Solved Firefox won't play twitter videos

[randomwin7user]

I've had this problem for a while now where twitter won't play videos. All I see the first frame of the video and an error message that says "This browser does not support video playback."

 

[FerchogtX]

Look under about:support page (type about:support in adress bar), copy data to clipboard and post it here, probably, H264 Hardware accelerated decoding is not enabled in your system...

 

[randomwin7user]

Application Basics
------------------

Name: Firefox
Version: 44.0.2
Build ID: 20160210153822
Update Channel: release
User Agent: Mozilla/5.0 (Windows NT 5.1; rv:40.0) Gecko/20100101 Firefox/44.0.2
Multiprocess Windows: 0/2 (default: false)
Safe Mode: false

Crash Reports for the Last 3 Days
---------------------------------

Report ID: bp-aa417f26-053f-44cb-9ecc-4e0972160312
Submitted: 2 hours ago

All Crash Reports

Extensions
----------

Name: Adblock Plus
Version: 2.7.2
Enabled: true
ID: {d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}

Name: DownThemAll!
Version: 2.0.18.1-signed.1-let-fixed
Enabled: true
ID: {DDC359D1-844A-42a7-9AA1-88A850A938A8}

Name: Element Hiding Helper for Adblock Plus
Version: 1.3.7
Enabled: true
ID: [email protected]

Name: Hide Unwanted Results of Google Search
Version: 1.6
Enabled: true
ID: jid0-TpZJ4wPImlT1zIqfw58bD9vOeWQ@jetpack

Name: Video DownloadHelper
Version: 5.5.0a16
Enabled: true
ID: {b9db16a4-6edc-47ec-a1f4-b86292ed211d}

Name: VLC Youtube Shortcut
Version: 0.8.2.0
Enabled: true
ID: [email protected]

Name: YouTube™ Flash® Player
Version: 1.6.2
Enabled: true
ID: jid1-HAV2inXAnQPIeA@jetpack

Name: Microsoft .NET Framework Assistant
Version: 1.0
Enabled: false
ID: {20a82645-c095-46ed-80e3-08825760534b}

Graphics
--------

Adapter Description: ATI Mobility Radeon X1600
Adapter Drivers: ati2dvag
Adapter RAM: Unknown
Asynchronous Pan/Zoom: none
Device ID: 0x71c5
Direct2D Enabled: Blocked for your graphics driver version. Try updating your graphics driver to version 9.6 or newer.
DirectWrite Enabled: false (0.0.0.0)
Driver Date: 2-13-2009
Driver Version: 8.590.0.0
GPU #2 Active: false
GPU Accelerated Windows: 2/2 Direct3D 9 (OMTC)
Subsys ID: 30a3103c
Supports Hardware H264 Decoding: No; Failed to create H264 decoder
Vendor ID: 0x1002
WebGL Renderer: Google Inc. -- ANGLE (ATI Mobility Radeon X1600 Direct3D9 vs_3_0 ps_3_0)
windowLayerManagerRemote: true
AzureCanvasBackend: skia
AzureContentBackend: cairo
AzureFallbackCanvasBackend: cairo
AzureSkiaAccelerated: 0

