From LinuxMCE wiki
This page defines what a Media Director (MD) is, what it does, how it fits in the LinuxMCE system, and how to select the components necessary for an enjoyable media experience.
What is a Media Director?
A Media Director (also known as a Media Station) is a PC which channels the audio and video content managed by the LinuxMCE system to the audiovisual devices which are connected to it. Media Directors (MDs for short) are Home Theater PCs (HTPC) with outputs to connect to a television and to speakers. A MD can play all your streaming music and videos, whether from the Core, from network attached storage (NAS), or from other MDs in your system.
Media Directors and the LinuxMCE system
A LinuxMCE system is made of a single Core and multiple Media Directors. While it is possible to run the Core as a Media Director also, making it a hybrid Core/Media Director, you still need a dedicated Media Director for each room or entertainment area where you would like to receive the media. With multiple rooms, this results in multiple Media Directors present in the LinuxMCE system.
Each Media Director is connected to the LinuxMCE Core server through the home automation/multimedia LAN by its LAN port (NIC). It is also fitted with connections for the TV, stereo or other AV devices through which content is output to the AV devices connected to it. A Media Director PC needs LAN and A/V ports (such as VGA, HDMI, S-video or RCA jacks), and is generally located close to the viewing/listening area.
Media Director PC components
A Media Director is selected based on the quality of the images and sound it can produce, and the connections necessary for the A/V application. Choosing or building a PC that will be used as a Media Director must be done carefully with respect to the input and output capabilities of that PC. These demands are more easily met with a Media Director than with a Home Theater PC, since many of the functions of a standalone HTPC have been moved to the Core in a LinuxMCE system, reducing the hardware requirements of each Media Director, making the Media Director much less expensive than a Home Theater PC.
This section explains the role of each component, and gives you the understanding you need to select Media Directors.
Audio and video
Because media is served through the graphics and sound cards of the Media Director PC, it needs to have a good (nVidia) graphics card and a good sound card (e.g. with 5.1 or 7.1 outputs). Outputs to TV and stereo are directly from a Media Director, so quality output cards are needed.
The Core generally has the TV tuner card for the entire system. A Media Director does not typically need one.
A Media Director also provides the interface for input devices. Remote controls (USB-UIRTs, bluetooth devices, etc), in general, are connected to a Media Director.
While a dedicated core can be hidden in a closet or somewhere else, each Media Director is generally attached to a TV or entertainment center. As such, it has requirements similar to a Home Theater PC: it should be whisper-quiet (either with very quiet fans or a fan-less heat sink), have low heat emission (which usually implies low power consumption) and be small and unobtrusive (in a stylish case).
Unlike a Home Theater PC, the Media Director does not require a large storage capacity. Storage functions are provided by the Core (or hybrid), not the Media Director. You can, however, add storage to a Media Director, but it is not necessary since the Core carries the PVR and all network media storage functions for the entire system. Only the Core needs a large hard drive storage capacity.
It is important to note that video decoding takes place locally on the Media Director. It would be prudent to ensure that the processing power of the Media Director is sufficient for your media, be it standard definition or high definition content.
Media Director OS
A Media Directors does not require an OS. It can act as a thin client, netboot from the Core, and be fully operational within minutes.
When a Core is also used as a Media Director, it is called a Hybrid. Since a Hybrid Computer performs all the Core functions and the Media Director functions also, it needs to be capable and all the recommendations for Media Directors apply.