Most web videos play fine for me in Firefox. Occasionally on Twitter I'll come across a video that plays with the audio track at very slow speeds like this one: https://twitter.com/ForTheRuleOfLaw/...49832424202241
I've gone through the obvious suggestions at Firefox Support. I've cleared the cache and disabled uBlock Origin and Ghostery all to no avail. A Google search doesn't bring up other postings about this issue.
I installed google-chrome-stable from the Google repository; it does not have this problem. Neither does chromium.
I'm using Firefox 68.0.1 on Kubuntu 19.04.
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