Building a home media center with MythTV
TV in Linux
MythTV and its extensive ecosystem of add-ons let you turn your Linux computer into a full-featured home
media center.
By PATRICK DAVILA
Joachim Angeltun, Fotolia
MythTV is a collection of software tools for TV in Linux. The MythTV website [1] calls MythTV "a
GPL-licensed suite of programs that allow you to build a mythical home media convergence box on your own
using Open Source software and operating systems." MythTV provides an interface from your computer to
your cable or satellite television service. You can use MythTV to pause, rewind, or fast forward television
programs. MythTV with a video capture card lets you record TV programs. And MythTV runs on a
network-ready Linux system, so you can configure several front-end devices in your house to view and access
a common set of video resources.
At first glance, MythTV looks like nothing more than a Open Source clone of Tivo - a hard-disk-based video
recorder that's basically a digital version of a VCR. But MythTV offers much more functionality than Tivo.
Yes, it can record, pause, and playback your favorite TV shows, but it also offers a huge suite of add-on
applications that can do much more. Also, because MythTV is an Open Source project, it is not
feature-encumbered like many of the commercial DVR systems. For example, MythTV provides automatic
commercial skipping. On the other hand, although you used to be able to hack your Tivo to skip commercials,
Tivo is now implementing flash-based pop-up advertisements that will display when the user is fast
forwarding.
The MythTV project was started by Isaac Richards in 2002 and has developed into a very active community
that is constantly implementing new features and add-ons. (See the box titled "MythTV Add-ons.") These
features make MythTV the first true home media center. Best of all it, was developed and implemented
entirely on Linux. Ports of MythTV also exist for Apple OSX and FreeBSD.
TV in Linux 1
Figure 1: From the outside, my home-built MythTV box looks like a standard home media device.
Figure 2: The inside of my MythTV box looks much more like an ordinary PC.
MythTV Add-ons
The current list of MyTV add-on applications is quite impressive:
" Myth Browser - web browser
" Myth DVD - DVD manager/player that lets you rip DVDs
" Myth Flix - view your movie queue from Netflix (popular on-line movie rental
service)
" Myth Gallery - photograph manager/viewer
" Myth Game - play your favorite old school video games via game emulation
" Myth Music - audio file manager/player that lets you rips CD s into your favorite
formats
" Myth News - RSS feed reader
" Myth Phone - SIP based VOIP
" Myth Stream - listen to streaming audio content from the internet
" Myth Stream TV - stream your TV recordings over your network via VLC
" Myth Video - video player for files not recorded via MythTV
TV in Linux 2
" Myth Weather - weather forecasts for your local area
" Myth Web - control the scheduling of recordings via the web
" Myth Burn - archive recorded shows to DVD
Modular Design
The MythTV suite is modular in design. The main application includes a front end and a back end. The back
end is where the scheduling of recordings takes place. A MySQL database houses programming information
and catalogs recordings currently residing on the system. A user interacts with the application through the
front-end GUI. The front end may or may not reside on the same computer as the back end database. You
could build one master MythTV server that holds all of your digital media. Multiple clients could then access
the server over the network. Some creative MythTV client setups have included X-boxes and bootstrapped
diskless set top devices.
You can set up a dedicated MythTV server, or you can even set up MythTV on your main workstation and let
it act as the server portion of your home digital media center. You'll find numerous HowTo documents on
configuring MythTV with almost all of the popular Linux distributions (Debian, Fedora, Gentoo, Slackware,
Suse, Ubuntu, etc.). For this article, I will build a dedicated MythTV box that will act as both a client and
server. For this purpose, I will use a small, specialized PC that will reside with the rest of the audio/video
equipment inside of a stereo component rack.
Getting the Hardware
The heart of a MythTV box is the TV tuner card. MythTV is flexible enough to use anything from raw video
capture cards (that do not encode the video) to high definition cards. Although raw tuners cards such as those
based on the BT878 chipset are the cheapest, they will be the most taxing to your system. All the encoding
will be done by the CPU. This may be an issue if you want to watch a previously recorded show while
recording another program.
