Hardware Reference
In-Depth Information
And, finally, the total size of the distribution needs to be determined. This is always the last consideration
because it can be solved with very little effort, namely, with an extra few cents on a larger hard drive or solid-state
memory card. The latter is preferable for most media streamer machines as you can boot quicker from them, they
last longer (since more of the operations are memory reads, not memory writes, and have no moving parts), and they
allow for a much smaller form factor. If you are building your own Linux machine specifically for media streaming,
then make sure that it can support booting from compact flash or a USB memory stick.
The Software
A good media player distribution depends not primarily on the operating system but on the software. It is, after all, the
software with which you will be interacting. Most media streamers start life as media players. These are completely
wrong for a streamer. Consider the basic scenario—you have a media player on your desktop controlled by a mouse
and keyboard while sitting on a chair and watching a monitor that is 2 to 3 feet away. Alas, most software is developed
and tested on a desktop PC, where the subtle differences might be overlooked. Remember to consider the following:
The visuals
: You will be generally using the interface from a long distance away in a comfy
chair. Therefore, the buttons and font need to be large and legible, placed on a screen that
is uncluttered and moderately high contrast, with antialiasing.
The screen
: Unless you have the latest LCD technology in your living room, your TV will
generally be of a much lower quality than your monitor, so small details (especially thin
horizontal lines) will get lost or be indistinguishable on-screen.
Control
: Without exception, any home theater PC without a remote-control option is going
to fail. No one will get out of that comfy chair to press buttons on the machine or will want a
keyboard or mouse on their lap.
Navigable interface
: Going hand in hand with control, there must be a clean way of moving
between menu options. Entering the server IP with a keyboard is only acceptable during
initialization.
All of these points have been classified together as an approach known as the “10-foot user interface.” This is not
to say that these rules are golden or immutable, but spotting several contraventions to this in a single piece of software
can be a clue that the project is not yet particularly mature and has been used little in the real world.
MythTV
Of all the Linux PVRs out there, the most famous is probably MythTV (
http://www.mythtv.org
). This consists of two
parts—a back end (
mythback
) that allows you to record shows from a TV card into the local hard disk and a front end
that plays back the media files from a
mythback
server. In this way, you can have a powerful single server containing
many TV cards with the software coordinating the best way to record channels with them and a number of smaller
front end units placed in the various rooms of the house all taking their data from the server. This also provides a way
of streaming live TV around the house.
In addition to media playback, MythTV supports alternative skins and plug-in modules, allowing the front-end
units to display the weather, show a photo gallery, play games, and surf the Web.
If you are looking for a PVR stand-alone form-factor, you can incorporate both
mythback
and
mythfront
into
the same machine, provided that it is powerful enough. A TV card with hardware encoding (such as the newer
Hauppauges) can help reduce the size and power of this machine, allowing you to get away with a fanless system.
The software approach to PVRs will always win out over hardware, because new features can be added more
efficiently and vagaries in codecs can be catered for. I'll now briefly cover some examples.
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