# Introduction

## What does it do?

Universal Media Server (or UMS for short) is a program that streams media like video, audio or images from your computer or the web to a device like a console or a TV.

This might sound simple, but it is in fact a complex matter. There are dozens of media formats in the world, and your console or TV only understands a couple of them. UMS allows you to browse media on your favorite viewing device without having to worry about the details of what you are viewing. UMS takes care of retrieving the media (from file, network or web) and translating it to the best format that your device understands.

## Media renderers

UMS is a DLNA compliant UPnP Media Server. It was originally written to support the PlayStation 3. However, other viewing devices support the same standards as the PlayStation 3 and UMS has been expanded to support a range of them, including Xbox 360 and various Samsung and Sony televisions.

## Alternatives

There are several streaming servers available which can be used to communicate with a your viewing device. Here is a small selection:

- Windows Media Player
- Twonky Media
- TVersity
- MediaTomb

Windows Media Player works well out of the box but isn't able to transcode or remux and has poor performance with a huge media database. Twonky media is not for free. Twonky media has its advantages in supporting a lot of different streaming clients, even NAS systems. TVersity is an average media server and has some advantages in streaming Internet content. But this advanced feature is not included in the free version. Mediatomb is often used on open source operating and embedded systems. It can be customized very well by experienced shellscript gurus. It is not a good choice for beginners.

## Why UMS?

UMS is available for Windows, Linux and Mac OS X. A prerequisite is the installation of Java Runtime Environment (JRE) because UMS is programmed in Java.

UMS is shipped with all required software to make it work out of the box. However, additional features may require the installation of additional software.

There are a lot of technical details involved in the process of translating media. UMS tries to minimalize this for the user by shipping with working defaults for most situations. You simply start UMS and it will find your device and start communicating with it without any extra configuration.

UMS is optimized for use with the Playstation 3. But you can also use an Xbox 360, Popcorn Hour and various Samsung or Sony TVs as streaming clients.

In the old days, people would use a conversion program like "mkv2vob" and connect USB hard drives with converted files to the PS3. With UMS there is no need for converting files any more. If converting is necessary, UMS will do it for you on the fly.

UMS also makes it possible to stream web content like Youtube, GameTrailers, web radio or Picasa to your device.

UMS is free Open Source software and has been designed to allow third party plugins to extend its functionality. You are welcome to help improve UMS or write a plugin for others to use. See the project homepage for more information.

The most stunning features of UMS are transcoding and muxing.

## What are transcoding and muxing?

If the video codec is not supported UMS can convert the video stream to a device compatible codec. For example the PS3 is compatible with MPEG2. This procedure is called transcoding and it costs a lot of CPU power.

When you try to play a media file on your viewing device and the format is not supported you get a "data corrupted" message. UMS is able to help in this case. UMS is able to change the container format on the fly if it is not supported by your device. UMS extracts the audio and video stream and puts it into a supported M2TS-container. This is called muxing.

Together, transcoding and muxing make it possible for UMS to stream almost every multimedia format to your viewing device. UMS enables you to view media on TV that you could formerly only view on your computer.

## Hardware requirements

You can stream media files with quite old computers. If the device does not recognize the video container format and UMS has to remux you will need some additional CPU power. A 2 GHz CPU should be sufficient. When transcoding a video on full HD resolution an up to date dual core processor from Intel or AMD with at least 2,6 GHz is necessary.

It is also necessary to have enough network bandwidth available when streaming HD videos. It is nearly impossible to stream a full HD video via WLAN, even when restricting network bandwidth and setting video quality very low.

You should also have enough free RAM, which means about 512 MB. There is also some space needed on your systems hard drive for buffering videos. 500 MB free disk space is enough. If you want to stream media files from an external hard drive please consider that an USB 1.1 connection is too slow for videos.

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