A Beginning Look At MythTV

MythTV is a software package that lets you turn
your Linux-based computer into a television and personal video
recorder (PVR) by recording shows onto the hard disk. MythTV
lets you select the TV shows you want to record by using
an on-screen menu, pointing and clicking your way way through
a schedule by show name or time.

MythTV is similar to TiVo in its ability to record TV shows onto a hard
drive. MythTV also offers a point-and-click scheduling feature with TV listings
downloaded off the Internet, the same way that TiVo does. Unlike a TiVo,
however, you can build as much storage into a MythTV box as the
Linux kernel and/or your budget allows. With its links to Xmame,
MythTV also lets your box act as a video arcade. Similar to the X Window
System, MythTV is set up on a client/server model. This means the TV
tuner card(s) can be in one computer while the display is in another
computer(s).

The ability to watch TV shows over the network can be
a great thing. For example, I once worked in the
consulting arm of a Canadian accounting firm. Every
time a new Federal budget was introduced into
Parliament, the entire accounting staff was required to watch TV at the
office so we could follow along. At home, too, it can be nice
to have only a laptop with a wireless connection to
your server and still be able to watch TV. With MythTV,
one server box can provide TV for a number of Linux
desktops, be it in a home or office setting.

When considering whether to use MythTV, the first question to ask is, "Does MythTV make sense
from a cost standpoint?" A used TiVo PVR often can be
found in on-line auctions such as e-Bay for under $100, and TiVo offers
many--but not all--of the features MythTV has. So, if you can do
this MythTV project for under $100, or if you
really want features that MythTV has and TiVo doesn't,
then great, go with MythTV. Otherwise, it may be wiser to
look at a TiVo or one of TiVo's direct competitors.

The other consideration to make is how much free time do
you want to commit to this project? MythTV is not an easy
program to get installed and running. I have run into
issues with drivers for different TV capture cards
conflicting, database security and several other problems. All of
these issues are solvable, but they all take time to deal with--in some
cases, significant amounts of time.

If you decide to proceed with MythTV, the next question is, "What
hardware do I need?" Running MythTV will test your hardware in a number of
ways, so you need to pay attention to everything from
video cards to hard drives to cases. When it comes to
disk storage, you are looking at upwards of 2GB per hour of recorded
programming. Even more space is required if you're dealing with HDTV, so if you have less than
40GB of free space, you likely should be checking
prices of new hard drives. If you do get a new hard
drive for MythTV, keep filesystems in mind. MythTV is storage hungry and expects all program files
to be in the same directory. Logical Volume Management,
which allows you to add drive space as needed, is
worth careful consideration here.

For TV tuner cards, the gold standard is the Hauppauge PVR cards,
as they all can do MPEG-2 encoding on the card without depending on the
main CPU. As of this writing, the Hauppauge PVR
series of cards consists of the PVR-150, PVR-250,
PVR-350 and PVR-500. The PVR-150 is a cost-reduced
version of the PVR-250, and the only basis for deciding
between them is cost. The PVR-350 has an MPEG-2
decoder on the card and can act as a video card. The
PVR-500 has two TV tuners on the one card and acts like
two PVR-250 cards. Hauppauge does offer multiple versions
of some of these cards, some with a remote control and some without, so
double-check what is or isn't included with the card before
you buy one. Also of note is the existence of one AverMedia card,
the M179, that can support the same MPEG-2 encoding tricks as
the Hauppauge PVR-150.

A large number of low-end TV tuner cards are available
from a large number of manufacturers, including
AverMedia and Hauppauge. They normally are built around the
Brooktree bt8xx or Phillips SAA71xx chips. When
looking for information about these parts, you
should keep in mind that Brooktree now is a part of
Conexant.

Besides low price, there are two common
elements to the Brooktree- and Phillips-based cards.
They depend on the main CPU to do the conversion to
MPEG-2, significantly increasing the sort of CPU you
need to support these cards. Second, almost all of
these cards depend on the sound card to digitize the
TV audio. Therefore, if you want to record two shows
at the same time, you need two audio cards.

MythTV does support selected USB and Firewire external
TV tuner boxes. So, if you hate the idea of opening up
your PC to install a PCI card, or if you have a laptop
PC where installing a PCI card is not an option, you
still can use MythTV. Do keep in mind, though, that you will
pay a substantial premium for these boxes, so if at
all possible, go with a PCI card solution. Finally, MythTV
does support some HDTV tuner cards.

As I noted in
a previous
article, I like nVidia-based video cards because of the quality
of the video driver software. Assuming you need a new
video card and have decided not to use a Hauppauge
PVR-350 card, the nVidia GeForce FX 5200-based
cards have received many good reviews in the MythTV
community. The GeForce FX 5200 is a poor
performer when it comes to 3-D video games, but it does
have four big things going for it: good software support, the ability
to handle anything MythTV can throw at it, low cost (its an
older card) and fan-less versions are available. If you are planning to set
up your MythTV box in a family room or living room, a fanless card may
prove critical. When watching TV, you want all of the noises you hear to
be part of what is happening on screen, not your computer.

What you need for a computer CPU depends on several
factors, starting with your TV capture card. The TV
capture cards that do MPEG-2 encoding on the cards themselves
place less strain on the CPU than do video
cards that handle MPEG-2 encoding through the main CPU.
Likewise, video cards that can do MPEG-2 decoding
on the card rather than through the main CPU are
easier to deal with. Still, a 750MHz Pentium III is about as low of
a machine as you want to go. Yes, you can get away with a lower-end machine
if you use high-end capture and video cards. But if you use basic
capture and video cards, you probably will find yourself needing a
higher-end CPU.

