Feb 242017

1.) Introduction & Explanation

This is one thing that has brought to me by two users ([SK1] on [Voodooalert]German flag and [liquidLD] who talked to me about this on IRC), and because I got a bit pissed off by it myself, I decided to look into the matter. Basically, HTML5 video on Windows XP / XP x64. But not just with webm (VP8/VP9), but also with H.264/AVC. Let’s face it, a lot of videos on the web rely on H.264 and sometimes you simply can’t watch certain videos or you won’t get all the available resolutions. Of course you could just rely on Adobe Flash, but since Google basically took over with their Pepperflash plugin and their Chrome browser no longer supports XP, it’s not the best move either. Especially when you think about Adobes’ history with critical security loopholes in Flash. HTML5 is just much, much safer, and free as well, and Firefox still supports XP.

Note that this guide is thus based on Firefox exclusively. Anything starting with version 47 should work, official support came in 49, and I’ll be using the current version, 51.0.1 at the time of writing.

So, why doesn’t it “just work” in the first place? It did a few years back, right? Because H.264 playback relies on a DRM plugin, on Linux it would be the Google Widevine plugin, on Windows it’s the Adobe Primetime plugin. So yes, Firefox does support DRM out of the box. But even if content isn’t signed and encrypted, the browser still relies on those plugins to play H.264. And the problem is, that Adobe found some problems with that plugin on XP, so they disabled support on the platform. Their version 17 plugin is still being rolled out with the browser however, and it is binary-compatible with XP, so let’s show you how to re-enable it!

2.) Making it work

On Windows XP and XP x64, the plugin should reside in the folder:

%USERPROFILE%\Application Data\Mozilla\Firefox\Profiles\<your profile folder>\gmp-eme-adobe\17\

That folder should contain the files eme-adobe.dll, eme-adobe.info and eme-adobe.voucher. If it doesn’t (maybe because you have a DRM-free version of Firefox), just create the folder structure yourself, get the necessary files from [here] and place them in that folder.

Having the files present won’t enable Adobe Primetime for you however as you can see on about:plugins (Note: The Cisco stuff you can see there is just for WebRTC, so it’s unusable for HTML5 <video>), we still need to tweak a few things on the about:config page of Firefox. Look for the following properties and set them to the values shown below. If a property doesn’t exist yet – media.gmp-eme-adobe.forceSupported most likely won’t – just create them yourself, all of them are boolean properties and all of them need to be set to true:

media.gmp-eme-adobe.enabled		true
media.gmp-eme-adobe.forceSupported	true
media.gmp-eme-adobe.visible		true
media.gmp.decoder.enabled		true
media.eme.enabled			true
media.mediasource.mp4.enabled		true
media.mp4.enabled			true

After making those changes, you’ll need to restart Firefox. Now you might already be good to go, but on some configurations, about:plugins might show something like this:

HTML5+H.264 on Firefox not yet working

Adobe Primetime seems enabled, but there is no file information? So it’s not actually loading the eme-adobe.dll yet (click to enlarge)

If that happens, open your preferences menu on the top right, click on “Add-ons”, then “Plugins” or just go to about:addons. What you should be seeing is this:


However, if Adobe Primetime shows a notice saying that it’s going to be “installed shortly”, forget it. Just do it manually on the plugins’ options page you can see on the right image. To do so, click “Check for Updates”. The warning should be gone momentarily. After that, re-check about:plugins, and you should be getting this:

Adobe Primetime fully enabled

Adobe Primetime fully enabled (click to enlarge)

3.) Testing

Now you can do a quick check on the [Youtube HTML5 page], and it should confirm that everything’s working:

Youtube confirming full HTML5 video support

Youtube confirming full HTML5 video support including H.264 and Media Source Extensions (click to enlarge)

With MSE, even Javascript players (like the Flowworks player) bytestreaming H.264 to Firefox should work! Of course, that’s not very thorough. What you’d want is a real playback test, since you can never be sure what you’re getting on Youtube without a bit of extra work. Decent playback tests are currently available on [Quirksmode], and it should look like this:

Firefox playing HTML5 H.264/AVC video in Firefox on Windows XP x64

Firefox playing HTML5 H.264/AVC video on Windows XP x64 (click to enlarge)

With this, even stuff like Netflix works, because you’re getting not just H.264 playback, but also DRM support. Now, whether DRM support is a good thing or not… You’ll have to decide that for yourself. I’m not supportive of DRM content on the web, but if you want to view or listen to such content, you can!

Just one last word of warning though: Adobe has ended their support for XP with a reason, as the Primetime content decryption plugin has shown problems and instabilities on XP! I’ve been using this for about a week now, and I’ve had one case of a video getting stuck, which is a typical symptom of Primetime throwing up on you. Don’t worry though, Firefox won’t crash. Just move the video slider a bit or restart the video, and it’ll work again! You don’t even need to restart the browser, and such occurrences seem to be quite rare, so I’m fine with it.

There you go!

4.) Thanks

Big thanks fly out to [the guys at MSFN] who came up with all of this. I basically got 100% of my information from them, so thank you! You rock! :)

Update: If you update your version of Firefox to the latest and final 52.0 ESR (extended support release), the last version which will be officially supported until 09-2017 for XP, you might notice that Adobe Primetime just disappeared after the update. That’s because the installer may delete the property media.gmp-eme-adobe.visible from your prefs.js. To reenable it, you’ll have to manually recreate the boolean property and set it to true:

media.gmp-eme-adobe.visible		true

Restart Firefox after the change, and the plugin should reappear on about:plugins and about:addons!

Update 2: It seems there is an issue with fresh installations of Adobe Primetime when using Firefox 52.x ESR instead of Firefox 51.x ESR, as reported by [Newb the Newbd]. The solution is to open the URL about:config in Firefox once more and look for media.gmp-manager.url. Its value should look something like this: https://aus5.mozilla.org/update/3/GMP/%VERSION%/%BUILD_ID%/%BUILD_TARGET%/%LOCALE%/%CHANNEL%/%OS_VERSION%/%DISTRIBUTION%/%DISTRIBUTION_VERSION%/update.xml. Edit that configuration option and replace the variable %VERSION% with the string 51.0 to fake an older Firefox version. Now check for updates for Adobe Primetime in the plugins section of about:addons. It should install and start working properly now!

CC BY-NC-SA 4.0 How to make HTML5 H.264/AVC video work on Windows XP/XP x64 (using Firefox) by The GAT at XIN.at is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

  108 Responses to “How to make HTML5 H.264/AVC video work on Windows XP/XP x64 (using Firefox)”

  1. Edit by thrawn: The following comments have been merged together into a single one to reduce clutter. While at it, they’ve also been slightly reformatted:

    Comment 1:

    any ideas for 52.7.3 esr (32 bits) portable?
    where should i extract the files?
    i extracted them to: H:\FirefoxPortableESR\Data\profile\gmp-eme-adobe\17

    about:config don’t show anything about adobe

    thanks in advance for any posible help

    Comment 2:

    and how to set those dll to work with firefox??

    Comment 3:

    added the recomended settings manually:

    media.gmp-eme-adobe.enabled		true
    media.gmp-eme-adobe.forceSupported	true
    media.gmp-eme-adobe.visible		true

    then did the trick recomended in UPDATE 2
    finally got installed, tested in youtube and says all compatible format supported
    reverse 51.0 changes and wrote back %VERSION%

    Comment 4:

    got it working. leaved feedback/reply how to get it working for firefox esr 52.7.3 (32 bits) some lines down

    • Hey Ricardo,

      I took the freedom of editing and merging your recent comments, as they do belong together. I hope you’re ok with that!

