[vdr] Re: complicated hardware setup

[Rene Bartsch <ml@bartschnet.de>]

Am Die, 2003-05-13 um 02.24 schrieb Oliver Brandt:

> > Should use 1000Base-T for the server (one TS-stream from the server has
> > about 25-40 MBit/s).
> 
> This means I'll need a 1000Base-T switch, too. I looked at alternate and
> they are very expensive (300 Euro). I belive there are others avalible
> with just one 1000Base-T port but I could not find any and so I don't
> know how expensive they are.

Much cheaper. You can also look at ebay. Currently you often get 6 or 12
month old high-end switches for low prices because of the much
insolvencies in Germany.

> Anyway, talking about 1000Base-T the
> PCI-bus poped into my head. Is a 32bit PCI engought for the 1000Base-T,
> one Nexus, three Novas and the IDE-Raid. Seams to me this could be the
> next problem (German: Flaschenhals). Do you think I need a 64bit PCI?
> Because then we are talking serious money, The 64bit Mainboard, 64bit
> 1000Base-T and switch, 64bit IDE-controler (could not find one on alternate)... Do
> you think 64bit is necessary?
> Would a complete set of Nova cards instead of the Nexus make any
> difference on the server cpu and bus load?
> How fast of a cpu do I need in the server and how much Ram?

I'm maintaining a server with 3 budgets, DVD-R(W), one HDD and
1000Base-T running NFS, NIS, DNS, vdr-streamdev and Firewall.

It's a simple 32-bit system with Celeron1100, 768 MB RAM.

If I remind well PCI has a throughput of about 800 MBit/s.
Running 4 DVB-S recording will consume about 120 MBit/s, the 1000Base-T
NIC (all have cache and own µProcessor) will consume less than 240
MBit/s.

Onboard Raid-controllers are good for nothing. You'll only scare the PCI
when you invest at least 500 Euros in an IDE-Raid controller.

> 
> > 
> > You'd need an active cooled CPU.
> You mean without the dxr3?

5 lines below is the answer. ;o)

> > There's no support for MPEG2-HW-decoding in linux for that boards and no
> > soft-based A/V-backende for linux. So you need to take a DXR3. It
> > provides Composite, S-Video, analogue stereo, and PCM/AC3-SPDIF.
> > 
> > And you can use a weak, passive cooled CPU.
> 
> What does the cluster-plugin do? Does it translate the viedo-input into
> mpeg1 or mpeg2 or something compleately different to send it over the
> network?

The A/V (e.g. DivX) is sent from the client to the server, which
transcodes into MPEG1 and sends back the stream.

> By using a dxr3 I understand those weak clients won't need the
> cluster-plugin for playing the DVB-stream delivered by the
> streaming-plugin and for DVDs. Do I need it for playing divX or can
> I go totally without the cluster-plugin in case of a
> dxr3.

You need something like a Celeron500 (maybe 400 MHz could work) to
transcode from DivX to MPEG1. The passive cooled VIAs are to weak to do
this. Then you need the cluster-plugin.

> In this case only the DVB-stream (mpeg2)

Yes.

 and compressed DivX-movies stored on the server

If your Client is active cooled and fast enough to do realtime
DivX2MPEG1-transcoding.

> will be sent over the network and never more then one way, so one client
> should not need more then 10Mbits of network traffic and a 100Mbit
> infrastructure is enought.

If streamdev (client/server-streaming) uses MPEG-PES, yes. But this
limits usage (No teletext, ...) as you only get the A/V-Pids.

If you call the complete TS so that your VDR-clients works as he has his
own DVB-card you have to calculate with 25 - 40 MBit/s and client.


Rene



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