I know this doesn't help for 'in browser' playback, but this works on 10.5.8 Leopard and PPC Linux on my machines:
Code:
youtube-dl -f 360p -o - https://twitch.tv/channel-name | ffplay -
(or you can use mpv, vlc, etc (except mplayer) if you don't like ffplay) CPU use on a 1.67ghz Powerbook G4 averages 40-60% live streaming in 360p. Then connect your irc client to twitch to join the conversation. I haven't tried this on MorphOS yet though.
twitch-chat-ppc-linux2-png.878759screenshot-480p-g4-png.880000[ Edited by wicknix 08.10.2021 - 23:15 ]