Important Modified Preferences
------------------------------

accessibility.typeaheadfind.flashBar: 0
browser.cache.disk.capacity: 235520
browser.cache.disk.filesystem_reported: 1
browser.cache.disk.hashstats_reported: 1
browser.cache.disk.smart_size.first_run: false
browser.cache.frecency_experiment: 2
browser.download.importedFromSqlite: true
browser.download.manager.alertOnEXEOpen: false
browser.places.smartBookmarksVersion: 7
browser.search.useDBForOrder: true
browser.sessionstore.upgradeBackup.latestBuildID: 20160210153822
browser.startup.homepage: Google
browser.startup.homepage_override.buildID: 20160210153822
browser.startup.homepage_override.mstone: 44.0.2
browser.tabs.remote.disabled-for-a11y: true
dom.apps.reset-permissions: true
dom.mozApps.used: true
extensions.lastAppVersion: 44.0.2
font.internaluseonly.changed: false
general.useragent.override: Mozilla/5.0 (Windows NT 5.1; rv:40.0) Gecko/20100101 Firefox/44.0.2
gfx.crash-guard.d3d11layers.appVersion: 44.0.2
gfx.crash-guard.d3d11layers.deviceID: 0x71c5
gfx.crash-guard.d3d11layers.driverVersion: 8.590.0.0
gfx.crash-guard.d3d11layers.feature-d2d: false
gfx.crash-guard.d3d11layers.feature-d3d11: false
gfx.crash-guard.glcontext.gfx.driver-init.direct3d11-angle: false
gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle: false
gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-force-d3d11: false
gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-force-warp: false
gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-try-d3d11: true
gfx.crash-guard.status.d3d11layers: 2
gfx.crash-guard.status.glcontext: 2
gfx.driver-init.appVersion: 42.0
gfx.driver-init.deviceID: 0x71c5
gfx.driver-init.driverVersion: 8.593.0.0
gfx.driver-init.feature-d2d: false
gfx.driver-init.feature-d3d11: false
gfx.driver-init.status: 2
layers.acceleration.force-enabled: true
media.gmp-gmpopenh264.abi: x86-msvc-x86
media.gmp-gmpopenh264.lastUpdate: 1454445720
media.gmp-gmpopenh264.version: 1.5.3
media.gmp-manager.buildID: 20160210153822
media.gmp-manager.lastCheck: 1457740884
media.hardware-video-decoding.failed: true
media.mediasource.webm.audio.enabled: true
media.mediasource.webm.enabled: true
media.webrtc.debug.aec_log_dir: E:\DOCUME~1\User\LOCALS~1\Temp
media.webrtc.debug.log_file: E:\DOCUME~1\User\LOCALS~1\Temp\WebRTC.log
network.cookie.prefsMigrated: true
network.predictor.cleaned-up: true
places.database.lastMaintenance: 1457741062
places.history.expiration.transient_current_max_pages: 13504
plugin.disable_full_page_plugin_for_types: application/pdf
plugin.importedState: true
print.printer_Microsoft_XPS_Document_Writer.print_bgcolor: false
print.printer_Microsoft_XPS_Document_Writer.print_bgimages: false
print.printer_Microsoft_XPS_Document_Writer.print_duplex: -437918235
print.printer_Microsoft_XPS_Document_Writer.print_edge_bottom: 0
print.printer_Microsoft_XPS_Document_Writer.print_edge_left: 0
print.printer_Microsoft_XPS_Document_Writer.print_edge_right: 0
print.printer_Microsoft_XPS_Document_Writer.print_edge_top: 0
print.printer_Microsoft_XPS_Document_Writer.print_evenpages: true
print.printer_Microsoft_XPS_Document_Writer.print_footercenter:
print.printer_Microsoft_XPS_Document_Writer.print_footerleft: &PT
print.printer_Microsoft_XPS_Document_Writer.print_footerright: &D
print.printer_Microsoft_XPS_Document_Writer.print_headercenter:
print.printer_Microsoft_XPS_Document_Writer.print_headerleft: &T
print.printer_Microsoft_XPS_Document_Writer.print_headerright: &U
print.printer_Microsoft_XPS_Document_Writer.print_in_color: true
print.printer_Microsoft_XPS_Document_Writer.print_margin_bottom: 0.5
print.printer_Microsoft_XPS_Document_Writer.print_margin_left: 0.5
print.printer_Microsoft_XPS_Document_Writer.print_margin_right: 0.5
print.printer_Microsoft_XPS_Document_Writer.print_margin_top: 0.5
print.printer_Microsoft_XPS_Document_Writer.print_oddpages: true
print.printer_Microsoft_XPS_Document_Writer.print_orientation: 0
print.printer_Microsoft_XPS_Document_Writer.print_page_delay: 50
print.printer_Microsoft_XPS_Document_Writer.print_paper_data: 1
print.printer_Microsoft_XPS_Document_Writer.print_paper_height: 11.00
print.printer_Microsoft_XPS_Document_Writer.print_paper_name:
print.printer_Microsoft_XPS_Document_Writer.print_paper_size_type: 0
print.printer_Microsoft_XPS_Document_Writer.print_paper_size_unit: 0
print.printer_Microsoft_XPS_Document_Writer.print_paper_width: 8.50
print.printer_Microsoft_XPS_Document_Writer.print_resolution: -437918235
print.printer_Microsoft_XPS_Document_Writer.print_reversed: false
print.printer_Microsoft_XPS_Document_Writer.print_scaling: 1.00
print.printer_Microsoft_XPS_Document_Writer.print_shrink_to_fit: true
print.printer_Microsoft_XPS_Document_Writer.print_to_file: false
print.printer_Microsoft_XPS_Document_Writer.print_unwriteable_margin_bottom: 0
print.printer_Microsoft_XPS_Document_Writer.print_unwriteable_margin_left: 0
print.printer_Microsoft_XPS_Document_Writer.print_unwriteable_margin_right: 0
print.printer_Microsoft_XPS_Document_Writer.print_unwriteable_margin_top: 0
privacy.cpd.offlineApps: true
privacy.cpd.siteSettings: true
privacy.donottrackheader.enabled: true
privacy.sanitize.migrateClearSavedPwdsOnExit: true
privacy.sanitize.migrateFx3Prefs: true
storage.vacuum.last.index: 1
storage.vacuum.last.places.sqlite: 1455419324
webgl.force-enabled: true