      Nice to see you got it working! :)

  2. I got mine to work by installing avcodec-lav-57.dll, avresample-lav-3.dll, avutil-lav-55.dll. Download is on the…


    I installed them in Firefox ESR 52.7.3…

    • Hah, so this works just fine on Firefox on XP as well? I’ve used the ffmpeg libraries to fully enable HTML5 on my FF 52 ESR on CentOS 6.9 Linux, but it’s nice to know that the same “New Moon trick” works for FF ESR on XP as well! Haven’t tried it myself yet.

      Well, this won’t give you any DRM capabilities, but neither willl Adobe Primetime these days. ;) So using ffmpeg libraries is maybe even the cleaner solution by now.

    • Simply adding the DLL’s like that doesn’t work for Firefox Firefox ESR 52.7.3.
      Not in XP 32-bit anyway.
      It does work with New Moon (and maybe Palemoon) however.

  3. Happy Easter!

    I followed the tutorial and Quick Check on the youtube html5 page as well as the tests on Quirksmode show that it runs as expected. BUT:
    I can’t get it to work on the DAZN sports stream page. I have no clue, what is going on, the stream repeats to reload each 1-2 seconds, so I actually get to see the picture for a seconds, until it starfsdts trying to reload again. And only with Silverlight installed, even though I hoped to watch it with HTML5 instead. The funny thing isdsaasd, that I tried watching at another pc (with Windows 7) and it works without Silverlight, so what is going on?
    I even used the same Firefox Portable V51.0.1 version, so why do I get asked for Silverlight on my Windows XP machine, but not on the Windows 7 machine?
    And why does it stream fluently on Windows 7 without Silverlight, but keeps reloading again and again on my Windows XP machine with Silverlight?
    I would like to understand technically what’s the matter.
    On the youtube test link you provided, there’s a brief note at the bottom about the availability of H.264-replay being dependant of the used hardware and the OS. Might that be kind of a hint?

    Thanks in advance.

    • Hello Dirk,

      I believe that the remark about “hardware and operating system” on the Youtube [HTML5 page] is meant for mobile platforms more than for the PC, especially given the licensing issues with H.264 on such devices.

      Anyway, I have to apologize, but I can’t really provide any solutions for the DAZN issue. I don’t have Silverlight installed (anymore), even though there are still current versions for XP. So I don’t know what kinds of issues Silverlight may have on XP.

      The only piece of technical information I can provide (and that’s just an educated guess) is, that Adobe Primetime is essentially deprecated, and thus the viewing of certain DRM-protected media via HTML5 fails. Support for the DRM implementation that Adobe Primetime can provide in conjuction with the OS (XP isn’t considered a “trusted platform” by the “content mafia”) has been dropped by a variety of content providers, possibly including DAZN. As a matter of fact, I couldn’t find any DRM-protected stream that still works with Primetime on XP for a while now.

      Like I said, this is just an assumption on my end, but a relatively sane one when looking at other services like Amazon Prime or Netflix. If DAZN is serving DRM-protected content, then this would be a pretty clear case in my book.

      Of course, that doesn’t help you at all. If you cannot use HTML5+H.264+DRM and Silverlight+DRM is also out of the question, then there would only be Adobe Flash, if supported. If it isn’t, I can only shrug my shoulders, as I’m not going to register a DAZN account for myself to test this.

      Bottom line: I believe this to be a DRM issue rather than anything else, when it comes to HTML5. No idea about Silverlight though.

      • Hi thrawn,

        thanks for you great and detailed answer. To be honest, you have made a great guess (out of the blue)!
        DAZN is DRM protected, and in the meantime I have made some further investigations with the following result:
        DAZN is looking for Widevine it seems. After having deactivated that plugin on the Windows 7 PC I found out, that it began to ask for Silverlight just like on my Windows XP computer. I suddenly felt a lightbulb over my head. Conclusion: Adobe Primetime hadn’t been accepted properly, I needed to get Widevine working.
        I had read that it is kind of a Chrome equivalent for Adobe Primetime on Firefox, so I started to install Widevine manually on Chrome 49 and TADA!, unbelievably it was working!
        Hoping to get the same results on Firefox, it failed unfortunately. I found an archive of widevine and installed it manually in the appropriate folder, but Firefox doesn’t list it in about:plugins, it is not recognized. I remember having read on MSFN that someone else was having problems to get widevine working on Windows XP.
        Do you have any suggestions? Otherwise I have to watch DAZN on Chrome.

        • Hey Dirk,

          I see. Well, that was to be expected with DAZN being a commercial service. Unfortunately, I haven’t gotten Widevine to work on XP / XP x64 with Firefox myself either. I never figured out what the problem really was. I even inspected the widevinecdm.dll with [Dependency Walker] and [CFF Explorer], but it checked out without any problems. That .dll should have no issues whatsoever loading on XP, but still, I never got FF 52 ESR to accept it, even with a correct Widevine configuration copied & adapted from a Windows 7 machine.

          So I’m afraid I can’t help with that. Sure would be awesome if we could get FF 52 ESR to accept the Widevine content decryption module on XP, but I have yet to find a way to make it happen…

          • Hi thrawn,

            that’s really disappointing that it is this tough to get it working. Is there a way to check what firefox is actually doing while it is opened? Kind of comparing the plugins loaded with the listed ones? What about the option to load plugins by file? I didn’t succeed in doing so.I did some research and found some hint about deactivating, then activating the option “Play DRM content” in about:preferences#content again. This will cause kind of a refresh and would trigger a Widevine update, but unfortunately I have no chance to give it a try, because I don’t have that option. Do you know why this option might be missing?

            Thanks anyway for your efforts.

  4. Great solution!
    Only 1 disadvantage with XP + Firefox 52(.7.3) + (reactivation of)Primetime:

    Videos which rely on Primetime continue to play at every single update of the sub-version of Firefox, but every update creates the following shutdown problem: After having clicked on “Shutdown” it takes 2 minutes until the window showing the possible shutdown modes.

    I am not sure if this is causally due to Primetime, but the solution on my ASUS notebook is to uninstall the (internal) compound USB device (camera etc.) in the device manager which will be reinstalled automatically during the next start of the system. After this everything works perfectly well again.

    Since I couldn’t find a way to contact the developers of Firefox directly, I beg you all:
    a) Try to get them to adapt the updates in a way leaving the USB driver for the compound device untouched
    b) try to get them not to “destroy” Firefox 52 in May 2018 as announced (at least I understood this), since XP is so NECESSARY probably to many of us, since ALL GADGETS installed (USB-Cams, measuring devices, remote control of the heating and airing of the countryside-house, the principal printer/scanner, the card reader, the video and the cassette digitalizer, etc. etc.) as well as MS Office 2000 (which contains the most direct-to-use MS photo editor), especially EXCEL 2000 (which is much simpler to use, creates much better scientific diagrams and much easier formulas than within office>=2007; also, Office 2000 works with the B_Kainka-API for RS232-input from a lot of devices but “modern” Office can’t!) and Outlook Express (which contains all emails in an order which is lost during a change to thunderbird – or anything else, I think).
    All of this relies on XP and NO DRIVERS are available for all this under Windows 10, to my knowledge. Especially I believe that it would be impossible to make all this work again after virtualization of XP under Windows 7, which might be in vain after support of Windows 7 will have been stopped….

    Therefore I might die (or feel like this) as a person if Mozilla wouldn’t let us continue to use XP….

    Thank you, thrawn, for this thread and this forum!
    Please, continue to help to leave XP and Firefox for XP alive!
    Only in this case, I assume, the wonderful support by Norton Security for XP will continue too.

