Currently included Firefox in Fedora 34 ( firefox-87.0-7.fc34 ) doesn't allow to play Widevine VP9 videos out of the box . This is fixed in firefox-87.0-12.fc34.
Proposed as a Freeze Exception for 34-final by Fedora user frantisekz using the blocker tracking app because: This can be fixed by an update, but there is no harm in having it fixed on GA, so users desperately trying to play Netflix before updating the OS won't hit this.
Discussed during the 2021-04-19 blocker review meeting: [0] The decision to classify this bug as an "AcceptedFreezeException (Final)" was made as it is a noticeable issue that cannot be fixed with an update. [0] https://meetbot.fedoraproject.org/fedora-blocker-review/2021-04-19/f34-blocker-review.2021-04-19-16.00.txt
FEDORA-2021-b20dce00b2 has been submitted as an update to Fedora 34. https://bodhi.fedoraproject.org/updates/FEDORA-2021-b20dce00b2
FEDORA-2021-b20dce00b2 has been pushed to the Fedora 34 stable repository. If problem still persists, please make note of it in this bug report.