Important Locked Preferences
----------------------------

JavaScript
----------

Incremental GC: true

Accessibility
-------------

Activated: false
Prevent Accessibility: 0

Library Versions
----------------

NSPR
Expected minimum version: 4.11
Version in use: 4.11

NSS
Expected minimum version: 3.21 Basic ECC
Version in use: 3.21 Basic ECC

NSSSMIME
Expected minimum version: 3.21 Basic ECC
Version in use: 3.21 Basic ECC

NSSSSL
Expected minimum version: 3.21 Basic ECC
Version in use: 3.21 Basic ECC

NSSUTIL
Expected minimum version: 3.21
Version in use: 3.21

Experimental Features
---------------------

 

[FerchogtX]

Well, from what I see, Direct2D is disabled, so no hardware accelerated layers or cleartype is enabled, also, H264 decoding is disabled as well. You driver is from 2009 which could explain why those features are disabled. Try updating your drivers from here Download Drivers using the automatic detection tool, there should be at least a 2010 driver for you, which should enable at least hardware acceleration for the main browser thread (therefore, accelerating your browsing experience).

If you happen to update your drivers to the latest version (at least superior than the 2009 one you currently have) and H264 decoding is still blacklisted for your GPU, look for media.hardware-video-decoding.failed: true in about:config page and set that to false, restarting your browser afterwards.

If this last works for you, Firefox could revert this setting back if any update is available, in that case, you can always create a user.js file with this pasted into it:

user_pref("media.hardware-video-decoding.failed", false);

and saved in the same place your profile files are located (typicaly C:\Users\[Your Username]\AppData\Roaming\Mozilla\Firefox\Profiles\[Your Profile or xxxxx.default if you use FF defaults]
This way you will always override Firefox GPU detection.
(I leave the file zipped with the pref for a quick use in case you need it)

But first, try updating your drivers, 2009 drvers for any AMD card are known for being blacklisted and being problematic with Firefox, I had to do that with my HD 3200 card...

Hope this helps you

 

[randomwin7user]

I enabled direct2d, H264 decoding and my graphics card drivers are the latest that the computer manufacturer made and twitter videos still won't play. and windows says that the autodetect utility isn't a valid win32 application.

 

[FerchogtX]

That's weird...
Try the autodetect utility from this zip file, it should work, taking in mind you mention in your specs your OS is 64 bit Home Basic...
Let me know if this worked, if the same error appears, I suggest to backup your bookmarks, go to about:support and click on "Refresh Firefox", also, do a full AV scan to your PC, with your preffered AV software, but also with Malwarebytes AntiMalware Free, just to discard you didn't catch an infection over your system (that "not valid win32..." error is suspicious...)

 

[randomwin7user]

winrar gives me this message Cannot execute "C:\DOCUME~1\User\LOCALS~1\Temp\Rar$EXa0.807\autodetectutility.exe"
windows gives me this message C:\Documents and Settings\User\Desktop\autodetectutility.exe is not a valid Win32 application
command prompt gives me this message "C:\Documents and Settings\User\Desktop\autodetectutility.exe" Access is denied

 

[FerchogtX]

Are you using an Administrator account (I mean, any account that is an administrator, not the admin account itself)? Looks like a Basic account limitation...

 

[randomwin7user]

No, I'm an admin

 

[FerchogtX]

Run a full AV scan on your system, also, get Malwarebytes Free, install, and run a full scan on your system.

I feel you got malware issues, not being able to run setup executables feels suspicious to me...

P.S. Don't worry about the trial thing, that only enables realtime protection and extra settings, manual scan and removal tools will be still there.