    • Hello Rudolf,

      Your system shutdown problem sounds very weird indeed. I’ve never encountered anything like this. Also, uninstalling the compound USB device to make it work is kind of obscure. You may wish to try and reproduce the issue on another machine before contacting the Mozilla guys, if at all possible for you.

      Also, about that, you can file bugs at the official [Bugzilla]. They may mark this as a “Won’t fix” though, if you’re running FireFox in a modified way that is not officially supported. :( Well, one can still try.

      at a): I’m not sure what the FF updates would have to do with the USB devices anyway. It’s possible Firefox tries to access the devices (for stuff like videoconferencing support maybe?) in a way that breaks things. If that’s the case, you should really file a bug report. But you should probably make it a vanilla Firefox first, without the unofficial Adobe PrimeTime mod. That way, it’s more likely the Mozilla guys’ll take this serious. If it’s indeed PrimeTime causing the issue, I doubt they’d help, because as said above, they don’t officially support PrimeTime on XP anymore.

      at b): Forget it. It’s not gonna happen. Firefox is a massive software project, and as sad as it may be, they’re not going to alter their development pipelines or EOLs for just a few “obscure” Windows XP users like us. Especially since it’s hard to argue with the security-related argumentation from their side. They’d likely not acknowledge the POSReady2009 hack as a justification for the use of 32-bit XP either.

      After Firefox, you may consider switching to roytam1s’ build of Pale Moon called New Moon, which has been forked from an old Mozilla codebase. From FF 27 I believe. It’s receiving security and smaller feature updates and will continue to receive them in the form of backports even after the “death” of FF on XP. It can play HTML5 videos using bundled ffmpeg LAV libraries, as long as there’s no DRM. But YouTube etc. works. You can find roytam1s’ builds of New Moon here: [Link]. After the current Pale Moon, there will be a new one based on the current FF ESR 52.x version, and that will then continue to live on. There are early versions of that as well, and roytam1 is providing XP-compatible builds of that too!

      I’m currently using it side-by-side with Firefox and Firefox ESR on XP x64, CentOS 6.9 Linux as well as FreeBSD 11.1 UNIX. Soon, I will have made my transition to Pale Moon / New Moon complete. It’s faster too, so yeah. That’s probably the way to go if you want to have a secure browser on XP or XP x64 in the future.

      As for the rest: I had no issues migrating from Outlook Express to Thunderbird. I’m storing my eMails on my own IMAP server, and nothing was messed up, including the ordering by date. Office 2000 is quite an issue though, I’ve installed it on Windows 10 before, but it’s tricky to get it to work properly. And I’m not sure whether the RS232 serial input would work either. I don’t use Office much, and for what little I need, I’ve migrated to LibreOffice. Of course, there is still a lot of stuff that won’t work on modern Windows operating systems, but yeah… I guess the best practice that most people would suggest would be to use a separate XP machine for that which does not have internet access, and a “modern” machine for web browsing etc., so you’d be secure. Naturally, a lot of people just don’t want to do that…

  5. Can confirm the real magic is the gmp-eme-adobe-v17.7z file contents. Even with added about:config statements it doesn’t work without those files in play. AND it fails the you tube html5 test page too. I just renamed them to be the same as I had in 1.6 folder and then overwrote those. Not only does youtube now function without WEBM file available for download from the page, but live stream from Oroville spillway works along with twitter videos and a raft of others I’m sure. None of those work with original 1.6 files in play which I restore at will depending on what behavior I need. Thanks a million. #1 hit with h.264 firefox xp search terms.

    Oroville spillway

    • Lee,

      #1 is a bit scary actually, my ancient homeserver (which has been running relentlessly for ~23 years) can barely handle the load as it is, but oh well…

      I do wonder if this “hack” can actually help people play back DRM-protected content these days? You know, like Amazon Prime video, Netflix and the likes. Probably not… I’m beginning to think that ffvpx (bringing ffmpeg to Firefox), like used in the Palemoon project might be the better option here, if DRM breaks anyway?

    • Thanks, it work!
      Mada a folder and extracted files. After restarting Firefox no mo messages about html5.

  6. THANK YOU! It works perfectly! The only problem that I had was my Primetime Content (update 2) didn’t have an update button, but I found out that if you right click on the web address, a menu would appear with the option to update. Other than that, perfect!

  7. That actually worked, thanks a lot! Had to follow every single step before success, otherwise I was getting zero progress. This is a good example of how the big companies (in this case M$, Mozilla, and Adobe) openly disrespect their users, then the users circumvent all of them. Long live Windows XP, the best OS in history! And longer live the users community!

    • Hello disciple,

      Well, I’d probably say that either Linux or FreeBSD UNIX would be the best OS in history, but you know… always depends on who you ask. ;) Certain strange people might say OpenVMS or even BeOS, heh. In the Windows world, I’d probably nominate XP x64 and Windows 2000… but I digress.

      In any case, I’m happy to have been of help! :)

  8. thank you so much,searching too long to fix and you came to the rescue
    runing on ff E.S.R 52.5.3
    win xp sp3


    media.mp4.enabled  true
    media.mediasource.mp4.enabled  true
    media.eme.enabled  true
    media.gmp-eme-adobe.enabled  true
    media.gmp-eme-adobe.forceSupported  true
    media.gmp-eme-adobe.version  17
    media.gmp-eme-adobe.visible  true
    media.gmp-manager.url  https://aus5.mozilla.org/update/3/GMP/%VERSION%/%BUILD_ID%/%BUILD_TARGET%/%LOCALE%/%CHANNEL%/%OS_VERSION%/%DISTRIBUTION%/%DISTRIBUTION_VERSION%/update.xml
    media.gmp.decoder.enabled  true
  9. That Work i use XP SP2 32bit, FF
    and use this.

    media.mp4.enabled  true
    media.mediasource.mp4.enabled  true
    media.eme.enabled  true
    media.gmp-eme-adobe.enabled  true
    media.gmp-eme-adobe.forceSupported  true
    media.gmp-eme-adobe.version  17
    media.gmp-eme-adobe.visible  true
    media.gmp-manager.url  https://aus5.mozilla.org/update/3/GMP/%VERSION%/%BUILD_ID%/%BUILD_TARGET%/%LOCALE%/%CHANNEL%/%OS_VERSION%/%DISTRIBUTION%/%DISTRIBUTION_VERSION%/update.xml
    media.gmp.decoder.enabled  true
  10. Thankyou !
    I have been trying to look for a workaround since youtube stopped supporting flash. Some HTML5 works and some did not work and I don’t understand why that is. At least videos (at least the one I knew didn’t work), now work.
    I did add: media.gmp-eme-adobe.version 17 (String) as advised on the MSFN boards. I don’t know if that makes any difference. I should have done it in steps. Oh well.
    Thanks again for putting this info together with concise easy to follow instructions.

  11. […] von Mozilla Firefox liegt. Glücklicherweise hat der xp bouncer eine Lösung dafür gefunden: http://wp.xin.at/archives/4059 Herzlichen Dank auf diesem Wege, funktioniert […]

  12. For me this trick worked perfectly im on FireFox ESR 52.4.1 (32-bit) but now that trick stopped working on youtube html5 it shows i have html5 working its checked blue , but for example https://www.quirksmode.org/html5/tests/video.html i cant view H.264/MP4 test video , and many live streams on youtube i cant view , any help ? Thanks

    • Hello Jul1us,

      Did you update your browser? If yes, you may wish to examine the following properties on about:config and make sure they’re all set as follows, especially the 51.0 part in media.gmp-manager.url (if it says %VERSION% there, replace it!), but the others as well:

      media.mp4.enabled			true
      media.mediasource.mp4.enabled		true
      media.eme.enabled			true
      media.gmp-eme-adobe.enabled		true
      media.gmp-eme-adobe.forceSupported	true
      media.gmp-eme-adobe.version		17
      media.gmp-eme-adobe.visible		true
      media.gmp-manager.url			https://aus5.mozilla.org/update/3/GMP/51.0/%BUILD_ID%/%BUILD_TARGET%/%LOCALE%/%CHANNEL%/%OS_VERSION%/%DISTRIBUTION%/%DIS
      media.gmp.decoder.enabled		true
      media.gmp.decoder.enabled		true

      If that doesn’t work, you may also want to try the Cisco OpenH264 “injection” trick. See the following threads in the comment section here: [1] and [2]. If you try this, make sure the property media.gmp-gmpopenh264.enabled is set to true as well.

