Last time, I promised to write something about how all of his works together
instead of continuing with the installation notes. While I haven't yet figured
out every detail of the whole system, this is what I'm going to do today.
Read
on...
Components
My system consists of a fairly standard Athlon PC equipped with a TechniSat
AirStar 2 TV PCI card giving it DVB-T television reception. This card is
capable of receiving free-to-air (unencrypted) channels, but not those which
require a Conax card to decode. I'm planning to later add a second card with
support for this purpose. Another note about the card is that it's of the
budget variety with no MPEG-2 decoding functionalities - this actually makes it
a better choice for a system like this, given that any modern CPU will be more
than capable enough to perform the decoding in software, especially when
assisted by a decent video card.
For the display, I'm using the Sanyo PLV-Z1 video projector I bought last
spring.
To go with the hardware, I've installed Fedora Core 3 Linux and the MythTV
suite, most easily available via ATrpms, a
repository of software maintained by Axel Thimm. The other alternative would be
to use KnoppMyth, which
in fact contains a complete system installation. I did not use this as I
repurposed the computer from our workroom PC, and did not want to reinstall it
completely.
The DVB card came with a simple remote control, the configuration of which
was included in LIRC, which is what all
Linux programs use for remote control support.
Viewing and recording TV
The main function of the system is of course viewing and recording TV
broadcast. After spending some time going through various deadends trying to
make MythTV understand the DVB driver, I stumbled upon the real solution:
Zap2Myth. This program takes
a list of channels from the tzap program (which is able to find them
automatically), and converts that to MythTV's format as an SQL script which you
can insert into the MythTV backend database. The process could have been a lot
more clear, and in fact I think MythTV should use tzap directly to handle DVB
reception, but eventually I did succeed in the installation.
The results are mostly very satisfying, with excellent image quality,
comparable to the best digital TV set-top boxes. Not completely so, however.
Trying to switch to a channel which is not currently broadcasting can freeze
MythTV, requiring me to either wait for a timeout to occur, or to restart the
software. A couple of times this has actually crashed the backend, requiring a
restart. I have not been able to get subtitles to work either - this is a
problem that affects many DVB-T set-top boxes and is due to the Finnish
broadcasts being slightly different than in other (larger) markets. I get the
feeling MythTV has not been completely tuned for DVB reception, and these
glitches would not appear with analog channels.
As an aside: MythTV consists of two linked parts. The backend is in charge
of receiving broadcasts, scheduling recordings and storage, while the frontend
provides the on-screen menus and viewing capabilities. This split makes it
possible to build a solution where the storage is done by a separate computer
hidden in another room, and the living-room frontend is a smaller device. In
fact, it is a commonplace solution to connect multiple frontends to the same
backend, for viewing the same video archive from multiple rooms for instance.
In my case, the backend and frontend are on the same box, although I have
additionally configured another frontend on my laptop for casual viewing.
Selecting programs to watch or record is done via an easy-to-use
program guide, immediately familiar to anyone who's used a Tivo device or most
other set-top boxes. This program guide pulls in program information from
public web sites via a program called XMLTV. Its
coverage of Finnish TV channels is via the Katso! web site. Using channel information from
Telkku.com or Ohjelmat.info would however sometimes give
better coverage. For the most part, this is a satisfactory solution anyway.
With one DVB-T card, I can watch or record one live broadcast at a time. In
fact, due to the way DVB broadcasts are made, it would be possible to do more,
as is shown by another software package the name of VDR. MythTV does have patches for similar
functionality, but these have not been integrated to the package yet. However,
MythTV will be able to utilise as many reception cards you install, and I plan
to later install a second DVB card with pay-channel support via a Conax decode
card and an analog TV card for receiving a couple of satellite channels from
our building's common satellite dish.
DVD
Another goal of this project was to reduce the height of our hifi stack.
We've already eliminated the VCR, and eliminating the DVD player as well should
be quite easy.
Again, annoying glitches did make this somewhat more work than I expected.