 

[randomwin7user]

I'm positive it's not a virus because I can run every other executable I can find

 

[GEWB]

Problem is with mommy Mozilla trying to protect you. If you visit MozillaZine you'll find others with the same issue. Version 45 will help but you must load the latest version of Flash or FF will block it. There are ways around this but I'm not ready to go there on this forum.

Regards,
GEWB

 

[Callender]

C:\Documents and Settings\User\Desktop\autodetectutility.exe is not a valid Win32 application

I think that you get that sort of error when there's a problem with MS Visual C++ (version or security update missing) or corrupt version that needs removal and then reinstalling.

​

Are you using an Administrator account (I mean, any account that is an administrator, not the admin account itself)? Looks like a Basic account limitation...

To help out FerchogtX run netplwiz and post a screenshot of the results.

​

 

[randomwin7user]

 

[Callender]

Thanks for the screenshot.

I can replicate the problem using Cyberfox (Firefox 64bit variant).

1) Tested Twitter video playback in Cyberfox and it worked fine.

2) Modified preference media.windows-media-foundation.enabled
and set it's value to false

3) Restarted Cyberfox (Firefox) and get the following error:

​

If I undo the change then Twitter videos will play.

So to test - launch firefox and in the address bar type:

about:config

Accept the warning. In the search box type:

media.windows-media-foundation.enabled

Set it's value to true by double clicking.

​

Exit Firefox and launch it again. Try playing a Twitter video.

Of course this will not help if that preference is already set to true

 

[Callender]

In addition you might want to check that the following preference is also set to true

media.mediasource.enabled
​

​

 

[FerchogtX]

Solutions

I'm impressed you find out the problem, the trobleshoot page didn't exhibit this particular issue... I wonder why since it's supposed this settings are set to true by default, and if set to false, it's non defaut, thus has to be shown on about:support... (that just means I'm so dumb XD)

Anyway, I'm certain this will fix his problems with video playback. Thanks for this

 

[Callender]

I wonder why since it's supposed this settings are set to true by default, and if set to false, it's non defaut, thus has to be shown on about:support.

It should show up in profile info (about:support) and looking at the list of modified preferences that were already posted - it doesn't show up so I guess that it's not the problem!

Anyway if it's any help Twitter video works for me and here's my list:

Application Basics
------------------

Name: Cyberfox
Version: 45.0.2
Build ID: 20160316131255
User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:45.0) Gecko/20100101 Firefox/45.0 Cyberfox/45.0.2
Multiprocess Windows: 0/1 (default: false)
Safe Mode: false

Extensions
----------

Name: CanvasBlocker
Version: 0.3.0-Release
Enabled: true
ID: [email protected]

Name: Certificate Patrol
Version: 2.0.14.1-signed
Enabled: true
ID: [email protected]

Name: Click to Play per-element
Version: 0.3.3
Enabled: true
ID: [email protected]

Name: Click&Clean
Version: 4.1.1-signed
Enabled: true
ID: [email protected]

Name: CyberCTR
Version: 1.5.1
Enabled: true
ID: [email protected]

Name: Disconnect
Version: 3.15.3.1-signed
Enabled: true
ID: [email protected]

Name: eCleaner
Version: 1.4.1-signed.1-let-fixed
Enabled: true
ID: {c72c0c73-4eb0-4fb3-af0f-074e97326cfd}

Name: Empty Cache Button
Version: 2.7.1-signed
Enabled: true
ID: {4cc4a13b-94a6-7568-370d-5f9de54a9c7f}

Name: Extension Defender
Version: 1.0.3.1-signed
Enabled: true
ID: {281944CE-E7F4-4A43-A5D0-EAC0B3E71BFF}

Name: Foundstone HTML5 Local Storage Explorer
Version: 1.1.1-signed
Enabled: true
ID: [email protected]

Name: friGate - unlock sites
Version: 2.2.1
Enabled: true
ID: [email protected]

Name: HTTPS-Everywhere
Version: 5.1.4
Enabled: true
ID: [email protected]

Name: Metascan Online Firefox Plugin
Version: 0.2
Enabled: true
ID: [email protected]

Name: Preferences Monitor
Version: 3.6.1.1-signed.1-let-fixed
Enabled: true
ID: {517f9e52-c795-4764-bf77-5e2db596cee6}

Name: Redirect Cleaner
Version: 2.4.0
Enabled: true
ID: [email protected]

Name: Resurrect Pages
Version: 3
Enabled: true
ID: {0c8fbd76-bdeb-4c52-9b24-d587ce7b9dc3}