The solution to this problem is to use a hardware-based encoder card that will encode the captured video
signal on the fly to a standardized video format. MPEG2 is the current standard video compression format
used around the world. The biggest drawback of MPEG2 files is that they are quite large. 1 hour of high
quality standard definition video will be about 1 Gig in size. The biggest plus for hardware-based encoder
cards is that they will only use about 4--8% of the CPU. Thus you can continue to use your system for other
tasks while it's recording TV programs. Currently, high definition TV sets and recorders are still fairly
expensive, even though high definition capture cards are relatively cheap. (See the box titled "High Definition
Capture Cards.")
Since I currently don't own a high definition TV set, I chose to go the standard definition route. Unlike the
commercial DVR products currently available on the market, you can upgrade your MythTV system to a high
definition setup when it becomes feasible.
The most popular brand of standard definition encoder cards is Hauppauge. The Hauppauge 500 comes with
two encoder chips and sells for about US$ 160. Two encoder chips are useful if you want to watch a program
that is different from the one you're recording. The Hauppauge 250 comes with a single encoder chip and sells
for about US$ 130. In addition to one encoder chip, the Hauppauge 350 also comes with a decoder chip. This
saves considerable resources when playing back recordings. The 350 model also comes with a combined A/V
connection, breakout cable (with S-Video, composite video, and stereo audio out) and FM radio receiver and
antennae. The 350 sells for about US$ 160. The newest model from Hauppauge is the 150, which is very
similar in function to the 250 and sells for about half the cost.
All of the aforementioned Hauppauge cards are extensively supported in Linux by the ivtv driver. With the
exception of the MCE version of the Hauppauge 150, all Hauppauge cards usually come with remote controls,
along with an infrared receiver for the encoder card.
TV in Linux 3
One of the main requirements for my MythTV box is that it's the center of my home theater setup. Yes, you
can use a standard PC tower case, but it won't be very aesthetically pleasing. Therefore, the case should look
like it belongs in the stereo cabinet with rest of your A/V components. I settled on a black Cooler Master
ATC-620 case, which fits perfectly in my component stereo rack. Since I decided on a Mini-ATX case, I went
and purchased an MSI 651M motherboard.
The next question is how much horsepower do you need to run MythTV? The very first time I tried out
MythTV, I used a Hauppauge 350 card with an 800 Mhz Intel Pentium 3. I was able to get away with this
because of the decoder chip the 350 uses. These days, processors are relatively inexpensive. If you're going to
have the CPU handle playback, you should get at least a 1.5 GHz processor.
I installed 512 MB memory on my system even though the minimum requirement is 256 MB. One area where
you shouldn't hold back in spending is hard drive capacity. Basically, more is better. I recommend getting at
least a 200 GB hard drive - especially since hard drive prices are dropping quickly. 1 GB video files will chew
up your hard drive space fairly quickly.
The good news is you can always add more hard drives later. Although a DVD burner is not required, a burner
will come in handy if you'd like to archive some of your favorite recordings. Another area where you
shouldn't be miserly is a higher quality silent power supply. This is especially true if you need to power
multiple drives. In my past experiences, a cheap power supply is usually the first component to fail in
a system.
Video card requirements are fairly light with MythTV. I picked up a used NVidia card for about US$ 20. The
card has an S-video out for my TV connection. If you're using a Hauppauge 350 card and don't need any 3D
acceleration, stick with the motherboard's on-board video. If you plan on connecting your MythTV box to
your home network wirelessly, use at least a 802.11g network card. 802.11b will not be fast enough to stream
large video files.
