[linux-dvb] Multiple frontends on a single adapter support

Uri Shkolnik urishk at yahoo.com
Thu Sep 11 19:57:36 CEST 2008

--- On Thu, 9/11/08, Andreas Oberritter <obi at linuxtv.org> wrote:

> From: Andreas Oberritter <obi at linuxtv.org>
> Subject: Re: [linux-dvb] Multiple frontends on a single adapter support
> To: 
> Cc: linux-dvb at linuxtv.org
> Date: Thursday, September 11, 2008, 6:16 PM
> Christophe Thommeret wrote:
> > Uri Shkolnik said:
> > "Some of the hardware devices which using our
> chipset have two tuners per 
> > instance, and should expose 1-2 tuners with 0-2 demux
> (TS), since not all DTV 
> > standard are TS based, and when they are (TS based),
> it depends when you are 
> > using two given tuners together (diversity  mode, same
> content) or each one 
> > is used separately (different frequency and
> modulation, different content, 
> > etc.)."
> > 
> > 
> > 
> > So, here are my questions:
> > 
> > @Steven Toth:
> > What do you think of Andreas' suggestion? Do you
> think it could be done that 
> > way for HVR4000 (and 3000?) ?
> > 
> > @Uri Shkolnik:
> > Do you mean that non-TS based standards don't make
> use of multiplexing at all?
> > 
> I guess diversity mode should be transparent to the user,
> so such a
> device would register only one frontend (and thus only one
> demux) per
> set of tuners used in diversity mode.
> While your statements about non-TS based standards make
> sense, those
> standards would require further work to be covered by a
> future API. In
> this special case, however, we're discussing correct
> usage of the
> current (TS based) demux API.
> Regards,
> Andreas

Regarding the diversity mode - Need to be kept flexible, a device can switch mode (between using a given set of tuners as input for single content or use each tuner for different content)

Regarding Non-TS - I must disagree, there are several posts on this ML that contradict your assumptions, and (much) more important, CMMB after two months of service has much bigger deployment than DVB-H, DVB-T2 and DVB-S2 putting together. T-DMB (DAB) also has much bigger audience.

The optimum is to support all DTV standards :-) , but facing the reality, we must set some priority, and I think the priority should be base on the current users number, and the forecast of DTV standards "market share".



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