      Let me know whether you managed to make it work (or whether you didn’t)!

      • Hi thrawn,

        Like everyone else I thought I was doomed to not using YouTube with Firefox.
        I went through all the steps above. I had to create folders in the win XP \Application Data\Mozilla\Firefox\Profiles\\gmp-eme-adobe\17\ because the gmp-eme-adobe folder didn’t exist. I then downloaded the 3 files for gmp-eme-adobe-v17.7z and put them into the \17 folder that I had created.
        I next went to the URL about:config and had to add the 4 lines for media-eme-adobe- and enabled them as shown.
        Finally, I went into the media-gmp-manager.url and changed the %VERSION% to 51.0.
        The result…..nothing. I still get the error message when i try and play a YouTube video.
        BUT, when checking the FAQ link it now shows all 6 boxes with a blue check mark. The middle 2 for H.264 were previously marked red.
        I do get sound playing for the videos but no video.
        With all 6 boxes checked in blue I am at a loss. Do you have any other suggestions?

        • Hello Dave,

          I’m still not sure why this doesn’t work for some people. You’re saying that the YouTube HTML5 [test page] says you have everything up and running, but you still can’t play back video on YouTube?! I didn’t have that happen so far.

          What do the about:plugins and about:addons pages have to say about the state of the Primetime plugin?

          • This is what the “about:plugins has. I’m guessing this is right.

            OpenH264 Video Codec provided by Cisco Systems, Inc.

            File: 1.6
            Path: C:\Documents and Settings\user\Application Data\Mozilla\Firefox\Profiles\bb6pkkz9.default-1504269995468\gmp-gmpopenh264\1.6
            Version: 1.6
            State: Enabled
            This plugin is automatically installed by Mozilla to comply with the WebRTC specification and to enable WebRTC calls with devices that require the H.264 video codec. Visit http://www.openh264.org/ to view the codec source code and learn more about the implementation.

            MIME Type Description Suffixes
            Primetime Content Decryption Module provided by Adobe Systems, Incorporated

            File: 17
            Path: C:\Documents and Settings\user\Application Data\Mozilla\Firefox\Profiles\bb6pkkz9.default-1504269995468\gmp-eme-adobe\17
            Version: 17
            State: Enabled
            Play back protected web video.

            The “addons” have the YouTube flash player and an add blocker.

            Thanks thrawn,
            Dave Mason

            • How to make HTML5 H.264/AVC video work on Windows XP/XP x64 (using Firefox 52,5.3)
              Using XP x32 SP3 POSREADY Videos on Facebook didn t play.
              With your tutorial I could get them playing.

              Thanks a lot

              • You’re welcome! :)

                Actually, I had my own troubles with Facebook videos. They just wouldn’t play with Firefox ESR 52 on XP x64 or on Linux (where I have the same browser version). However, at some point in time, they just started to work, probably a few months back.

                The Facebook guys have probably changed something, though I’m not sure what exactly…

              • H.264 and MSE & H.264 showed up disabled in Youtubes HtML5 test page,
                Youtube videos played normal, but Facebook videos wouln t.
                Now all 6 videoformats show up enabled on Youtubes HtML5 test page..

            • So it’s indeed loaded. I was placing my bet on the plugin being disabled for some reason, but that doesn’t seem to be the case. I’m afraid that I’m pretty much out of ideas regarding your case. I simply don’t get why the Youtube HTML5 page would detect your setup correctly, but videos would still fail to play. Doesn’t make much sense.

              Ah, but you’re saying you have Adobe Flash installed as well? Maybe it’s interfering and/or not really working on XP anymore? My final idea would be to temporarily uninstall or disable Adobe Flash and retry playing videos on Youtube. With that, you’d force the browser to fall back to HTML5 video.

              • thrawn,

                Another genius solution! I disabled the flash player and I can now play YouTube videos. Although Adobe says we can have both flash and 264 and choose which one to use, not so with XP I guess,
                Whatever, I am now another happy video watcher.
                Dave Mason

                • Well, I wouldn’t exactly call it a “genius” solution :roll: and to be honest, I didn’t think this would actually do the trick… but hey, who cares if it works now!

                  I just hope you don’t need Adobe Flash for any other websites… Permanently having to switch it on and back off would be a nuisance. Or maybe there are good extensions for that if it’s required?

  13. “when using Firefox 52.x ESR instead of Firefox 51.x ESR”

    Ehhh, of course there was no FF 51 ESR, it skips 7 versions. 10, 17, 24, 31, 38, 45 and 52 for now.

    Got a cold a while ago. Stayed home, played a lot of silly hacked flash games (those with a screwed-up balance anyway). A lot of those things didn’t even work in 64 bit FF with 64 bit flash. It seems like 64 bit flash has been missing some things (too long ago to remember where I read that).
    I’ve been experimenting with pale moon portable in 32 bit and that worked quite well. I previously tried 32 bit FF, but that uses the same profile as the 64 bit version, which can cause a lot of problems.

  14. This tutorial is great! See this video. But Chrome natively supports H.264 on Windows XP (at least HTML5 videos worked without manipulating my OS or browser). But I have a problem, a protected DRM video does not play through Horizon.tv (similar to Netflix). Would anyone know to advise me? Complete video test on Horizon.tv with console reports on WinXP. The joke is that this service has worked from March through Chrome, but it’s no longer since October. Thanks! :)

    • Hello Brano,

      I’m aware that Adobe PrimeTime is supposed to give users not just H.264/AVC playback capabilities, but also DRM support (similar to Google Widevine in Chrome).

      PrimeTime DRM seems to be mostly broken by now, and unfortunately I’m not exactly sure why. Maybe it’s because of certain websites asking for different, newer encryption ciphers or something, I don’t know. If you check out [this test], it shows MPEG-DASH working with Apple HLS AES 128 on XP. But most commercial services won’t play their stuff anymore, and I assume it’s because of the aging cryptographic implementation in Adobe PrimeTime 17. Firefox has switched to Google Widevine for its DRM-providing library by now as well after all.

      Maybe the older Widevine in Chrome versions for XP also lacks certain cryptographic implementations to still be able to play all contents? It’s just baseless assumptions, but I don’t know what else would be the cause. The best thing would be to get a modern Widevine library to run on XP… but that’s maybe not so easy.

      Oh and I’ve looked at the second video as well, but the logs don’t tell me anything I could make something out of. Also, some lines I can’t read because of the language barrier (I’m literate only in English and German).

  15. Just to say, you’re a genius! Instructions I understood, and followed, and it flipping works! Thank you very much for making up for the deficiency that somehow found it’s way into Mozilla. Thanks, thanks, many thanks!

    I might explore this site more…

  16. Awesome tutorial ! Been struggling with a solution for this for ages. Thanks so much :)

  17. thrawn, it goes to your credit that you’re quite upfront about originally getting most of this information from MSFN, but I think you should also consider proactively letting the guys over there know about the workarounds they haven’t discovered yet, such as the OpenH264 folder trick. I think cooperation like that would benefit even more people.