Buying the Box
Cost of MythTV box components:
" MSI 651M-L motherboard US$ 25 (EUR 20)
" 2.4 Ghz Intel Celeron processor with fan US$ 50 (EUR 39)
" 512 MB memory (PC3200) US$ 40 (EUR 31)
" 250 GB 7200RPM hard drive US$ 80 (EUR 62)
" Hauppauge WinTV DVR 150 card US$ 60 (EUR 47)
" Geforce MX440 AGP video card with video out US$ 20 (EUR 16)
" Cooler Master ATC-620C Micro ATX case: US$ 75 (EUR 58)
" Ultra silent 300 watt CMAX power supply US$ 30 (EUR 23)
" NEC Dual Layer DVD burner US$ 40 (EUR 31)
" Lite-On wireless keyboard US$ 15 (EUR 12)
Total cost: US$ 435 (EUR 339)
Costs of comparable commercial offerings:
" Tivo: US$ 255-355: US$ 100-200 + US$ 155 (yearly guide subscription fee)
TV in Linux 4
" HP z545 Digital Entertainment System: US$ 1,800 (runs with Microsoft Windows Media
edition)
" Alienware DHS System: US$ 1,600 (runs with Microsoft Windows Media edition)
High Definition Capture Cards
Some examples of high definition capture cards include:
" Air2PC PCI (8VSB)
" pcHDTV-2000 (8VSB)
" Air2PC HD5000 (8VSB, QAM256) - US$ 120 (EUR 95)
" pcHDTV-3000 (8VSB, QAM256) - US$ 170 (EUR 135)
" dvico Fusion HDTV Lite 5 (8VSB, QAM256) - US$ 120
(EUR 95)
Programming Guide
You'll need a service on the Internet that provide television programming information. If you are located in
North America, for instance, you may want to set up an account with zap2it [2]. This account will be used by
MythTV to pull down all the TV programming information that is stored in the database. zap2it is kind
enough not to charge anything to the MythTV community for this service, but in fact, zap2it provides the
same service to many of the commercial DVR products for a fee.
Go to the website http://labs.zap2it.com and enter the following code:
'ZIYN-DQZO-SBUT'
You will then be prompted to create a user name and password. Write these down, as you will need them
during the installation process.
If you live outside of North America you will need to setup XMLTV, and you may have to do additional
configuration, depending on the country where you reside. Please check the MythTV wiki on XMLTV for
your options [3].
Installing MythTV via KnoppMyth
KnoppMyth is the easiest way to setup a dedicated MythTV box [4]. The KnoppMyth distribution is based on
Debian and uses the auto-detection scripts based on the Knoppix live CD distribution. Before starting the
installation process, it is very important to investigate how you will import TV listings into your system.
At the first prompt, you can get the option of doing an auto install, running as a front end, doing an upgrade,
or doing a manual install. For most people, the auto install is sufficient. On multiple occasions, you will be
presented with a warning that your hard drive will be completely re-written. The installer will then ask you to
set up a regular user ID in addition to a root password.
Another final warning gives you the option to quit the install. The installer scripts then start off by partitioning
your hard drive and setting up a customized version of Debian running the 2.6 kernel. After the initial
installation, the system reboots. At this point, the driver has been set up for your Hauppauge capture card
along with accelerated 3D drivers for NVidia graphics card owners.
Upon the first login, you are prompted to sign on as root and complete the MythTV configuration process.
You first need to finish your network configuration by deciding if you want static or dynamic IP addresses.
You are then presented with the option of configuring your remote control. You can select from 42+ brands of
TV in Linux 5
remote controls, including the ones bundled with the Hauppauge capture cards. If you make a mistake
configuring your remote, you can simply rerun the setup script at anytime by typing:
#: /usr/local/bin/lirc-reconfig.sh
You are then asked if you want to add additional i686 modules; if not, you can go with the default settings.
The script then goes about installing the main MythTV add-on modules.
The main myth-setup script starts up and asks you to enter your language preferences. You then need to do
some general MythTV configuration:
" General - has the IP addresses for your back-end server and ports that MythTV will run on. If your
MythTV box will serve as a both a front and back end system, leave the defaults (IP address of
127.0.0.1, etc.). The next screen will have TV format (NTSC or PAL) and channel frequency settings
(us-cable, us-bcast, us-cable-hrc, us-cable-irc, japan-bcast, japan-cable, europe-west, europe-east,
italy, newzealand, australia, ireland, france, china-bcast, southafrica, argentina, australia-optus). The
next couple of screens will have some back-end job options, such as if you want to use autostart and
transcode after recording shows.
" Capture cards - Select new capture card. You must then enter a supported card type (analog V4L
card, MJPEG cards such as Matrox G200, MPEG-2 encoder cards such as the Hauppauge line, DVB
DTV cards, pcHDTV DTV cards, firewire cable box, USB MPEG-4 devices such as Plextor
ConvertX, and Dbox2 TCP/IP cable box).
