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Cannot play media. No decoders for requested formats: video/mp4

  • 3 replies
  • 1 has this problem
  • 84 views
  • Last reply by FredMcD

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Suddenly, most videos won't play. Upon closer inspection of the console messages, I get the following: "Cannot play media. No decoders for requested formats: video/mp4; codecs="avc1.42E01E mp4a.40.2", video/mp4; codecs="avc1.42E01E mp4a.40.2", video/mp4; codecs="avc1.42E01E mp4a.40.2", application/x-mpegurl, video/mp4; codecs="avc1.42E01E mp4a.40.2", application/x-mpegurl"

Only on Firefox, I can play mp4 videos normally in other browsers and media players. Tried reinstalling Firefox, refreshing, restarting the browser and the computer... My about:config media.mp4.enabled is set as "TRUE".

Other messages from the console:

"[warn][id_playback] id playback error: Object { code: "DNS", description: "Device not supported", reportAs: "INFO", internalError: true } player.min.js:1:55026 [error][player_error] <empty string> Object { description: "Device not supported""

Also tried disabling hardware acceleration and restarting the browser.

I'm clueless!

All Replies (3)

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Tried everything as instructed on these pages, no change...

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If you have Windows 10 N or KN then you may not have the Media Feature Pack installed. https://support.mozilla.org/en-US/kb/fix-video-audio-problems-firefox-windows