The general answer to questions about missing video codecs is to install ubuntu-restricted-extras. But that metapackage also includes the ttf-mscorefonts-installer which requires acceptance of a EULA to finish. Not everyone wants to sign the EULA, but there's no obvious way to reject the EULA. See How to reject an EULA when installing packages with apt?
I wound up going back and forth a few times before I seemed to move on -- I think clicking Fwd, Fwd without ever accepting the EULA works, but the package is installed now, so the installation of this package was not canceled.
Does that mean I did accept the EULA? Is there somewhere I can look to see whether or not that acceptance was logged or stored?
dpkg-query clearly shows the package as installed:
amanda@mona:~$ dpkg-query -l ttf-mscorefonts-installer Desired=Unknown/Install/Remove/Purge/Hold | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad) ||/ Name Version Architecture Description +++-==============-============-============-================================= ii ttf-mscorefont 3.4+nmu1ubun all Installer for Microsoft TrueType