" Video sources - Select a new video source. Enter a generic name and select the appropriate XMLTV
listings grabber. For North America, select DataDirect. Then enter your user ID and password you
created at the zap2it registration site. Hit enter; the setup script then retrieves your channel lineup and
populates the database with the appropriate cable/satellite provider system information. You will then
need to select an input connection. Select tuner and match it to the name you provided for your
listings profile. It will then scan your TV card for active channels based upon your XML listings
preferences.
European Users will have to make several key changes in the mythtv-setup:
" TV format = PAL
" VBI Format = PAL Teletext
" Channel Frequency table = europe-west
You need to adjust the screen size from the recording profiles setup screen: Main Menu | Setup | TV |
Recording profiles.
The profiles need to have the height changed from 576 to 480 and the width changed from 480 to 720. In the
/etc/mythtv/modules/ivtv file, tuner type=1 has to be replaced with tuner type=5. You'll also need to add the
following entry:
rmmod tveeprom modprobe tveeprom dmesg
And /etc/sysconfig/ivtv/cfg should have the following:
IVTV_TUNER=X IVTV_TYPE='PAL'
X is the tuner type and should be replaced with the appropriate value.
After the initial setup is complete, you will see a message about running mythfilldatabase to populate your
back end database. Knoppmyth then automatically tries to configure your Mythweather settings based upon
TV in Linux 6
your provider's system area. The installer will then automatically run the mythfilldatabase command, which
fills the database with two weeks worth of programming schedules.
Once that's done, MythTV will startup for the first time. You will then see a message about pre-scaling theme
images and the front-end GUI becomes active. You are now ready to start using MythTV. At anytime, you
can rerun the MythTV setup interfaces by issuing the following command:
mythtv-setup
TV Standards
Depending on your location, you may wish to try one of the following "TVStandard" values:
" "PAL-B" - used in Belgium, Denmark, Finland, Germany, Guinea, Hong Kong, India, Indonesia,
Italy, Malaysia, The Netherlands, Norway, Portugal, Singapore, Spain, Sweden, and Switzerland
" "PAL-D" - used in China and North Korea
" "PAL-G" - used in Denmark, Finland, Germany, Italy, Malaysia, The Netherlands, Norway,
Portugal, Spain, Sweden, and Switzerland
" "PAL-H" - used in Belgium
" "PAL-I" - used in Hong Kong and United Kingdom
" "PAL-K1" - used in Guinea
" "PAL-M" - used in Brazil
" "PAL-N" - used in France, Paraguay, and Uruguay
" "PAL-NC" - used in Argentina
" "NTSC-J" - used in Japan
" "NTSC-M" - used in Canada, Chile, Colombia, Costa Rica, Ecuador, Haiti, Honduras, Mexico,
Panama, Puerto Rico, South Korea, Taiwan, United States of America, and Venezuela
The Video Signal
The quality of the signal is determined by the quality of the TV capture card you purchased for your system. If
you decide to purchase the more expensive Hauppauge 350, you will have a very good video connection that
will need some manual configuration. Basically you will need to have the video piped out to a frame buffer
device [5] [6].
If you purchase the less expensive Hauppauge 250 or 150, you will need a video card with a video out
connection. The low end NVidia MX420/440 is relatively cheap. You will have to slightly modify your
Xorg/XF86 configuration file. My file has the following settings:
Section "Device"
Identifier "Videocard0"
Driver "nvidia"
VendorName "EFX"
BoardName "nVidia GeForce 4 MX 420"
#TV Out
Option "TVStandard" "NTSC-M"
Option "TVOutFormat" "SVIDEO"
EndSection
TV in Linux 7
My file also contains the settings shown in Listing 1 to specify a television set.
Listing 1: Specifying a Television Set
01 Section "Screen"
02 Identifier "Screen0"
03 Device "Videocard0"
04 Monitor "Monitor0"
05 DefaultDepth 24
06 SubSection "Display"
07 Depth 24
08 Modes "1024x768" "800x600" "640x480"
09 EndSubSection
10 EndSection
11 Section "Monitor"
12 Identifier "Monitor0"
13 VendorName "Monitor Vendor"
14 ModelName "32in Analog TV"
15 HorizSync 30.0 - 50.0
16 VertRefresh 60.0 - 60.0
17 Option "dpms"
18 EndSection
The Cable or Satellite Receiver
If you use a digital cable or satellite television system, you will have to configure a serial port infrared blaster.
