Video and sound under Ubuntu:(!

Some video formats, such as Flash, QuickTime, and Windows Media Video, are proprietary and so support for them cannot be included in Ubuntu by default. You must install some extra software to allow playback.

In order to play the most common proprietary formats in the Totem movie player or Firefox web browser, install the ubuntu-restricted-extras package (see Restricted Software for more information).

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https://help.ubuntu.com/10.10/add-applications/C/#restricted-software

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Software is available from third-party sources, as well as from the default Ubuntu software repositories. If you want to install software from a third-party software repository, you must add it to the package manager's list of available repositories.
[Caution]

Only add software repositories from sources that you trust. Third-party software repositories are not checked for security by Ubuntu members, and may contain software which is harmful to your computer.

1. Open System → Administration → Software Sources and select Other Software.

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Click Add to add a new repository.
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Enter the APT line for the extra repository. This should be available from the website of the repository, and should look similar to the following:

deb http://archive.ubuntu.com/ubuntu/ maverick main

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