[linux-dvb] What DVB card to buy (was AW: Re: AW: an easy question...)

["Torsten Schlabach" <tschlabach@gmx.net>]

Got it!

Well, of course the DVB card will be the right device to get the DVB
feed (no matter if it comes from satellite, cable or terrestic) into the
server to start with.

You will somehow need to do the MPEG-2 to MPEG-4 conversion in real
time. The DVB card will not at all help you and I don't know if there is
any hardware that can do that for you. If you want to do it in software
you'll need a really fast PC, but my guess would be that the latest
systems in the range of 2-3 GHz might be able to handle this. Maybe
anyone has any experience here. Also you might want to think of SMP, but
be sure that software you're using will support it.

Talking about WHAT card to buy:

1) Satellite, Cable and Terrestic are separate cards that are usually
marked DVB-S, DVB-C or DVB-T. I don't know of any card that can handle
more than one signal source or where the physical tuner modules was
pluggable.

2) You'll notice that there are hughe price differences between cards.
The range goes all the way from 48 EUR to about 300 EUR. I am not sure
if you have the details on why that is, but for the benefit of anyone
later maybe reading the mailing list archive, let me elaborate a bit on
this.

There are two categories of cards: The so called "full featured" and the
"budget" cards. "Full features" stars at about 250 EUR whereas budget
cards cost about half the price.

The full featured cards have an on-board hardware MEPG-2 decoder built
in and usually have a separate composite or S-video connector that is
entirely independent of the PCs VGA card. You can think of a
full-featured card pretty much as a digital sat receiver put on a PCI
extension card. You can use the PC only for switching channels if you
want to but these cards are also able to overlay the decoded video
stream onto your VGA screen, so using the onboard video output if not a
must but an option. Nevertheless even if you use your VGA screen for
watching TV, the card does the MPEG-2 decoding for you leaving the CPU
of the PC pretty much alone.

The "budget" cards don't have any of this. All they do for you is tuning
a DVB channel and making the encoded raw data steam available the PC on
the PCI bus. They leave it to software and the PC's CPU to decode and
display the MPEG-2 stream if you want to. (If you just want to record or
stream the MPEG-2 stream you don't have to decode it, so there is no
point in paying for a decoder you don't need.)

In practice when it comes to budget cards at least in Germany (and
probably in other markets) you'll have a choice between two designs: The
TechnoTrend designed cards that market mostly under the brand name of
Hauppauge (WinTV NOVA) and sell for about 100 EUR or the TechniSat
SkyStar 2 card that sells for about 50 EUR or even less.

To make a long story short: They are pretty much equal when it comes to
functionality (except there is not CI option for the SkyStar 2) but the
SkyStar 2 is (not yet) supported under Linux which limits it's usability
there. (The card is more than fine if you are using Windows and don't
need any CI. Note: It also does not yet work with any Windows SoftCI,
but I guess this is not the place to get deeper into that aspect of
DVB.)

The reason why it is not supported is that it uses a different chipset
than the TechnoTrend cards. The chipset on the SkyStar 2 is by B2C2 and
nobody has written a Linux DVB driver for it yet for whatever reasons
that don't belong here. The card is cheaper because the B2C2 chip is
cheaper than the one TechnoTrend uses.

There IS a Linux driver for the SkyStar 2 but I am not sure about its
status. You'll sometimes find it as a binary only download on some
Russian sites, but there is no evidence that it comes from either B2C2
or TechniSat or that they support it at all. It's for sure that it is
not Open Source, there is no source code available for it and it does
not conform to the proposed (or maybe even in the meanwhile official)
Linux-DVB API. So even if you find this driver and make it work without
any support you will no be able to run apps such as VDR or dvbstream or
the like with it.

In short words: If I was you I'd buy a budget TechnoTrend compatible
card with or without CI (depending on weather you need it).

Hope this helps. Maybe this might become a Mini-HOWTO?

Torsten

-----Ursprüngliche Nachricht-----
Von: linux-dvb-bounce@linuxtv.org [mailto:linux-dvb-bounce@linuxtv.org]
Im Auftrag von Alexis Guerin
Gesendet: Mittwoch, 5. Februar 2003 12:40
An: linux-dvb@linuxtv.org
Betreff: [linux-dvb] Re: AW: an easy question...

Sorry, I just read my message again and it was indeed not very clear.
I want to have the DVB card in a server to receive MPEG-2 streams from
the 
sattelite and then stream them in MPEG-4 format on o LAN.

Alexis

On Wednesday 05 February 2003 11:19, Torsten Schlabach wrote:
> Dear Alexis,
>
> I don't quite get from your message what you are going to stream where
> and if you are thinking of having the card in the server or in the
> client.
>
> Do you already have MPEG-4 content that you plan to stream and want to
> use the card as a hardware-decoder? Or do you plan to receive any
MPEG-4
> streams from the satellite and then stream them over an IP network?
>
> Torsten
>
> -----Ursprüngliche Nachricht-----
> Von: linux-dvb-bounce@linuxtv.org
[mailto:linux-dvb-bounce@linuxtv.org]
> Im Auftrag von Alexis Guerin
> Gesendet: Dienstag, 4. Februar 2003 13:01
> An: linux-dvb@linuxtv.org
> Betreff: [linux-dvb] an easy question...
>
> Hi all,
>
> I'm not familiar with dvb, and I actually don't have a dvb card yet.
> But I was wondering if it there is an easy way to use a common card
like
> the
> Hauppauge DVB-S card with the DVB , to stream mpeg 4 with mpeg4ip and
> the
> Darwin Streaming Server.
>
> Any comment will be very helpful!
>
> Alexis



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