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

[Dan Ritter]

On Wed, Oct 01, 2008 at 12:10:48AM +0200, Kent Boortz wrote:
> ------------------------------------------------------------------------------
> 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.....]

If you are recording from an analog source, you can use a
software encoding tuner which uses your CPU. It's very cheap.
You can also use a hardware encoding tuner, which won't load
your CPU much -- likely about 2%. If you have (or want) multiple
tuners, that's the way to go.

If you are recording from a digital source, the question is
meaningless. You can do a software transcode later to move the
video into a different format (DVD, AVI, DIVX, for your iPOD,
etc.)

> ------------------------------------------------------------------------------
> Q: I want to have 4 tuners, what is the best option, PCI or external
>    tuners with USB?
> 
> >From a compatibility standpoint, expected trouble.....
> 
> CPU load.......
> 
> Cost.......
> 
> [Yes, I want to know?]

USB and ethernet-attached tuners are usually the easiest to set
up. That said, there's not that much to do for PCI tuners, and
the difficulties in FireWire tuners are mostly your cable
company's fault.

If you are using a PCI tuner, it's probably best to avoid a
VIA-based motherboard.

> ------------------------------------------------------------------------------
> Q: Can I connect one or more external USB TV dongles to an USB hub?

Yes, but you'll need to watch the overall bandwidth of that
connection. USB isn't as good as FireWire at allocating
bandwidth fairly, which is one of the reasons that new
motherboards often have six or ten or a dozen USB ports.

> ------------------------------------------------------------------------------
> Q: In practice, how many cards/channels can I record at the same time on
>    one single back-end?
> 
> The DVB-T stream is already compressed, so storing it is just about PCI/USB
> bandwidth and how fast you can store it on disk. As a rule of thumb....

As a rule of thumb, one disk is good for two streams. If you
have four disks, you can probably record 6-7 programs and watch
another one.

Analog non-compressing tuners will chew up more CPU time than
disk bandwidth.

-dsr-

-- 
http://tao.merseine.nu/~dsr/eula.html is hereby incorporated by reference.

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