Hi, are there separate drivers for your sound or a special card you are running ? VIDEO AUDIO *https://support.google.com/youtube/topic/3014746 *https://support.mozilla.org/en-US/kb/fix-common-audio-and-video-issues *https://support.mozilla.org/en-US/kb/html5-audio-and-video-firefox *https://support.mozilla.org/en-US/kb/fix-video-audio-problems-firefox-windows

   Troubleshoot video streaming issues    
     If you have many browser tabs open, try to close most of them except the one you’re using for YouTube.

     Restart your browser.

     Restart your router.

     Restart your computer.

     Update your browser to the latest version.

     Use Chrome.

   Troubleshoot YouTube error messages

   Video not available in my country

   Google Video Quality Report

   Can’t see private videos

   YouTube videos missing quality options on this browser

   Volume button is disabled on YouTube

   Clear cache & cookies

   Wrong video title, description, or thumbnail on Facebook

   Send YouTube debug information

   Install missing plugins

   Enable or activate plugins

   Update your plugins

   Allow Plugin Container in your Internet security program

   Clear the cache

   Disable interfering extensions or ad-blocking software

   Check some Firefox settings

   Remove specific entries in the hosts file (advanced users)

https://support.google.com/youtube/topic/3014746 Troubleshoot video streaming issues If you have many browser tabs open, try to close most of them except the one you’re using for YouTube. A: No other tabs open Restart your browser. A: No effect Restart your router. A: No effect Restart your computer. A: No effect Update your browser to the latest version. A: No newer versions available Use Chrome. A: Everything works fine in Chrome Troubleshoot YouTube error messages A: No problems watching youtube videos Video not available in my country A: Not applicable; only youtube videos play Google Video Quality Report A: Not applicable; the same non-playing videos work in chrome Can’t see private videos A: Not applicable; not even video ads will pay YouTube videos missing quality options on this browser A: Not applicable; there seem to be no problems with YouTube videos Volume button is disabled on YouTube A: See above Clear cache & cookies A: No Impact Wrong video title, description, or thumbnail on Facebook A: Not applicable; same videos play in chrome Send YouTube debug information A: Not applicable, youtube videos play https://support.mozilla.org/en-US/kb/fix-common-audio-and-video-issues You may need to install the required PulseAudio software A: PulseAudio re-installed; no effect HTML5 audio and video Plugins Install missing plugins A: Plugins are not missing and reinstall has to effect Enable or activate plugins A: Plugins are active and disactiving and reactivating has no effect Update your plugins A: There are no newer updates Allow Plugin Container in your Internet security program A: Not applicable; no containers in use Other solutions Clear the cache A: No effect Disable interfering extensions or ad-blocking software A: Adblocking software not installed; no extensions installed Check some Firefox settings A: Permissions enabled; no effect Remove specific entries in the hosts file (advanced users) A: Not applicable https://support.mozilla.org/en-US/kb/html5-audio-and-video-firefox A: Irrelevant; I can see the audio and video controls but clicking and keyboard controls will not start video playback https://support.mozilla.org/en-US/kb/fix-video-audio-problems-firefox-windows A: Ignored; this is on Linux, not windows

Did you check the Web Console for error messages? *https://developer.mozilla.org/en/Tools/Web_Console Do you have the latest FFmpeg packages installed?