[mythtv-users] Help creating a Not a Frequently Asked Questions page?

Kent Boortz kent at korthuset.com
Tue Sep 30 22:10:48 UTC 2008


Hi,

I want to build me a MythTV box, but I'm still a bit confused. I have
spent hours and hours searching for answers. It might just be me, but
some basic questions I can't find answers to.

Assuming others might feel the same, I'm suggesting a new kind of FAQ
page in the mythtv.org wiki, in form of a "MythTV Not a Frequent Asked
Questions", MythTV-NOTAFAQ. That tell "What can I really do with MythTV?",
"Is MythTV for me?", "Is it solid enough to replace my TV set?" and
other more basic questions.

I hope you find this a good idea, and to illustrate what I mean and
give a jump start, I have written some text below. My hope is that
some kind souls will fill it in with the *correct* answers :-)

The text below also lacks references, I hope the final page to have
lots of them. If you think this MythTV-NOTAFAQ is a good idea that is,

kent


------------------------------------------------------------------------------
Q: I have a "Windows computer", can I use MythTV?

MythTV in its full form, no. The recording hardware, like TV cards,
has to be connected to a computer that runs the Linux operating
system. You can with more or less trouble view the TV channels and
recorded content from both Windows and Mac OS X, but you still need a
home network and a separate computer that runs the Linux operating
system and MythTV.

------------------------------------------------------------------------------
Q: So can I install that Linux thing in Windows?

No, Linux replaces Windows. And, not to offend you, if you ask that
question MythTV will be a bit too complicated for you to install and
use.

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Q: I'm not used to Linux, can I install Linux and MythTV on my computer?

If all goes well and you use a Linux distribution that has MythTV as
its focus, yes, but in general you will likely get lost. Why not try
it out first, burn a MythTV Linux boot CD on your Windows computer,
and start the Linux operating system from the CD and there try out
MythTV? This will not destroy your Windows installation (unless you do
"something wrong"), it will just run Linux and MythTV directly from
your CD.

------------------------------------------------------------------------------
Q: I'm not a very experienced Linux user, can I set up MythTV?

Maybe, but see the answer about non Linux users above.

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Q: I already run Linux, can I install MythTV?

You might need to update the kernel, drivers, 3rd party libraries
etc, so depending on how new your Linux distribution is, it might
be easy or hard.

There are different players to make the TV card work, kernel version,
TV card driver kernel module, MythTV version, and library versions of
libraries MythTV uses. And to this "card revision". It is *always*
easier to use a Linux distribution targeted for creating a MythTV
setup.

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Q: On Windows TV cards "just work", why do I read about all the
   trouble people have using MythTV?

First of all, not all Windows TV cards work well even in Windows,
depending on hardware and drivers etc. But lets assume it does,
why is it harder on Linux?

There are several factors, a major one is that the drivers in Linux
often are written by volunteers without access to all documentation
about the hardware, and no access to the source for the Windows driver
by the vendor. It is hard to do a "perfect" driver if lacking the
needed information.

Another factor is that because Windows TV cards are in a volume
market, if the vendor can save a buck switching to a new chipset
revision or changing the design slightly, they will do it, and then
rewrite their drivers to fit the hardware. And this without renaming
the product. This means that for Linux you might be out of luck if you
have "revision N" of a know to work card, as your hardware is slightly
different from the one the Linux driver expects.

------------------------------------------------------------------------------
Q: What is this about "front-end" and "back-end"?

Think about it this way, the back-end contains your TV card and is
handling the disk storage for recorded content. You can have multiple
back-ends, might be needed if you run out of PCI slots for TV-cards or
if you use software encoding of recorded content that require lots of
CPU power.

You can also run multiple front-ends connected to these back-ends,
to view the video content on more than one computer.

Note that in a small setup you can run the front-end and back-end
on the same computer.

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Q: I have a great Linux box, but MythTV refuses to work, why, why?!