An IR-blaster tricks the cable/satellite box into thinking the user is changing the channels via the receivers
remote control. You can construct your own IR-blaster if you're moderately handy with a soldering gun, or
you can purchase a pre-assembled IR-blaster at a minimal cost from [7].
The current version of KnoppMyth (R5B7) has an option to configure an IR-blaster. Unfortunately, this
feature does not work correctly. To remedy this, Greg Frost has posted a work around in the mysettopbox
forums [8].
An out-of-the-box solution to this problem is in development for the next release of KnoppMyth.
In a nutshell, you will need to create a second instance of LIRC or some equivalent script to run at startup.
You will then need to create a script that will change the channels on the receiver. Different cable/satellite
boxes will require slightly different configurations, depending on the manufacturer make and model.
For non KnoppMyth setups, you can follow the guide at [9], which is fairly distribution neutral.
Day to Day
If you've familiar with Tivo or other commercial DVR systems, the menus in MythTV look very familiar.
From the main menu (Figure 3), you can go watch live TV, schedule upcoming recordings, and go into the
different add-on applications.
TV in Linux 8
Figure 3: MythTV provides a simple and practical main menu for managing media content options.
When watching live TV, you can pull up the system menu with the m key and browse what's on other
channels. You will then be able to view the transparent on-line guide while your show is still viewable. You
can scroll right and see what will be the channel you're currently viewing. You can also move up and down to
see what's on the other channels. This is similar to viewing programming guides on a digital cable or satellite
system.
Scheduling recordings is very easy. Go into the Schedule Recordings menu item and browse the program
guide. The database typically holds two weeks worth of programming information, so setting up recordings
for while you're on vacation shouldn't be a problem.
You can also find a particular show by using the search function. When you select a program to be recorded,
you have the option of making it record at regular intervals (similar to the season pass feature in Tivo) or as a
one time instance.
For setting up your audio collection, you start by listing the default directory where your audio files will
reside MythTV/Utilities/Setup/Media Settings/Music Settings. You can then copy your music collection into
the music directory remotely via SSH or fish in Konqueror.
You can also rip and encode new CDs by selecting import CD from the main music menu. You have the
option of encoding your ripped songs to either OGG, MP3 or FLAC. You can also create music play lists or
have MythMusic play random songs. MythWeather will display your local weather forecast, along with screen
captures of Doppler radar for your local region (Figure 4). (This feature is based on an interface with the
Weather Channel website.)
TV in Linux 9
Figure 4: The MythWeather add-on offers weather information courtesy of the Weather Channel.
If the location is incorrect, you can change it in the setup menu Utilities/Setup | Setup | Info Center Settings |
Weather Settings. MythVideo allows the playback of a multitude of video codecs (mpeg, avi, divx, xvid, qt,
wmv, etc..) by using Mplayer on the back end. MythDVD allows you to rip and store your DVD collection to
your hard drive. This feature is convenient if you hate having to go searching for the same DVDs over and
over again. For the retro gaming enthusiasts, there's MythGame, which allows you to run old ROM images of
Atari and NES games via the MAME and SNES emulators. Legally you are required to own the actual ROM
cartridges, even though there are numerous websites allowing downloads of all your favorite classic games.
One of the newest add-on applications is MythStreamTV, which allows you to stream your videos over the
network. Streaming is great if you want to take a break from a long night of coding and watch a recorded
program from your workstation.
By far the most impressive of the add-on applications is MythWeb. MythWeb allows you to interface with
your MythTV box over the Internet (Figure 5). Basically, an Apache web server is setup with access given
only to your regular user ID. You can view the program schedule, delete old shows, schedule new shows, and
even control streaming video via MythStreamTV. The only caveat to external access is forwarding port 80
through your network firewall. This feature is especially useful if you're on the road and want to make sure
your favorite TV shows will be recorded for you. MythTVBurn is a fairly new add-on application that is
especially useful if you have a DVD burner in your Myth box. The program lets you take previously recorded
programs and burn them to DVD.
