..... This "live input" can be a TV signal "imported" through a TV-in Card, and I would have hoped it could also be a TV signal "imported" through a DVB-S2 card.
The inherent limit of this sofware is that it accepts only "raw video", posing a potential problem with usage with DVB-S2 cards (if these cards transform incoming signal into something else than raw video).....
With regards to the DVB-S2 card, I am not sure as to what to expect. With the TV-in cards, we've had no problem at all, they were very quiet on resources. My guess at this stage is that if we gear up the hardware for the Flash Media Live Encoder. This should also cover the DVB-S2 card. But we will see.
I don't understand at all what you're trying to do, or how your software works, however I sense a bit of mis-communication in what I see above.
Most DVB-S or DVB-S2 cards don't transform the signal into any kind of video at all. That is usually up to the software that you run. The card doesn't even know if it IS video or if it's some other kind of data. Some of the cards are not even intended to be used for video. Also, whether the card is DVB or DVB-S2, or a digital TV card doesn't really matter much with respect to the video signals that your computer will see from it, it is only important relative to the card's ability to lock onto the sat signal.
There are programs that will grab the video on the sat signal, and make it available to programs via streaming, or by other methods. However sat signals are not in any standard format, and to extract video from the card, your program would not only have to be capable of receiving video from the card, but would also have to be able to communicate with the card to specify which PIDs the audio and video are being carried , and what frequency and SR and FEC and other values that the sat signal is using.
It is not very CPU intensive to have multiple cards on a computer, I have 2 DVB-S cards and a DVB-S2 card, and used to have a TV card, and could use them all at the same time, however displaying video on the computer IS CPU intensive, particularly if it's HD. If you're streaming SD A/V data through the network and not trying to display it on the computer with the cards, then the 2.4 GHz computer should be fast enough for several cards, and there are programs you can buy that will allow you to address multiple cards of the same type via their MAC addresses. I use different model cards, so I didn't need this feature, and I can grab data from all the cards.
I don't have a clue relative to what format your program needs the video to be in, or what they mean by "raw video",. It may be some type of transport stream or program stream. If it is, then I'm guessing that you can probably use something like TSREADER , or a TSREADER/VLC combination to stream to it, but it's also possible that by raw video, they might be referring to an old analog NTSC signal, in which case, DVB-S or DVB-S2 cards won't be of use.
The fact that you're limiting yourself to using one specific program I think limits you somewhat, and perhaps you should be asking your questions at a forum devoted to that software, rather than in a forum with people who don't use your software. Once you find out what format it needs it's data, and/or what cards it's compatable with, then the people here can be of more help I think.