I believe your solution lies in manually installing "restricted formats". Ironically this, or something that sounds like it can be found in the software center, but trial and error has taught me that despite the claims it is not the same. You must add this in the terminal exactly as it is describe on THIS LINKED PAGE.
As my other answers and comments attest, I am not a big fan of the Terminal/CLI. I accept there are times it is necessary. This is such an occasion.
Alternatively you can visit the Apps page of restricted extras in stock Ubuntu (ubuntu-restricted-extras ) and click on the big orange graphic reading "available on the Software Center".
EDIT BY ORIGINAL AUTHOR: The inserted edit directly above is faulty! Its fallacy is reference within my post, proving he failed to read my post before editing it!