Figure 5: MythWeb lets you connect to your MythTV box from over the Internet.
Figure 6: With MythTV, you can even search the web while watching television.
TV in Linux 10
Adding Storage Space
If you get to the point where you're running out of disk space and refuse to archive old shows to DVD, you
can add an additional hard drive. The best solution for adding more hard drive space is using LVM (Logical
Volume Manager). For all intents and purposes, hard drives set up with LVM will be treated by the system as
single hard drive partitions. You will have to backup any programs you've recorded, as they will be wiped out
when setting up LVM. This is because you are reformatting the partitions where your video files will reside.
Setting up LVM would normally involve many steps, but the developers of KnoppMyth have created a script
to simplify the process. To set up LVM, log into a console session as root and use cfdisk to create a partition
on your new hard drive called /dev/hdb1. Then run the create_lvm.sh script and pass the partition names you
want to combine:
create_lvm.sh /dev/hda3 /dev/hdb1
For SCSI disks, use the following command:
create_lvm.sh /dev/sda3 /dev/sdb1
The script will create disk volumes and modify the /etc/fstab file with the new partitions. This script should be
started by the command create_lvm.sh followed by the list of devices (partitions) to be included in the volume
group.
The next step is to umount the /dev/vg/myth partition:
umount /myth
Then format the /dev/vg/myth partition with the file system of your choice :
mke2fs -j -O sparse_super -m0 -i8000000 -L myth /dev/vg/myth
Remount the /myth partition:
mount /myth
And restore any files that were destroyed in the LVM formating process.
Conclusion
MythTV is an incredibly powerful application that let's you do everything a commercial DVR can do and
much more. The power of MythTV lies in the fact that MythTV enables users and developers to come up with
new and innovative ways to improve and extend its functionality. The MythTV project is not limited by
corporate monetary interests or constrained by development teams who are told what to work on. The only
possible obstacle is small minded legislation paid for by the entertainment industry that would outlaw digital
recordings for personal fair use. But alas, that is an argument for another day.
INFO
[1] MythTV: http://www.mythtv.org/
[2] Zap2It: http://www.zap2it.com/
[3] MythTV wiki on XMLTV: http://www.mythtv.org/wiki/index.php/XMLTV
[4] KnoppMyth: http://knoppmythwiki.org
[5] Hauppauge 350 with KnoppMyth:
http://knoppmythwiki.org/index.php?page=HauppaugeThreeFiftyInstallation
[6] IVTV driver install: http://mythtv.org/wiki/index.php/IVTV_Installl
[7] IR-blaster: http://www.irblaster.info/
[8] IR-blaster workaround:
http://mysettopbox.tv/phpBB2/viewtopic.php?t=9352&postdays=0&postorder=asc&start=0
TV in Linux 11
[9] MythTV with LIRC:
http://losdos.dyndns.org:8080/public/mythtv-info/MythTV_DISH_IR_LED_TX_via_Modified_LIRC.html
[10] Linux HTPC Howto: http://www.linuxis.us/linux/media/howto/linux-htpc
TV in Linux 12
Wyszukiwarka
Podobne podstrony:
2006 10 Idle Cycles Building Distributed Applications with Boinc2006 04 Images of the Empire Msn Messenger in Linux with Webcam Support2006 10 Skrypty powłoki w systemie Linux [Poczatkujacy]2009 05 Many Listeners Exploring Multicast Ip in LinuxLoathing Lupper in Linux2009 10 Playing Fetch Building a Dedicated Download System with RtorrentFabryka dźwięków syntetycznych 2010 10 26 In The Mix vol 3 dot dot2006 10 Przegląd modeli cyklu życia oprogramowania [Inzynieria Oprogramowania]us iraq int sum 2006 10 25Identity management in Linux and UNIX environments10 Late in the evening2006 10 Łączenie kodu C z zarządzanym kodem NET [Inzynieria Oprogramowania]2006 gene therpay in sport Br J Sports MedGemmologia 2006 10 Il Taglio Delle Gemmewięcej podobnych podstron