[linux-dvb] Re: dvb-t: multiple cards per box?

Tim Hewett tghewett1 at onetel.com
Tue Jan 3 13:36:15 CET 2006


Stef,

I have two SkyStar 2 PCI cards, a Freecom DVB-T USB2 stick and a
Hauppauge DEC2000-t USB1.2 DVB-T receiver. All work happily
at the same time even with the first three recording an entire
transponder/multiplex each though the hard drive can struggle to
keep up, the Hauppuage can only record one VPID and APID at
one time unfortunately. I think 4 devices is the limit of the driver.

This is all on a 550MHz Pentium PIII, even in the worst case there
is still plenty of CPU to spare.

I also use dvbstream, you cannot capture different PIDs to different
files but if you install libdvb you will get the dvb tools which  
allow you
to separate out the various channels into individual program streams
once recording is complete, for example if multiple_pids.mpg contains
BBC1 (VPID 600, APID 601) and BBC2 (VPID 610, APID 611), and
maybe all the other channels on the BBC DTT multiplex:

ts2ps 600 601 < multiple_pids.mpg > BBC1.mpg
ts2ps 610 611 < multiple_pids.mpg > BBC2.mpg

Obviously this means having a decent amount of hard drive space
available.

I did start working on a utility to fan out/duplicate a DVB stream
containing multiple VPIDs and APIDs to multiple pipes, each being
read by a ts2ps process filtering for particular PIDs. This would
achieve what you are (and I was) looking for, but I never got round
to finishing it - program clashes are rare and if they do happen
then it is easier to use two dvbstreams with one using one device
for one broadcast and another for the other. It would be more
elegant to integrate the ts2ps functionality into dvbstream (to avoid
using lots of pipes and duplication of a high bandwidth DVB stream)
and it probably wouldn't be that hard either if you can find and
factor out the core functionality in ts2ps. Then you could do:

dvbstream .... 600 601 -f BBC1.mpg 610 611 -f BBC2.mpg ....

HTH,

Tim.


On 3 Jan 2006, at 11:00, linux-dvb-request at linuxtv.org wrote:

> I have a nova-t pci which works great under ubuntu on it's own, but  
> I'm
> thinking about putting in an extra card so I can capture more  
> channels.
> I'm guessing the limit is probably the pci bus, rather than  
> anything else.
>
> Has anyone successfully achieved this?
>
>
> Also, is it possible to capture arbitrary collections of PIDs to
> separate files, so that one can capture more than one channel from a
> Transport Stream at once?
>
> I've been using dvbstream to capture a single stream, but don't  
> know how
> to make it split into multiple files.
>
> Happy New Year, and thanks in advance
>
> stef

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