Name: Secret Agent
Version: 1.32
Enabled: true
ID: [email protected]

Name: Self-Destructing Cookies
Version: 0.4.9
Enabled: true
ID: jid0-9XfBwUWnvPx4wWsfBWMCm4Jj69E@jetpack

Name: SSleuth
Version: 0.4.5
Enabled: true
ID: ssleuth@github

Name: Toggle JavaScript
Version: 0.8
Enabled: true
ID: jid1-KYgT07tufVQH4w@jetpack

Name: TrafficLight
Version: 0.2.23.1-signed
Enabled: true
ID: [email protected]

Name: WOT
Version: 20151208
Enabled: true
ID: {a0d7ccb3-214d-498b-b4aa-0e8fda9a7bf7}

Name: Calomel SSL Validation
Version: 0.79
Enabled: false
ID: [email protected]

Name: Lightbeam
Version: 1.3.0.1-signed
Enabled: false
ID: jid1-F9UJ2thwoAm5gQ@jetpack

Name: Nimbus Screen Capture - editable screenshots.
Version: 8.2.1
Enabled: false
ID: [email protected]

Name: uMatrix
Version: 0.9.3.3
Enabled: false
ID: [email protected]

Graphics
--------

Adapter Description: AMD Radeon HD 6290 Graphics
Adapter Drivers: aticfx64 aticfx64 aticfx64 aticfx32 aticfx32 aticfx32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64
Adapter RAM: 384
Asynchronous Pan/Zoom: none
ClearType Parameters: Gamma: 2200 Pixel Structure: R ClearType Level: 100 Enhanced Contrast: 300
Device ID: 0x9807
Direct2D Enabled: Blocked for your graphics card because of unresolved driver issues.
DirectWrite Enabled: false (6.2.9200.17568)
Driver Date: 12-6-2013
Driver Version: 13.251.0.0
GPU #2 Active: false
GPU Accelerated Windows: 1/1 Direct3D 11 (OMTC)
Subsys ID: 14b71043
Supports Hardware H264 Decoding: Yes
Vendor ID: 0x1002
windowLayerManagerRemote: true
AzureCanvasBackend: skia
AzureContentBackend: cairo
AzureFallbackCanvasBackend: cairo
AzureSkiaAccelerated: 0

