You don't need to install Chrome or Chromium, just the proper libs. On linux mint 17.2 with Opera 32.0.1948.69, do the following.

Open a terminal (ctrl-alt-t)

Enter the following commands:

sudo apt-get install chromium-codecs-ffmpeg-extra 
sudo mkdir /usr/lib/x86_64-linux-gnu/opera/lib_extra/
sudo ln -s /usr/lib/chromium-browser/libs/libffmpeg.so /usr/lib/x86_64-linux-gnu/opera/lib_extra/libffmpeg.so.32

Restart opera