[mythtv-users] DVB-S multirec: how many recordings per card?

Andre mythtv-list at dinkum.org.uk
Thu Dec 9 14:49:37 UTC 2010

On 9 Dec 2010, at 08:06, Stefan G. Weichinger wrote:

> Am 2010-12-09 04:16, schrieb Nick Rout:
>> I have 4 per card, 2 cards a total of 8 tuners. I am on Optus D1
>> http://www.lyngsat.com/optusd1.html and there are only 2 muxes I use
>> (the freeview ones). My system is not a speed demon, no raid, cheapest
>> motherboard i could buy when the old box fell over. It copes, although
>> it rarely records more than 4 programmes simultaneously (except
>> perhaps during overlaps?)
> As I mentioned I still don't really know about muxes ... many things to
> learn with mythtv and satellites ...

When digital satellite TV came along (called DVBS or the newer version DVBS2) it was possible to have more than one television channel on each frequency channel. Before 1 frequency= 1 channel, now 1 frequency=1mux (short for multiplex) and each mux can have several channels.

One tuner (one TV card) can tune to one frequency at a time, (1 mux) usually the card is told to pick out only one of the TV channels in the mux. Multirec is a mythtv feature that allows several of the TV channels to be picked out at once.

Of course the broadcasters don't often put all the channels you want in one mux so it's not always obvious which channels can be recorded at the same time by multirec.

Sites like lyngsat or kingofsat are a way to find out which channels are in which muxes on which frequencies.

> I run with a value of 4 now as well for some weeks (since I upgraded to
> 0.24, I think). It works so far, yes.

4 is a common setting, enough to be useful but not so many that the PC cannot cope with the work. Unless the card cannot work with multirec you always want at least 2 as that allows recording overlaps from the same channel, 4 allows overlaps of four shows in one mux.


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