We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

Avatar for Username

搜索 | 用户支持

防范以用户支持为名的诈骗。我们绝对不会要求您拨打电话或发送短信，及提供任何个人信息。请使用“举报滥用”选项报告涉及违规的行为。

详细了解

话题已存档。 如果需要帮助请提出新问题。

MP4s unable to play (Windows Home Edition)

  • 3 个回答
  • 1 人有此问题
  • 1 次查看
  • 最后回复者为 cosey

cosey
cosey
more options

The whole system was only set up recently, so I'm not sure if the issue has been happening since Firefox was installed, but it is possible.

I've narrowed it down to MP4s being the issue, which as the relevant help articles state should be decoded by the OS. No problems watching the videos in Microsoft Edge for example.

Console gives: 

   HTTP "Content-Type" of "video/mp4" is not supported [...]
   Cannot play media. No decoders for requested formats: video/mp4

or 

   Specified "type" attribute of "video/mp4" is not supported

etc.

Same result when disabling all addons. Windows Media Player etc. installed and working.

Only the first (MPEG) video on the following test page doesn't work for example: https://tekeye.uk/html/html5-video-test-page

Any help would be greatly appreciated!

The whole system was only set up recently, so I'm not sure if the issue has been happening since Firefox was installed, but it is possible. I've narrowed it down to MP4s being the issue, which as the relevant help articles state should be decoded by the OS. No problems watching the videos in Microsoft Edge for example. Console gives: HTTP "Content-Type" of "video/mp4" is not supported [...] Cannot play media. No decoders for requested formats: video/mp4 or Specified "type" attribute of "video/mp4" is not supported etc. Same result when disabling all addons. Windows Media Player etc. installed and working. Only the first (MPEG) video on the following test page doesn't work for example: https://tekeye.uk/html/html5-video-test-page Any help would be greatly appreciated!

被采纳的解决方案

Ok I have no idea how this happened, but looking in about:config I discovered that 

   media.mp4.enabled

was somehow set to false!

Reverting that to its default true has fixed the issue.

定位到答案原位置 👍 0

所有回复 (3)

ARMAN KHAN
ARMAN KHAN
more options

hello

cosey

follow the steps and instructions:

you may be needing this in case you do not have support for MP4 files:

Windows Media Feature Pack for Windows 7 N and for Windows 7 KN:

Also make sure that these prefs have the default value: 

   media.windows-media-foundation.enabled
   media.directshow.enabled

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue. 

   http://kb.mozillazine.org/about:config

tell me its help

thank you and regards,

Arman

cosey
cosey 提问者
more options

Thanks for the reply Arman.

I'm using Windows 10 Home Edition not Windows 7 N; I already have Windows Media Player installed. I can play MP4s in other areas of the OS (e.g. in Media Player itself, in the Edge browser etc).

Neither of those listed preferences were present. I'm assuming they're booleans and tried adding them but no combination of true/false for them seems to have made a difference.

cosey
cosey 提问者
more options

选择的解决方案

Ok I have no idea how this happened, but looking in about:config I discovered that 

   media.mp4.enabled

was somehow set to false!

Reverting that to its default true has fixed the issue.