If you are building a MythTV box from scratch, you should give some
thought to the case. As with the video card, low noise is a consideration
for this project. Cases are available that offer sound muffling for a
price that may be worthwhile in some situations.
Here
you can find a list of real-world examples of the kinds of hardware that
have been made to work and get some idea as to how happy the people in question
have been with the results.

What you are going to need in the way of software
depends on the hardware you have and where
you live. To start with, you need the MythTV
package, which contains the MythTV front-end and MythTV
back-end software. It is available on the
MythTV Web site. While
perusing the MythTV Web site, you likely will want the desirable but not
required plugins package, which adds support for weather displays, games
and other useful additions.

MythTV depends on its database, which runs under
MySQL, so the next stop is the
MySQL Web site.
MySQL is offered under two licenses, a commercial one and a
free GPL one. For MythTV purposes, the GPL version is fine and should be
downloaded and installed.

Driver software is required for your TV capture device(s). Exactly what
you need here depends on the device(s) in question. For the Hauppauge
PVR series, you need the
IVTV driver.
For drivers and information about a number of other TV
tuner cards, take a look at
the
video4linux wiki.

One of the nice features of all self-respecting PVRs is
the ability to point and click what shows you want
to record. This means MythTV needs to somehow know
when/where, for example. Doctor Who or
Corner Gas will be shown. If you are in the United States or
Canada, you should set up an account with
Zap2it Labs. It provides a TV listing
service for MythTV users, the only requirement being
that you complete a short survey every 3 months.

When setting up an account with Zap2it, you need to
answer some user-profile questions, such as how many
hours do you spend reading each week. You also need to
provide some location information, your zip/postal code,
antenna/cable/satellite provider name, plus the
MythTV certificate code: ZIYN-DQZO-SBUT. If you live
outside the US or Canada, instead of using Zap2it, you
need a copy of XMLTV. XMLTV is a program that, as of this writing,
can grab TV listings for Austria, Britain, Denmark, Ireland, Finland, France, Germany,
Hungary, Japan, Netherlands, Norway, Romania, Spain
and Sweden from local Web sites. It then turns the listings into a
format that MythTV is happy with.

To support the ability to use a TV-style remote
control with MythTV, you need a copy of the
Linux Infrared Remote Control
(LIRC) software and some sort of infrared detector for your PC. Depending on the sort of TV
capture card you choose, an infrared detector may have
been included. Alternatively, if you're comfortable
working with a 25-40 watt soldering iron, the
LIRC Web site has plans for several simple infrared
detectors that work well with its software.

For the remote control, if you don't use the
remote included with your TV tuner card, then almost
any "universal" remote control can be made to work
with the LIRC software. The one brand of remotes
with known issues is Bang & Olufsen, which uses a
proprietary protocol. In my case, I was able to get a
perfectly usable, factory refurbished remote and a
package of batteries from a local electronics clearance shop,
all for under $5.

Next comes the installation. As previously noted, this step
is going to be tough, with a number of distribution-related
oddities. So, you are going to need help beyond what is included with
the software or what is available on the
MythTV Web site. Jarod Wilson
wrote an excellent
on-line guide for setting up MythTV
under Fedora Core 4.
This
MythTV users mailing list is useful, but at around 100 messages
a day, is somewhat high volume. In addition, the major search engines such as Google
and Yahoo are your friends in tasks such as this one. You almost can be certain
that someone somewhere has encountered the same problem you're now facing and has
posted a note about it on the Net. [Also, check out the
December 2005
issue of Linux Journal for more articles about
MythTV.--Eds.]

If you choose to set up a remote front-end box that
does only the display work, while depending on a back-end
box for files and TV capture cards, there is some
debate as to what makes the best front-end box. Ironically, Microsoft XBox video game
machines are a popular choice for a front end, as they can be made to
run Linux.
XBox machines are small, and they blend in well with a
family room decor. More importantly, they have almost all of the key
hardware you would need for a front-end box, such as
built-in network connections. And, with the November 2005
release of the XBox 360, used original XBox machines
should be inexpensive.

Beyond the basic install, the MythTV plugins offer a
great many goodies. There are two legal issues to be
aware of with two of the plugins, MythDVD and MythGame.
In order to be able to watch properly the DVDs you
have bought or rented from the local video store, you
need a program that can deal with the Content
Scrambling System, or CSS. CSS is the encryption system used on
a great many DVDs that supposedly prevents DVD
piracy. The movie studios have been all too happy to
sue software developers who develop open-source CSS
software or even those who provide links to where you
can find CSS software. Still, as noted, when you run
into a problem with getting something to work with
MythTV, search engines are your friend.

Other legal issues can come up with MythGame, which
uses
Xmame to allow you to play old
video arcade games. Xmame mimics the hardware of old
machines and can support over 3,000 games. After all, a 3GHz, 64-bit
PC has no trouble mimicking 25-year-old, 1MHz, 8-bit video game hardware. The old
video game software for Xmame can be an issue, though, as all
of it still is under copyright. Thus, there can be
issues running it under Linux. Copyright holders for two games,
Gridlee and Robbie Roto,
have given their permission for non-commercial use of these games.
In addition, the copyright holder for the game
Poly-Play, VEB Polytechnik
Karl-Marx-Stadt, disappeared in the collapse of East Germany,
and the game is treated as being public domain.
Before you legally can play the thousands of other old
games available, you need to get the ROMs that originally were
shipped with the game. Once you have an original set of, say,
Battlezone, Space Invaders or
Asteroids ROMs, you can in most jurisdictions legally
make a backup copy to your PC and then run the backup copy on your PC.

Colin McGregor (colin@mcgregor.org) works
for a Toronto area charity, does consulting on the side and
has served as President of the Toronto Free-Net. He
also is secretary for and occasional guest speaker at the
Greater Toronto Area Linux User Group meetings.