YouTube now defaults to AV1. The extension was last updated 6 years ago, so it still only blocks VP8/VP9.

EDIT: After changing this setting to false in about:config it works: media.av1.enabled

Melhorou a reprodução de vídeo do YouTube no meu notebook antigo. Agradeço aos desenvolvedores.

not sure when "no longer" remark appeared, but accidentally finding out it hides 2/4K quality makes it not worth for me anymore.

Kills that pesky AV1 but it's a shame VP9 was caught in the crossfire as YouTube preforms much worse trying to broadcast VP9 as H.264. Just use Enhanced h264ify.

YouTube now defaults to AV1. The extension was last updated 6 years ago, so it still only blocks VP8/VP9.

EDIT: After changing this setting to false in about:config it works: media.av1.enabled

Jeżeli nie oglądasz w rozdzielczości wyżej niż 1080p to polecam zainstalować bo po pierwsze możliwy płynniejszy film, po drugie mniejsze zużycie prądu ponieważ stój sprzęt potrzebuje mniej prądu, a po trzecie jeżeli chcesz to możesz zajrzeć w kod tego rozszerzenie, czyli możesz zweryfikować że nie zbiera żadnych danych

Fixed my lag

Perfect. Got an i5 6300hq, was having ~50% CPU usage while watching 1080p@60fps. With this i got 25-30% CPU usage. Thank you!

Not working anymore - I still have av1.

A must have for old laptops with no VP9 hardware decoding support. Just make sure that you can only watch videos up to 1080p.