HTML 5 Video tag don't play mp4 videos

  • Hello from Germany, i use the 32bit Version on Windows 8.1 64bit System and the video with mp4 on follow side can't be run. What is the problem or can't Vivaldi play html 5 video tags with mp4? All other Browser can play the file. Greetings

  • Moderator

    Vivaldi as modern browser can play MPEG-4 in HTML5 element video. In your case it is not the browsers fault.

    The webserver of the page Microsoft-IIS/7.5 is broken. I hope it is not your own misconfigured server.

    Please Inspect this in Vivaldi:
    Open webpage in Vivaldi
    Open Developer tools with Ctrl Shift I
    Select the tab Network
    Reload Page with Ctrl F5
    Select in left pane the Name SnippetServer.mp4
    Select in right pane Headers

    See Response header:

    HTTP/1.1 206 Partial Content
    Content-Type: video/x-mp4
    Last-Modified: Wed, 27 May 2015 12:32:48 GMT
    Accept-Ranges: bytes
    ETag: "e4e8be3d7998d01:0"
    Server: Microsoft-IIS/7.5
    X-Powered-By: ASP.NET
    Date: Fri, 08 Apr 2016 07:01:29 GMT
    Content-Length: 5594495
    Content-Range: bytes 0-5594494/5594495

    Grausig. haareraufend SCNR

    It sends the wrong MIME type!
    video/x-mp4 is not a correct mimetype for a MPEG-4 Video!
    See for correct types at

    Please inform the admin of the server for setting the correct MIME type to video/mp4 and all is fine.

  • That was it! Thx a lot.

    No isn't my own Server, it is from my Provider 1&1. But i have admin rights to this Server. I have change the entry in the web.config and now it runs.

    But i wonder how it could runs under chrome firefox and ie… So what it goes.

    I like Vivaldi for his performans, faster than the other!

    Good job you make there!! Thanks and Greetings

  • Moderator

    It is better to use the correct MIME types than forcing browsers to guess or sniff, because that may result to security problems.

    That is the job of a person who owns a server: to do the right work. 😉

    PS: Freut mich, dass es klappt.
    Grüße aus Franken.


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