VLC

VLC media player is a wildly popular, cross platform video player and streamer. VLC media player has been quickly achieving its goal of world domination since its initial release in February of 2001.

USE flags
According to VideoLAN some certain USE flags need to be set in order to not get a very bare bones version of VLC. Many of them might be obsolete or be set by the selected profile. For the standard desktop profile one might add to like

Streaming online multimedia
VLC provides users with the option to stream multimedia objects (YouTube, Vimeo, music, and more) to enable this functionality simply enable the  USE flag, if you have  installed, it is a highly recommended package to have, simply issue:

After proper configuration and installation to stream multimedia in VLC you will find the option under in it you will be able to input URLs to popular multimedia websites such as YouTube along with other websites as well.

Support For Webm
Webm is a popular video format, to have it work you must enable vorbis, vpx and matroska

Emerge
After setting desired USE flags for the initial installation, emerge VLC:

Configuration
VLC is an extremely powerful program capable of playing almost any media file. It can even "play" binary files, although it is really not worth trying since there is really no point in "playing" most binaries.

Alternate interfaces
VLC provides multiple interfaces in addition to the default GUI interface. There is an ncurses-based interface, and a HTTP interface that can be used for streaming or as a remote control. The VLC wiki has a section dedicated to explaining the alternative interfaces.

Users may become confused when using VLC via Portage because, by default, the ebuild does not include the USE flags needed in order to include the dependencies needed for the alternative interfaces. Search the USE flag section above for interface related flags.

Once the flags have been set recompile VLC by using the following command:

HTTP
When connecting to the HTTP interface, make sure a password is set.

Leave the user name field blank when entering credentials on the web page leave the user name blank.

Hotkeys
VLC supports a host of hotkeys for more efficient operation. There is an article on the VLC wiki detailing all available hotkeys for the Qt interface.

External resources

 * http://www.hongkiat.com/blog/vlc-tips-tricks/ - Tips and tricks for VLC.
 * http://lifehacker.com/the-best-hidden-features-of-vlc-1654434241 - A lifehacker article on hidden features in VLC.
 * http://www.shortcutworld.com/en/win/vlc-media-player.html - A list of keyboard shortcuts for VLC. Highly useful if VLC is frequently used!