    • Hello VF,

      It hasn’t even occurred to me to report back on the MSFN thread actually. Mostly because the additional tricks weren’t discovered by myself either, as other users commenting here have came up with them! Maybe I’ll take the time and compare the current state from MSFN with what was published here. I’d also need to give the individual users credit then. ;)

      I won’t promise anything though, as I’m actually a pretty lazy bastard these days. :roll:

      • I didn’t mean you should put in huge effort but like you could just mention that people have posted more workarounds here and give your link. I get it, I’m also lazy to join there but I thought you’re maybe a member already.

        • Aah.. well, I actually am, as I’m posting in the New Moon thread as well, even though my user account at MSFN is very new. I just wanted to thank the guy who did the Pale Moon ➪ New Moon port over there, roytam1 is his name.

          I’m probably still going to assemble the information from here and post it over there directly, instead of just linking to it, maybe next week. Don’t wanna make it look as if I’d be advertising my own website. ;)

  18. What about people who use Windows XP 32bit? Isn’t there an easier way to get html5 videos to play on websites?

    • Hello Michael,

      The modifications apply to both XP 32-bit as well as XP x64! It’s the same browser anyway, as Firefox ESR only comes in a 32-bit flavor on Windows (for now), whether you’re running 32-bit or not.

      However, if this hack is too complicated for you, may I recommend [New Moon] to you as well, like I have to [Thomas]? It’s a port of the Pale Moon browser which itself is a fork from an older version of Firefox.

      Getting VP8/VP9 and H.264/AVC videos play in HTML5 is really easy and also pretty fast with New Moon, as it relies on ffmpeg/libav instead of Adobe PrimeTime. Instructions to get it working can be found at the link above, it’s really easy, and New Moon is much faster as well. It does have the old, classic user interface though (Some people like that, some don’t). ;)

      Major drawback: It doesn’t and will never support the new WebExtensions. So you’ll get fewer original Firefox extensions to work than you would on an actual Firefox ESR. Some have been [ported over] to Pale Moon though. Besides that, some Extensions that are now WebExtensions can be downloaded in older versions for Pale Moon / New Moon, if that’s acceptable for you.

      Hope this helps!

  19. You advise manually putting properties in the about:config list as if is was just a mater of typing them in but I cannot find a way to so this.
    Your descriptions are excellent up to that point and then you seem to assume that adding elements to the about:config list is just a mater of typing it in. It aint so. It seems to require insider knowledge. This surprises me because of how well you seem to understand the problem (cant watch html5 content).

    • Hello savage,

      It is pretty much just a matter of typing them in. ;) But let me show you step by step:

      First, enter about:config into Firefox’ address bar, then press <enter>. That’s where you should receive the warning “This might void your warranty!”. Confirm the “I accept the risk!” part, and you should see the list of preferences and their values.

      To add a new preference, right-click anywhere in the list of preferences and values and pick “New”. You’ll be presented with a choice of three data types: “String”, “Integer” and “Boolean”. “String” means just text, “Integer” means integer numbers and “Boolean” means binary true / false values.

      What you may need to add here are “Boolean” preferences, so pick that one. It’ll ask you to “Enter the preference name:”. Here’s where you key in something like media.gmp-eme-adobe.visible. After that it’ll ask you to “Enter boolean value:”. For the examples above, the correct choice is true.

      Also: To edit an existing preference, just double-click it!

      That should do the trick! :)

  20. Silly question. I am running Win XP and FF 50.4.0 (32 bit) but don’t see:

    media.gmp-eme-adobe.enabled true
    media.gmp-eme-adobe.forceSupported true
    media.gmp-eme-adobe.visible true
    media.gmp.decoder.enabled true
    media.eme.enabled true
    media.mediasource.mp4.enabled true
    media.mp4.enabled true

    Please advise.

    • Sorry, that’s FF FF 52.4.0

      • Hello Victor,

        From the top: Open FF and visit the URL about:config, click on “I accept the risk”. Then start typing one of the field names in the search field on that page, and it should show you proper results below.

        It’s normal that some of those don’t exist yet. If they can’t be found, just create them; Right-click into a free space on the page, and select “New \ Boolean”. Enter the missing field name – like media.gmp-eme-adobe.enabled, and make sure it’s set to true. At least some values like media.mp4.enabled should already be there, though.

  21. Hats off to you Sir. Worked perfectly on my FF52.3.0 ESR and I can see HD again. I needed to do the 51.0 bit as well.

    • Hello Tom,

      Although I didn’t really come up with anything by myself, most of it is from the MSFN board, and the rest has been solved by the people commenting here. :) Seems like the %VERSION% => 51.0 change is really necessary in all cases for fresh installations of FF 52.x now.

  22. Hey thrawn. It’s really great that you put so much effort in this project and im pretty shure you are helping a lot of people. I was also looking for a solution for this problem and thought that now i have found one, or you have found one. I made everything as you described, sadly when i visit the quirksmode page it says that the primetime plugin crashed. its the same with some other players and some youtube videos.

    Maybe somebody has an idea, or had the same problem?

    • Hello Ulrich,

      Hmm, I’ve had Primetime crash before, but only very, very rarely, haven’t seen any crashes in months. The Quirksmode test page still works for me as well (Firefox 52.3.0).

      You say it’s only “some” videos that are causing this? Do you still have Adobe Flash installed as well? And could you post what the [Youtube HTML5] page reports?

      • Hello, thx for replying.

        Today i tried a couple of vids on youtube and everything went fine. The youtube HTML5 page has all checks.
        I have installed Flash Player 27.0.0.

        But again on the Quirksmode test page and on another page, when i want to watch a video, it says that primetime crashed.

        Could it be a problem that i first created the gmp-eme-adobe folder and afterwards i updated Firefox 47 to 52??

        Maybe i should deinstall firefox and go through the procedure again?

        • To be honest, people have been reporting issues when updating Firefox (including myself, although my issue was minor, as you can see in the article), but also when setting this up using the latest version 52 of the browser. It should be fixable in any case though!

          You could try to uninstall FF, and attempt a fresh installation of 52.3.0. However, to make it work in that scenario, some people had to “smuggle” the plugin in right under Firefoxes’ ass, by replacing Ciscos’ OpenH264 WebRTC plugin with it. The solution has been described in two comment threads right here: [1] and [2]. Another user has reported the plugin breaking because of the media.gmp-manager.url property value in about:config (also seen in the threads I just linked to). Replacing %VERSION% with 51.0 before checking for plugin updates worked for some users.

          So yeah, it seems that this can be tricky to get working, depending on your exact software setup. :( I just haven’t really tested all the possible scenarios, like fresh installations of newer versions or updating from versions older than the one I started with, etc.

  23. tanks fron brazil!!!

  24. Hello, I come across to your web page by accident and would like to record my sincere thanks for helping me to play html5 video on my xp system using firefox 51.0.1 I can’t say how happy I am finally able to play html5 video after much frustration!

  25. BEAUTIFUL JOB explaining the mod, worked for me the first time (after manually enabling the dll and getting past “shortly”). WinXP32SP3. Held out with Youtube Flash for as long as possible then a lot just went dark. Been looking for awhile now… for me getting H.264 working was “the last straw”. For most people that means giving up but for me it means something different… it was the “last straw” required to get my XP32SP3 running with everything I need it to run… so I can go ANOTHER TEN YEARS without having to join the post-XP MSFT ‘F’ U Choo Choo (though I will try 7×64 on another machine and might migrate to it). I use a Win10 laptop for work and detest it.

