[mythtv-users] DVB / deinterlacing setup

John Sturgeon john at sturgeonfamily.com
Mon Jun 21 13:59:21 EDT 2004

Hello Flemming.

I'm going to make a big leap here and answer your questions based on my 
HDTV setup (very similar to DVB).

Flemming Frandsen wrote:

> Hi, I'm about to invest in a large DVB setup and I'd like to describe it
> and hear if my plans are realistic at all.
> I have a rather long way from my antenna/dish to my hometheater / other
> viewing locations so I want to put all tuners in a pc placed near the
> antenna.
> I want 3 DVB-s tuners (budget cards) that each output a TS and a PVR 250
> card in that box.
> Q1) Does mythtv support simply storing the demuxed mpeg stream from the
> TS and PVR on disk?

Nope.  MythTV leaves the MPEG-TS stream intact.  You can use ProjectX to 
demux it.

> Q2) ... so I'm right in assuming that the tunerbox (aka mythtv backend)
> doesn't need that much CPU when all it does is shovel data from the tuner
> to the network card?

That is correct, but depending on how much data three DVB streams would 
write, you might want to consider disk I/O a possible bottleneck.

> I have several places I want to watch TV and I don't want disks making
> noise in any of those locations, so I want a separate server and boot
> all other boxes (including the tuner box) of that one via the network.
> One front end is going to run on an x-box, I assume that's working.
> For the other front ends I want to build some small EPIA-M boxes that
> contain a DVD drive and an mpeg hardware decoder.
> * One of them is going to use the tv-out port and analog onboard sound.
> * The other will output VGA to my CRT projector, preferably scaled up
> (1024x768) at a higher refreshrate (100/120Hz) and deinterlaced.
> Q3) How well supported is deinterlacing?
> Q4) Will digital sound from DVB pass through the system unmolested?

yes (with alsa)

> Q5) Is it possible for two backends to share one DVB card?
> (multible channels can be multiplexed into one TS)
> Q6) Is it possible for two backends to share one PVR250 card? (I will
> receive 1 (one) analog channel, so there is no reason to ever change 
> that channel, but I have at least 3 different frontends, where more 
> than one might want to watch the analog channel at once)
> Q7) Is it possible to place a DVD drive on another machine than the 
> front end?

nfs is your friend.

That's about all I have, I hope other folks can fill in the rest for you.

Good luck,

John Sturgeon <><

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