MythTV by default utilises a program called MPlayer to provide it with playback
capabilities. MPlayer is a wonderfully versatile package, able to display
nearly any formats imaginable, with excellent video quality through its
postprocessing capabilities. However, DVD playback is lacking one crucially
important feature: support for DVD menus. This resulted in most DVD discs
showing nothing but a blank screen.
However, the solution to this was to reconfigure MythTV to use another media
player for DVD playback. I used Xine, although
I could have chosen Ogle
as well. Both of these have very robust DVD support. The lack of "boxed"
integration does mean that I still have to additionally reconfigure Xine's
keyboard commands to match to MythTV's so that the remote control will work as
expected.
Music
VCR and DVD player eliminated, lets turn our sights to the CD changer. Since
the computer I'm building this on is our old workroom computer, it already had
most of our CD collection on it in Ogg Vorbis format. Vorbis is a format
competing against MP3, AAC and others, distinctive by providing high quality in
low bitrate and at the same time being completely open source. It's gradually
getting more widespread market acceptance, with support in some portable
players such as the very cool iAudio M3 (christmas present,
anyone?).
MythTV supported this with no effort whatsoever via the MythMusic
system. Two wishlist items: it could have automatically found the music
collection (like for example Rhythmbox
and Zinf, but more importantly, it does not
have a very good music browsing/playlist management system. Combined with the
limitations of the remote control, this makes choosing music a bit of a job.
It's much better than the MP3-CD support of our DVD player, but falls very
short of the best desktop media players like iTunes or Rhythmbox.
Other functionalities
Now, we are talking about a PC, so the story certainly does not end here. We
have the following:
Commercial autoskip: On the second day after the installation of
MythTV, it already started to notify us while viewing recorded programs that a
commercial break is starting in a couple of seconds, offering to skip it
completely. This is a wonderful feature, and I can not really criticise it of
not always being 100% correct, as for the most part it does work very well, and
perfectly enhances the fast-forward and rewind functions you would expect to
have in a digital media center.
Editing recordings: Sometimes you want to archive shows for later
viewing, such as recently the last couple of episodes of Sopranos before its
Finnish broadcast break, so that we can watch them again before the show
returns. This is made perfect by the editing capabilities, allowing us to
remove commercials completely from the archived version (which of course can
also be re-encoded to DIVX format and burnt to CD-R for offline archiving).
Weather forecast: After telling MythTV that we live in Helsinki, it
started to pull weather forecasts complete wth satellite pictures from Weather.com,
providing a nicely presented, always up to date weather forecast a couple of
remote button presses away.
News: Naturally I can program the latest news broadcast to always be
recorded, but in addition MythTV will pull in the web-based news articles from
any sites I want. BBC, CNN, Dilbert...
Other video: Whether its home videos or stuff pulled from the net,
the system will show it all just like TV programming. I've enjoyed a couple of
episodes of MTV's Pimp My Ride this way recently.
Picture gallery: All of our digital pictures are stored on this box,
and MythTV includes a nice picture gallery component for watching slideshows on
our projector.
Further
The possibilities are endless. There's an extension to MythTV providing
classic arcade and console games via the MAME project that I have not yet tried. The built-in
web browser is perfect for casually checking a web site from time to time, or
regularly accessing MovieLens for
the latest movie recommendations. Although Linux doesn't have that many games
available for it, some of the best ones are perfect for living room
enjoyment..
Bottom line: MythTV provides us with an extremely versatile, and for the
most part nicely polished HTPC system, but it still is a bit too difficult to
set up, especially when using it for DVB reception in a small country like
Finland. Most people will get a more satisfactory experience by buying a
ready-made solution, but if you're willing to tinker, and have experience with
computers, this approach will give you much more than anything available in a
store.
Comment by Sylvain on Tue, 23 Aug 2005 06:16:55:
I also have a Sanyo PLV-Z1 and run MythTV. I was wondering if you were able to
drive it in its native resolution (964x544) from X? Thanks,
Sylvain
Comment by oa on Thu, 25 Aug 2005 10:30:03:
Check my latest entry, hopefully it'll help you along.
http://www.fishpool.org/archives/tech/200508/htpc_project_projector_and_remote_configurations.html