    • Hello HocusLocus,

      “Another ten years” might be a bit too much I guess. ;) But I do share your resentment towards Windows 10, I have a Convertible set up with Win10 myself, and I do hate it (the OS, the machine is somewhat ok).

      Luckily, at work I’m in contact with Linux machines mostly, so customizing the GUI and its workflows is easier. Also, I do give users the opportunity to pick an environment of their choice, so everybody can feel a bit more “at home”. I do have to take care of a bunch of Win7 machines as well, but only for administration, so it’s fine.

      Personally, I’m still planning to migrate to some Linux or a BSD UNIX when the time comes to finally drop XP x64. Although I’ll likely keep an extra machine set up with modern MS Windows, just in case I go back to playing some games.

      • Hi again I’ve got a bizarre one for you but if you’re sick of hearing about this whole thing by now I would understand. Experienced general profile rot and *this time* went back to a fresh FF 47.0 (XP32bSP3), my ‘post-apocalypse’ platform for various reasons. The steps which worked for my v48 didn’t work, all the boolean config keys were there and the gmp-eme-adobe\17\ folder, but “Primetime” did not appear in the plugin list. PROCMON trace showed it wasn’t even accessing the folder. Though it was loading gmpopenh264.dll.

        I was in no mood to trifle today and don’t care about WebRTC… so in the gmp-gmpopenh264\1.6\ folder I copied eme-adobe.dll OVER gmpopenh264.dll and eme-adobe.info OVER gmpopenh264.info. Primetime still doesn’t show up on the list but something under the hood changed… H.264 works. Hope to win prize for ugliest solution.

    • Thanks to all for their contributions to this thread. If you are able to make this work please help your family and friends who think they need to dump their XP machine for a new one that plays their favorite videos. The clear instructions here worked for me on XP Home v2002 SP3 with Firefox 52.3.0 and no doubt would save many otherwise perfectly good Windows XP PCs from being sent to the recycling bin.

      • Hey Kyle!

        I hadn’t even looked at this whole thing from that point of view. Usually, for my family, I’d just give their old machines a Linux distribution as slim and classic as possible. Then they can have all the modern software they want (for accessing the web).

        But hey, if this guide can save a few old PCs, then it’s a good thing, as long as those machines don’t turn into spambots because of some malware. ;) I would’ve just thought that people would rather install a new or different OS instead of throwing away the entire machine?! But I guess that’s not how people do it nowadays? :roll:

  26. THX alot for the info’s here..
    updted my win-Xp with fireox and my notebook with FirefoxPortable
    update your FirefoxPortable to 52.3.0 (today)
    then, here the path is C:\Programme\FirefoxPortable\Data\profile\gmp-eme-adobe\17\
    with the three files, see above…
    i’m german, so the path is a bit different, mybe Programme = Programs ; and change driveletter you have…
    and make sure on FirefoxPortable profile folder is here not “profiles” only profile …
    it works here, so i have all seven blue checkboxes ok, with white hook’s in…
    thanks again.. nice info..

    • oh i forgot:
      – update firefox with internal update-button..

      – the seven checkboxes are here: https://www.youtube.com/html5

      • Hey Rio71,

        So you had an older version before 52.3.0, and updated to the latest ESR version? In that case it usually works fine. It seems that the people who have had some trouble with this solution were the ones who did a completely fresh installation of Firefox 52.3.0.

        Gosh, I didn’t even know that there was a portable version of Firefox…

  27. Thank you very much. I’m forced to use my old PC which only runs Win XP and this is working perfectly for me. I just wonder how long :P

    • Hey Arkunos,

      Who knows… But chances are it’s gonna work for at least a few years, as long as there are no significant changes to the codec suite currectly supported by HTML5 <video> and <audio>. Currently, we have stuff like H.264/AVC, Theora VP8/VP9, AAC-LC, mp3, FLAC, all of which are supported.

      The bigger problem will be DRM protected video, like on Netflix, Amazon Prime etc. Adobe PrimeTime is supposed to handle all that just fine, but it seems that it’s mostly broken on Windows XP. Maybe because XP is not a trusted operating system or something. So you shouldn’t count on any DRM video or audio to work with this solution. :(

  28. Hey, just followed your guide and the video works great but no audio :///
    any idea where i can tinker to try to get audio on again ?

    • Hello bemarchiori,

      Unfortunately, I have no idea. There are a variety of possible reasons for this, like Firefox being [specifically muted] by the Windows volume mixer, a graphics cards’ HDMI audio interfering (you could try to hook up a TV to the graphics card via HDMI to see whether it plays the sound), or some part of your speaker configuration being [incompatible] with the HTML5 implementation of Firefox.

      Another issue might be that for some reason Firefox fails to play back certain audio encoding formats like maybe .mp3 or .opus or something. To test whether all formats work, you can try them [on this website]. If you can single out a specific audio format that doesn’t work, it’ll make debugging easier.

      I don’t have any experience with audio problems in the browser myself however, as it just works™ for me, so it’s hard to say. You could also try and look at the about:config directives dom.webaudio.enabled, dom.audiochannel.mutedByDefault or media.mediasource.webm.audio.enabled, but that’s just me reading the tea leaves…

  29. Hey Mr. Thrawn. Many, many thanks for your help. In my Windows XP SP3 PC html5 videos work fine after changes according to your instructions. Best work of you. Beautiful. I’d like to add that I had (in about:config) to replace %VERSION% in media.gmp-manager.url to 51.0 before checking for updates, as Newb in his comment remarks.

  30. Huge thanks for this tutorial! It solved the problem of getting H.264 to work in Firefox for me. I’d like to note that if one is freshly installing Adobe Primetime in the latest version of Firefox ESR, they have to replace %VERSION% in media.gmp-manager.url to 51.0 before checking for updates. Then the update will work and H.264 will start working fine.

    • Hey Newb ( :roll: ),

      Thanks for the advice regarding fresh installations on newer versions of FF! :) I usually never check that stuff out, because I just keep my existing machines and VMs running, rarely setting up a new XP or XP x64 machine these days…

    • Hello everyone,
      One of my XP machines stopped playing HTML 5 Youtube videos a week or so back, I thought it
      was specific to that machine, then a second XP machine stopped just this evening August 9, 2017.
      So after much searching through various resources and trying a number of Firefox add-ons, I wasn’t
      having a lot of luck until I hit this page, hence the reason I’m posting a follow up here. My XP Firefox
      version is the latest 52.3.0 and the fix that worked for me was two fold, the first part I’m not sure was
      required, but I like what worked out so I’m very happy to be able to see HTML 5 Videos with Firefox
      on an XP 32 bit machine.

      First I uninstalled Adobe flash, required to upgrade it to the latest as just posted on the below
      SDFOX7 web page (thank you very much!) “Adobe Flash has been released. Tested
      and working on Windows XP SP3”

      Old version uninstaller: https://fpdownload.macromedia.com/pub/labs/flashruntimes/flashplayer/uninstall_flash_player.exe



      At this point you should have the latest verified XP Adobe Flash Player Installed.

      I then chased down the H.264 information to learn about HTML5 video support in Firefox on
      Windows XP using the Primetime Content Decryption Module plugin by Adobe (distributed
      by Mozilla). You can download the mentioned from a URL link provided in the article on the
      below web page.


      I followed the instructions to install and activate the plug in per the above web page.

      To install the plugin:
      Open your FF profile folder. An easy way to navigate to it is by opening about:support in FF
      and clicking the Open Folder button next to Profile Folder.
      Inside the profile folder, create subfolder gmp-eme-adobe and open it.
      Inside gmp-eme-adobe, create subfolder 17 and open it.
      Unpack the Primetime ZIP archive into folder 17.

