this problem
  • Last reply by dclower

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Up until about a month ago, I could click a link to an mp4 file and it would stream in my browser perfectly - now, I get square characters and question marks - just a bunch of giberish. These videos play perfectly in Safari, Chrome and IE. I'm on FF 31.0 and the browser reports that Firefox is up to date. What changed with the recent updates?

All Replies (4)

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This happens if the server sends the file as text/html or as text/plain. In such a case Firefox will try to render the page instead of opening it in a media player.

This can also happen if you ever got the "Open with" dialog when you clicked such a link and have chosen to open file in Firefox. You should never do this to avoid such an issue and you will have to remove this action in Firefox > Preferences > Applications

If that wasn't possible then rename (or delete) the mimeTypes.rdf file in the Firefox profile folder to reset all file actions.

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I'm not aware of any changes that would have instructed the server to stream an mp4 video file as text/html or as text/plain.

As for "Open with", I never made that selection (nor was I ever given that option). Currently in Firefox > Preferences > Applications the setting for MPEG-4 Video is set to "Use QuickTime Plug-in 7.7.3 (in Firefox)".

I'm sure I should dig a little deeper but I'm having difficulty finding the mimeTypes.rdf file on my system - tell me where I should look for it. (Mac OSx).

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What does it say in Tools > Page Info > General if you have such a page in a tab about the content type?

You can also check this in the Web Console (Firefox/Tools > Web Developer) or with the Live Http Headers extension

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It does report it as text/plain, but three other browsers that I use for testing on this content do not have difficulty rendering the videos.

Type: text/plain Render Mode: Quirks mode Encoding: windows-1232