How can I play H264 videos and MP3 audio in Firefox on Windows 7 N Professional without installing Windows Media Feature Pack? I know you can use GStreamer on Linux, but it doesn't work on Windows. I've installed gstreamer-1.0-x86_64-1.4.1.msi from here with Complete setting, restarted Firefox and I still cannot play H264 videos.

  • Why can't you install the Windows Media Feature Pack?
    – slhck
    Sep 18, 2014 at 9:15
  • 1
    I chose N version to have system without it. I don't want to install it. There has to be some other way to make it work.
    – user369708
    Sep 18, 2014 at 9:36

3 Answers 3


I know this is an old question, and directed at Windows 7 N, but this answer most likely will work on Windows 7 as well. Since I couldn't find the answer anywhere, I played around with Process Monitor (Sysinternals) to find the required files and registry keys. Tested successfully on Pale Moon 28.2.1 (x64) with H264 playback on Twitter and YouTube.

On Windows 10 N 64-bits, all you seem to need is the following (at least for H264 playback):

The file mfperfhelper.dll in your application folder (or Windows\System32 folder)
The file msmpeg2vdec.dll in your Windows\System32 folder
The file mf.dll in your Windows\System32 folder
The file mfplat.dll in your Windows\System32 folder
The file evr.dll in your Windows\System32 folder

Extract these files from the Media Feature Pack installation file appropriate for your Windows version architecture (64-bits - amd64).

The following registry entries: (copy/paste to .reg file and import by double-clicking the file)

Windows Registry Editor Version 5.00

@="Microsoft H264 Video Decoder MFT"


@="MF Media Source Activate"


On Windows 10 N 64-bits (build 1809) it works, but blocks 'windows settings app'. Even adding the missing file mfcore.dll. Removing the registry key HKCR\CLSID{e79167d7-1b85-4d78-b603-798e0e1a4c67} "MF Media Source Activate" 'windows settings app' returns to work.

  • I can confirm this. After removing key HKCR\CLSID{e79167d7-1b85-4d78-b603-798e0e1a4c67} Settings app will work again but firefox playback stops working :(
    – Milos
    Mar 7, 2020 at 15:26

For Windows 7 SP1 N x64 it was enough to copy fallowing files:

  • mf.dll in your Windows\System32 folder
  • mfplat.dll in your Windows\System32 folder
  • evr.dll in your Windows\System32 folder

Here are extracted files

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