      Which of course didn’t work as described… then using some information from this web page I
      simply moved the above extracted and installed (as directed above) adobe folder contents in
      to the existing gmp-gmpopenh264 1.6 folder after moving the original 1.6 folder contents to a
      same directory new folder of 1.6a.

      Restarted Firefox, done, works great!

      Might not be the most practical solution, but I’m all about what works well for me. Hope you
      have the same results.



      skipp025 at ya who period calm


      • Hello skipp025,

        Interesting, so you’re the second person to place PrimeTime into gmp-gmpopenh264\1.6\ instead of gmp-eme-adobe\17\ and get it working like that.

        Still sounds a bit wrong to me to “abuse” Ciscos’ OpenH264 folder like that, but if it works… Yeah, why not. I still have it sit in the gmp-eme-adobe\17\ folder with everything working fine, so I’ll just leave it like that. Oh, and I’m on Firefox ESR 52.3.0 by now.

        Nice boat btw. ;)

      • your html5 install worked, but its still playing in 360 for the most part.
        is there a way to get all videos to hd? of course i also am using firefox in xp 32 bit as well…

      • now, even after installation and placing it in folder 1.6, i came across a youtube video with the old “your browser does not currently recognize…”
        sad day :(

  31. No way… I’ve just follow all your instructions, but, at the end always appears a notice saying that Primetime it’s going to be “installed shortly”.
    If I click on “check updates”, then in: \Mozilla\Firefox\Profiles\\ appears a new folder “gmp-gmpopenh264”>1.6 containing “gmpopenh264.dll” and “gmpopenh264.info”

    My current Firefox version is 51.0.1, and using Windows XP (32bits) now. Please, can you help me? Any idea would be good! Thanks.

    • Evening, Pierre!

      Well, since I’m pretty drunk right now, I’d rather refrain from trying to solve this for you at this time. ;) Maybe I’ll look into it tomorrow. Seems like you just need to quit FF and install the files manually though, hm. The openh264 stuff is completely useless anyway (it won’t decode Streams, it’s for WebRTC only)…

      Ah, I’ll look into it tomorrow, if I have the time… ‘yasumi…

      • I have solved it myself; after click in “check updates” (about:addons> Adobe Primetime) FF automatically creates me “gmp-gmpopenh264” folder.
        I’ve downloaded your “gmp-eme-adobe” files, and changed “17” to “1.7”! Then I’ve put it inside “gmp-gmpopenh264” folder, click again in “check updates” and… Voilà! Everything works now.

        You’re a fantastic person! Thanks for being willing to help me… Your website is great!

        • Hoh… That’s an… interesting way to make it work. I mean, I do have OpenH264 installed, but in that folder, there are only the Cisco OpenH264 files, as one would expect. There are two folders:

          %USERPROFILE%\Application Data\Mozilla\Firefox\Profiles\\gmp-gmpopenh264\1.1
          %USERPROFILE%\Application Data\Mozilla\Firefox\Profiles\

          Each folder contains two files, gmpopenh264.dll and gmpopenh264.info. When opening the latter in a text editor, it shows this (e.g. for the 1.6 version):

          Name: gmpopenh264
          Description: GMP Plugin for OpenH264.
          Version: 1.6.0
          APIs: encode-video[h264], decode-video[h264]

          So this clearly doesn’t have anything to do with Adobe Primetime. It seems you got PrimeTime to load from within Ciscos’ OpenH264 folder? Sounds reeeally strange, but if it works… should be fine I guess. ;)

          By the way, the info file for PrimeTime – eme-adobe.info – shows this:

          Name: Primetime Content Decryption Module provided by Adobe Systems, Incorporated
          Description: Provides support for playing back protected web video
          Version: 17
          APIs: decode-video[com.adobe.primetime:h264], decode-audio[com.adobe.primetime:aac], eme-decrypt-v7[com.adobe.primetime]
          Libraries: dxva2.dll

          Heh, both say that they support the decode-video[h264] API, I wonder why we can’t use Ciscos’ stuff to just decode H.264/AVC on Youtube or elsewhere…

          • At first, thanks for this great guide! Running it on the ever worsening Firefox bloatware in it’s V45.9 decline (as my CustomButtons scripts are – what else – broken again with higher versions), I would like to add the cause for this “check updates” message. As stated above, the eme-adobe.info demands the dxva2.dll HW acceleration library, usually located at Windows\System32. If not available, f. i. while restraining web access to a VM, the browser seems to wait for it. So just delete that line from the info file and the plugin will load fine.

            Hope this helps some people who are also not willing to throw many years of xp experience, customization and all the paid progs to the bin :-)

            • Hey Thomas,

              Ah, interesting, thanks for that! Of course, XP only comes with the older DXVA1. Off-topic: I’m extremely happy that the MPC-HC media player supports it for hardware acceleration on XP. ;)

              On a side-note: I’ve dropped Firefox for now, and I’m going with a fork of it: “New Moon”. That in itself is a Windows XP-specific fork of Pale Moon in its latest version. You can find New Moon [here]. There are 32- and 64-bit builds for both classic Windows XP NT 5.1 and XP x64 / Server 2003 NT 5.2 (I’m using the 64-bit one).

              It doesn’t bring some of Firefox’ features to the table (like Electrolysis or Web Extensions), so there are a lot of extensions it can’t handle. Some have been [ported over] though.

              My primary reason for switching: Pale Moon / New Moon is just much faster, less bloated! And it may outlive Firefox ESR 52 on Windows XP, security-wise. Maybe you want to look at that browser as well. HTML5+H.264 is even easier with New Moon than it is with Firefox, as it relies on ffmpeg/libav libraries to play back H.264, much like some Firefox installations on Linux do. :)

              • Sorry to say my conclusion regarding dxva2.dll isn’t true, it also works with this default entry.

                The message “will be installed shortly” appears to wait for its update-check as described at msfn. If the about:config preference media.gmp-manager.url is emptied, this update-check just never happens. Filling in https://aus5.mozilla.org/update/3/GMP/46.0/%BUILD_ID%/%BUILD_TARGET%/%LOCALE%/%CHANNEL%/%OS_VERSION%/%DISTRIBUTION%/%DISTRIBUTION_VERSION%/update.xml (note version 46.0 – using 45.9 while running v45.9 didn’t work) and clicking the check for updates link removes this “installed shortly” message after a few seconds and YT confirms all six formats.

                As I prefer web-connections only via virtual machines their performance won’t be sufficient for HD SW-decoding and I just download them for host playback with, yes, MPC-HC and DXVA on embedded nVidia chipset- or AMD A10-graphics :)

                Didin’t know of New Moon and felt quite uneasy to switch to other mainstream browsers by now, so this sounds great! Wouldn’t need Web Extensions with another set of broken addons and multi-processing may be of no avail on VMs. I surely will give it a try in time, thanks for the hint.

                • On the latest versions of FF ESR, “…/GMP/46.0/%BU…” is replaced by “…/GMP/%VERSION%/%BU…” which stops this step from working, presumably because there are no more versions available to download? Changing this back to “46.0” re-enables this file to be downloaded which finally gets rid of “will be installed shortly” message. A dirty hack, but then this whole thing is! Thanks to everyone for finding it and for your added updates guys!

  32. Thank your for the article, I just follow the instructions and have remotely fixed my father’s old XP computer.

  33. Wasn’t adobe primetime removed for some reason? I do remember reading about it being already old hat, or something.

    • It’s been replaced with Google Widevine recently for Firefox as well, yes. My version 53.0.2 on Windows 7’s already using it. Problem is, Widevine just won’t work on Firefox 52 ESR on XP x64, and I have no idea why. I even checked the headers of the widevinecdm.dll, but it says it’s compiled for NT5.1, so XP 32-bit. No idea.