Important Modified Preferences
------------------------------

accessibility.typeaheadfind.flashBar: 0
browser.cache.disk.capacity: 0
browser.cache.disk.enable: false
browser.cache.disk.filesystem_reported: 1
browser.cache.disk.smart_size.enabled: false
browser.cache.disk.smart_size.first_run: false
browser.cache.disk.smart_size.use_old_max: false
browser.cache.frecency_experiment: 4
browser.cache.memory.capacity: -1
browser.download.folderList: 2
browser.download.importedFromSqlite: true
browser.places.smartBookmarksVersion: 7
browser.sessionstore.upgradeBackup.latestBuildID: 20151015111139
browser.startup.homepage: https://encrypted.google.com
browser.startup.homepage_override.buildID: 20151015111139
browser.startup.homepage_override.mstone: ignore
browser.urlbar.autocomplete.enabled: false
browser.urlbar.suggest.bookmark: false
browser.urlbar.suggest.history: false
browser.urlbar.suggest.openpage: false
dom.apps.reset-permissions: true
dom.ipc.plugins.flash.subprocess.crashreporter.enabled: false
dom.ipc.plugins.reportCrashURL: false
dom.min_background_timeout_value: 100000
dom.mozApps.used: true
extensions.lastAppVersion: 45.0.2
font.default.x-western: sans-serif
font.internaluseonly.changed: true
font.name.serif.x-western: Arial
general.autoScroll: false
gfx.blacklist.direct2d: 4
gfx.blacklist.layers.direct3d9: 4
gfx.crash-guard.d3d11layers.appVersion: 45.0.2
gfx.crash-guard.d3d11layers.deviceID: 0x9807
gfx.crash-guard.d3d11layers.driverVersion: 13.251.0.0
gfx.crash-guard.d3d11layers.feature-d2d: false
gfx.crash-guard.d3d11layers.feature-d3d11: true
gfx.crash-guard.status.d3d11layers: 2
gfx.crash-guard.status.d3d9video: 2
gfx.direct3d.last_used_feature_level_idx: 0
gfx.driver-init.appVersion: 41.0.3
gfx.driver-init.deviceID: 0x9807
gfx.driver-init.driverVersion: 13.251.0.0
gfx.driver-init.feature-d2d: false
gfx.driver-init.feature-d3d11: true
gfx.driver-init.status: 2
media.gmp-gmpopenh264.lastUpdate: 1454471380
media.gmp-gmpopenh264.version: 1.5.3
media.gmp-manager.buildID: 20160316131255
media.gmp-manager.lastCheck: 1458461303
media.hardware-video-decoding.failed: false
network.allow-experiments: false
network.cookie.cookieBehavior: 1
network.cookie.lifetimePolicy: 2
network.cookie.prefsMigrated: true
network.http.sendRefererHeader: 0
network.predictor.cleaned-up: true
places.database.lastMaintenance: 1439154381
places.history.enabled: false
places.history.expiration.transient_current_max_pages: 96852
plugin.disable_full_page_plugin_for_types: application/pdf
plugin.importedState: true
plugin.state.flash: 1
privacy.cpd.extensions-certpatrol: false
privacy.cpd.offlineApps: true
privacy.cpd.siteSettings: true
privacy.donottrackheader.enabled: true
privacy.donottrackheader.value: 1
privacy.sanitize.migrateFx3Prefs: true
privacy.sanitize.sanitizeOnShutdown: true
privacy.sanitize.timeSpan: 0
security.disable_button.openCertManager: false
security.disable_button.openDeviceManager: false
security.ssl.treat_unsafe_negotiation_as_broken: true
security.ssl3.dhe_dss_aes_256_sha: true
security.ssl3.dhe_rsa_des_ede3_sha: true
security.ssl3.ecdhe_ecdsa_rc4_128_sha: false
security.ssl3.ecdhe_rsa_des_ede3_sha: true
security.ssl3.ecdhe_rsa_rc4_128_sha: false
security.ssl3.rsa_rc4_128_md5: false
security.ssl3.rsa_rc4_128_sha: false
security.tls.insecure_fallback_hosts.use_static_list: false
security.tls.unrestricted_rc4_fallback: false
services.sync.declinedEngines:
storage.vacuum.last.index: 1
storage.vacuum.last.places.sqlite: 1439154381
webgl.disabled: true

user.js Preferences
-------------------

Your profile folder contains a user.js file, which includes preferences that were not created by Cyberfox.

Important Locked Preferences
----------------------------

JavaScript
----------

Incremental GC: true

Accessibility
-------------

Activated: false
Prevent Accessibility: 0

Library Versions
----------------

NSPR
Expected minimum version: 4.12
Version in use: 4.12

NSS
Expected minimum version: 3.21.1 Basic ECC
Version in use: 3.21.1 Basic ECC

NSSSMIME
Expected minimum version: 3.21.1 Basic ECC
Version in use: 3.21.1 Basic ECC

NSSSSL
Expected minimum version: 3.21.1 Basic ECC
Version in use: 3.21.1 Basic ECC

NSSUTIL
Expected minimum version: 3.21.1
Version in use: 3.21.1

Experimental Features
---------------------

 

[GEWB]

I'm glad Callender and I were able to help! Be sure to mark the thread as SOLVED if it is indeed fixed (to help others searching the forum).

Regards,
GEWB

 

[Callender]

@ randomwin7user

Did you delete your last post?

Anyway you seem to have stated that those preferences do not exist. They should.

Suggestion:

Backup bookmarks, extensions and additionally make a backup copy of your Firefox Profile and profile.in file but keep them stored away from your AppData directory.

Fully remove Firefox (add/ remove programs will not fully remove it) and reboot. Install a fresh copy and restore your bookmarks and extensions then test.

Another test you can do:

To rule out any problem with codecs or missing windows updates download a copy of Cyberfox Portable. It uses it's own separate profile and doesn't share it with Firfox unlike some other firefox variants.

See if you can play twitter videos with that.

Cyberfox 64bit Intel Optimized version (no java plugin)

https://cyberfox.8pecxstudios.com/cyberfox-intel-version-x64/

Cyberfox 32bit Intel Optimized version:

https://cyberfox.8pecxstudios.com/cyberfox-intel-version-x86/

Take your pick and download the Portable Zipped Archive. Extract the files and run the browser. Test twitter video. Also check the preferences mentioned earlier.

RE: Firefox.

It can screw up sometimes if you just keep applying available updates instead of clean installing it from time to time especially after the release of a version that has major upgrades.