[mythtv-users] ITX vs ATX for dual-DVB system

Stutty stutty at gmail.com
Mon Oct 10 21:16:25 UTC 2005


On 10/10/05, Jules Bean <jules at jellybean.co.uk> wrote:

> In principle, given enough memory the livetv could be without hard disk,
> couldn't it? Just put the ringbuffer on a tmpfs filesystem? (How big is
> the ringbuffer) And then sort out the ACPI stuff so it can turn off the
> disks. Which hard disk was it, anyway? I'm looking at a 300G SATA maxtor
> which is 26dB - as far as i can tell, 26dB should be just about
> inaudible once put into a good quality case.

The 26dB figure is misleading, visit
http://www.silentpcreview.com/article29-page1.html for more info.

I've got a SAMSUNG 160GB spinpoint (PATA), which is actually very very
quiet, but because I have no fans in the case, it can't be
acoustically insulated, in fact it is better if it is fitted to the
sides of the case (which act as a heat sink). This unfortunately means
the drive vibrations get amplified by the case and then by the wooden
TV unit it sits on!

The size of the ringbuffer is configurable, I think it's about 1 Gb,
depends on how long you want to pause the stream and the bandwidth
used by the channel.

The powerdown of the HDD does work well, although the 2-3 second spin
up time is not very wife friendly, and I'm not too convinced it does
the drive too much good either.

> I'm not currently taking this option seriously. It would be too
> difficult to run a CAT5 cable down from the attic to the ground floor.

Yes getting the cable down the from the roof was a bit traumatic,
especially due to the thunderstorm that was so close it blew up my
broadband router - not the best time to be in the attic feeding a
cable down to the ground!

> I was counting just on buying a very quiet fan.

This is what I've got in the attic, an 8cm fan but only running a few
volts through it rather than the full 12V, even this small amount of
air flow makes alot of difference. Bear in mind the case I'm using
downstairs is one from http://www.hushtechnologies.net/ - so the only
way to get heat out the case is via conduction out of the sides, the
TV cards really suffer.

> Bear in mind I can't really claim to be a
> purist since I have a PS2 (original black version) and they are pretty
> damn loud... until recently, we watched all our DVDs on the PS2.

This is exactly what we used to use, damn that fan is loud!


> Hmm, I don't quite understand what you mean. Are you saying that the MII
> 12000 lacks the horsepower for deinterlace?  Do I need deinterlacing? I
> somehow thought that was only necessary when displaying to a monitor,
> rather than a TV screen, but maybe I'm exposing my ignorance there.

If the original source is interlaced, deinterlacing on a monitor is
essential, even some BBC DVD's are seem to be interlaced.

>
> I think I'm veering back towards the ATX box solution, partly because I
> think it's going to be cheaper, and partly because I think it's going to
> be less hassle.

You're probably right this is how I started, got an old desktop and
had a look at what Myth could do, but then I got hooked, and had to
buy quieter and smaller components!

Good luck with it,

Paul


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