      FireFox 52 ESR still comes with Adobe PrimeTime on Windows anyway, and it’s the only solution I know of that’s working at all. Just needs a bit of persuasion to load. Maybe somebody can shed some light on why Widevine refuses to run? My FF configuration on about:config is identical on both Win7 and XP x64 and it’s the same Widevine version as well… Maybe Widevine just refuses to load in FF 52 ESR?!

      • I really don’t think my 52 ESR came with adobe primetime. I’d have to check a fresh-installed pc-for-home, because my settings at work turn off all that drm.

        There was no XP x64 N version, otherwise I would look there. XP N was great, but W7 N has stupid issues. You can’t install the windows mobile sync software because of missing media shite. Great. Netflix doesn’t work in firefox because of missing media features.

        Have you tried this program? http://www.dependencywalker.com/
        I uhhh, I don’t have any XP x64 in the house any more. I replaced my computer at work just two weeks ago. Some things are better, some things just suck with W7. And W7 is even hard to install with a recent motherboard. Only xhci (usb3), nvme drive, etc.

        • I’ve used Dependency Walker before, but not for this problem, no. I probably should, huh?

          Also, it might be that FF52 ESR didn’t come with Adobe Primetime, but it can be downloaded independently and made to work with the browser just fine. Huh, guess I should’ve provided a download link for that, eh? Well, it’s almost 1am now, so… no! ;)

        • Hey again,

          Alright, I ran the 32-bit widevinecdm.dll through both the 32-bit as well as the 64-bit Dependency Walker in version 2.2.6000 on Windows 7 x64 (where Widevine works) as well as XP x64 (where it does not). I am using a 32-bit version of Firefox on both systems and as said, the FF configurations related to Widevine are identical. The XP x64 version of FF also has Adobe Primetime up and running, which shouldn’t hurt.

          I’ve exported the outputs as .dwi images as well as .csv files for you to read, and I’ve also attached the Widevine library I’m using for this, it’s version Here are the files:

          In essence, what I got was this:

          Windows 7 x64 SP1:

          Missing files:

          • API-MS-WIN-CORE-WINRT-L1-1-0.DLL
          • DCOMP.DLL
          • GPSVC.DLL (Only with 32-bit DW)
          • IESHIMS.DLL

          Errors & warnings:

          Error: Modules with different CPU types were found. (Only with 64-bit DW)
          Warning: At least one delay-load dependency module was not found.
          Warning: At least one module has an unresolved import due to a missing export function in a delay-load dependent module.

          Windows XP Professional x64 Edition SP2:

          Missing files:

          • DEVMGR.DLL (Only with 32-bit DW)
          • IESHIMS.DLL
          • WER.DLL

          Errors & warnings:

          Error: Modules with different CPU types were found. (Only with 64-bit DW)
          Warning: At least one delay-load dependency module was not found.
          Warning: At least one module has an unresolved import due to a missing export function in a delay-load dependent module.

          Maybe you can make something of all this?

          • I thought you were the expert :-p

            Almost every file I tried is missing the ieshims.dll, so that’s probably nothing. I don’t think there’s anything missing on this level. It could be loads of things. Loose guesses: DirectX 9, .net lamework 3.5 (only needed for the evr.dll, that enhanced video renderer). Uhm, not a great help, eh? ;-)

            • Pfh, no idea. It seems Win7 is missing even more stuff than XP x64?! ;)

              Well, DEVMGR.DLL is a library for accessing the Windows device manager, not sure why Widevine would want that?! Maybe to look for a GPU / hardware video decoder? The weird thing: My VM doesn’t have that file, but my native XP x64 workstation does. I just copied it over, and DW now doesn’t report it as missing any longer, but its a bitness mismatch. I only seem to have a 64-bit version of this library, nothing in %WINDIR%\SysWOW64\.

              Ok, so I copied it from a 32-bit XP / POSReady2009 machine, and put it right next to widevinecdm.dll, which stops the complaining. Links properly it seems.

              Still, that didn’t do the trick at all. The other two libraries are for Internet Explorer shims and Windows error reporting for Vista+, and one of them depends on ncrypt.dll which itself depends on bcrypt.dll, both of which require API functions simply not present on XP / XP x64 (I just tried it with the 32-bit Vista DLLs). And WER.DLL is the same. The whole modern error reporting system just isn’t there after all.

              And here’s where I’m gonna stop, I think that’s a really good point to stop trying! ;) :roll:

            • Hmm, instead of the Widevine Content Decryption Module I tried the Widevine Media Optimizer instead, from the [Widevine website], accessing the site with FF on Windows. Since the codesigning signature of the plugin is somehow not right, you can’t install it (Firefox says it’s “corrupted”) right away, but that can easily be circumvented. By changing the following flags on about:config, as shown:

              xpinstall.signatures.required  [boolean]  false
              xpinstall.whitelist.required   [boolean]  false

              With those set to false, the Widevine Media Optimizer can be installed from there, and its npwidevinemediaoptimizer.dll does load, showing version But it doesn’t seem to play any H.264/AVC at all, nor will it decrypt any HLS or MPEG-DASH stuff (which PrimeTime partially can do on XP). I’m not even sure what it is that it’s doing. It’s supposed to support video playback as well, but I dunno… No luck with that either.

  34. Is there also a way to activate Google Widevine CDM in firefox on Windows XP?

    • I haven’t found any yet. The XPI extension from [Widevine] itself just fails to install because it’s too old, and Google never allowed the installation of Widevine on XP in the first place, at least not to my knowledge. I do not know if the plugin really contains code that won’t work on XP, but yeah… What I tried was this:

      • Download a later Widevine version from Mozilla: [Source]. (version
      • Unpack the files into %APPDATA%\Mozilla\Firefox\Profiles\\gmp-widevinecdm\\, creating the folders that do not yet exist along the way.
      • Set up the following properties on the about:config page:
        • media.gmp-widevinecdm.abi [string]      x86-msvc-x64
        • media.gmp-widevinecdm.enabled [bool]    true
        • media.gmp-widevinecdm.lastUpdate [int]  1485441970
        • media.gmp-widevinecdm.version [string]
        • media.gmp-widevinecdm.visible [bool]    true

      All to no avail unfortunately. I never got that widevinecdm.dll to load and show in Firefox… :( Maybe I’m just doing something wrong, not sure…

  35. Thanks a lot! Works great with FF 47 (32 bit) on XP64.

    • Hello nnm,

      Ah yes, from what I heard, FF 47 was the first to have unofficial support for Adobe Primetime. Good to see I wasn’t mistaken regarding that. But: I didn’t come up with that solution, so no need to thank me. Thank the guys at [MSFN]! :)

      By the way, out of curiosity, how did you find my post? This shouldn’t be ranked highly in any search engine or anything…

      • Found by googeling on firefox and XP64, then I’ve seen the title in “Recent Posts”. I tryed and to my surprise it just worked. I was looking for a solution for this problem for long time. Until now I was using Greasemonkey scripts to convert video tags to embed, but was error prone, and plugin support will be gone soon.
        Anyway, great site, bookmarked since I have no intention to upgrade to Windows 10.

        • Ah, I see.. I guess Google does give different kinds of results to different people. Well, I’m always happy to help! :)

          I’ll continue using XP x64 myself for a while (My workstation will never see a Windows 10 installation), besides the Linux and UNIX OSes. So everytime I discover something useful, I’ll share it here. Even if it’s actually somebody elses’ discovery. :P

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