I have found an answer to this finally.
here is how it is done
Make sure that you have gecko-sdk 1.6 newer versions will not work properly with Opera
Download the source code then do these following commands in the source code directory:
./configure --enable-x [--with-gecko-sdk={path} ]
make
cp mplayerplug-in.so /usr/lib/opera/plugins
ln -s /usr/lib/mozilla/libxpcom.so /usr/lib
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