Welcome to the world of PC hardware :-) Unfortunately, while there is
a "PC standard" things sometimes doesn't work well. A PCI TV-card
might not work at all or badly in any of your PCI slot, or require to
be in a specific PCI slot. The TV-card might work but slow down your
machine almost to a halt, give weird picture, make other hardware not
work, or not work at all. Prepare to spend hours to move all your PCI
cards around until it works. Or to give up.

And even if you have a USB TV dongle your USB hardware might "not like
each other" and give trouble.

A kernel update or updated driver might help, but sometimes it just
doesn't work. Depending on who you bought from it might also be harder
to get your money back for the TV-card, as it might work in Windows,
and the manufacturer never said it would work with Linux.

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Q: Can I record and view at the same time?

Yes. You can even move around and view different parts of a show you
are still recording. Be prepared to become addicted to this "time
shifting" feature you never knew you wanted, you will never buy an
ordinary TV set again :-)

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Q: Can the same or different content be viewed from more
   than one computer i my local network at home?

Yes. But only one can switch channel on the same hardware TV-card. In
general MythTV gives as much flexibility as possible given your
specific hardware constraints [really? or some "master" concept?].

Note that these limitations can be confusing to the users at times
(see more about this below)

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Q: Is the MythTV user interface "family friendly"?

If you mean if it measure up to other "setup boxes", definitely yes.
If you mean if "it just works" from a user perspective, no solution
like this does to 100%. As you have a limited number of TV cards,
trying to do more than the hardware allow will always be a bit
confusing for those in the family that doesn't know about the deep
technical details. This is no different to all other electronic media
solutions.

As MythTV is so flexible and has such nice user interface, the
expectations might go up too high from the users in the family. But if
you set the expectations right (and don't scare them off by sharing
all the details of your struggle to do the initial hardware
configuration), MythTV will be a wonderful TV and video solutions to
you and all of your family!

------------------------------------------------------------------------------
Q: If viewing from another computer than the one connected
   to the TV-card, how fast must the network be?

Any normal home network should do, 10 Mbit/s and up. But a network
might be too loaded by other activity giving hickups in your viewing,
so faster is better. MythTV can't be given priority on the network,
the network protocol doesn't allow for that.

Wireless networks might get interrupted by other viewless interference
that you normally doesn't notice, but when viewing video you do. It
might help to force your wireless to use another SSID (channel).

Also note that the same apply for networks as for USB, some hardware
doesn't "like each other". Even with wired networking sometimes you
get very poor performance between a pair of hardware, so try the
connection with other network traffic before blaming MythTV. Moving
the cable to another switch/router often help.

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Q: Can I use my desktop computer to also do recordings from my TV-card?

Yes and no. Operating systems are not perfect, and as you might notice
already some activity might distort your sound for a second, or hight
CPU load might disturb your viewing of a MPEG movie. Even if you can
tell the operating system to prioritize the TV recording, you might
get hickups that disturb the recording, especially when other
"desktop" activity is going on, like viewing a Flash movie in your web
browser or running (god forbid to use such power hungry applications)
a word processor.

But if you don't mind risking some distortion of the recording, sure,
no problem, there is plenty of CPU power in a modern Linux desktop to
do the job.

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Q: Do I need hardware compression? In what situations will I *not* need it?

In most situations, you need hardware compression. In a very simple setup
you can get away without it, and let the CPU do the job for you. [Not much
of an answer.....]

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Q: How can the TV card video encoding hardware handle all the
   different formats I might want to save my recording in, like MPEG2,
   MPEG4, AVI......

First of all, some things you reference to as "video formats" are actually
just containers of "encoded video", i.e. even if having the file extension
".avi" what is inside the file might be encoded in different formats. The
inner format is often referenced to as "codec".

But you are right, a TV card with hardware compression often only have
the option to use one or two different codecs. This is enough unless
you run some professional recording studio with very specific needs.

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Q: Is it better to use the same tuners, brand or type, i.e. is it bad
   to mix different TV recording hardware?

MythTV doesn't mind, it will just need to know what features your
cards have, and it will use them in the best way possible.

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Q: I want to have 4 tuners, what is the best option, PCI or external
   tuners with USB?



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