Napisa ove upute na stackowerflow, pa vam mogu i tu pejstati za operu.
install the chromium codecs from snap by:
sudo snap install chromium-ffmpeg
Then go to the created /snap/chromium-ffmpeg directory and search for the libffmpeg.so file (I just selected the folder with the higher number supposing is the newest, in my case /snap/chromium-ffmpeg/15/chromium-ffmpeg-95241).
Copy and replace the libffmpeg.so file to the /usr/lib/x86_64-linux-gnu/opera directory. That worked for me.