[mythtv-users] HDTV, Myth, HD-2000, HD-3000, questions galore (and hopefully answers from the smart people... )

[Julian]

Hi,

Can someone explain then what the hopes for recording
encrypted HD "digital cable" content with the HD-3000
or a similar device?  I know there are smart cards and
the like, which TiVo intends to support, but what hope
is there that MythTv will be able to support such
schemes?  For me, and prob. others, this is the root
of the newbie's concern when brewing and investing
into a PVR.

Thanks,
Julian

--- Cory Papenfuss <papenfuss at juneau.me.vt.edu> wrote:

> On Tue, 18 Jan 2005, Cook, Garry wrote:
> 
> > I've been watching this thread with interest, but
> have a question
> > regarding statements referring to "over cable".
> Are we speaking about
> > digital cable, or analog?
> > Forgive me if QAM or some other acronym should
> easily answer my
> > question. I'm not yet familiar with all of the
> terms.
> >
>  	There are a number of subtle issues going on here.
>  The basic 
> thing is that a pcHDTV-[23]000 is essentially a
> one-way modem (I guess 
> that's just the dem then... :).  All it does is
> receive an analog signal 
> and decode its modulation.  The digital-to-analog
> modulation scheme for 
> over-the-air HDTV in the US is 8-VSB, which the
> pcHDTV-[23]000 cards 
> currently support.  The modulation scheme typically
> used for cable tv 
> systems' "digital cable" is a different type, called
> QAM.  Since it's 
> essentially just reprogramming how to interpret the 
> downconvertered/sampled data, it's essentially a
> firmware upgrade 
> (assuming computational power isn't an issue). 
> Thus, it's possible to 
> receive "digital cable" with nothing more than the
> 1-way modem provided by 
> the pcHDTV-[23]000.
> 
>  	That said, many/most digital cable system encrypt
> the signal.  So, 
> while the QAM demodulator can receive the bitstream,
> it's encrypted and 
> cannot be played without decrypting it.
> 
> Hope that helps,
> -Cory
> 
>
*************************************************************************
> * Cory Papenfuss							*
> * Electrical Engineering candidate Ph.D. graduate
> student               *
> * Virginia Polytechnic Institute and State
> University 			*
>
*************************************************************************
> 
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