How to Solve “Opera browser cannot play web video” Issue

Solution:

Replace Opera’s libffmpeg.so

sudo cp /usr/lib/chromium-browser/libffmpeg.so /usr/lib/x86_64-linux-gnu/opera/libffmpeg.so

Or because of the lack of chromium-codecs-ffmpeg-extra, you need to install it manually

sudo apt install chromium-codecs-ffmpeg-extra