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

[Julian]

Brad,

This is where my hopes of capturing the stream after
the set top box started.  Too bad they were dashed. 
Anyway I have read that the cable companies can detect
how much bandwidth you are consuming...so viewing the
content without paying is risky.  Oh well, I guess the
easy answer to capturing encrypted streams is that it
can't be done today.

Julian

--- Brad Templeton <brad+myth at templetons.com> wrote:

> On Tue, Jan 18, 2005 at 09:16:12AM -0800, Julian
> wrote:
> > 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.
> 
> To answer this, and also to expand on the source
> question about analog
> vs. digital cable.
> 
> Analog cable consists of signals modulated into
> channels, with a series
> of carrier frequencies each so many mhz apart, just
> like over the air.
> 
> Most cable companies implement digital cable by
> taking some of these
> frequencies, and instead of putting in an analog
> signal, they put in
> a QAM digital signal (still modulated on a carrier
> in the same band.)
> 
> The digital cable box is able to decode the QAM
> signal.  Due to compression,
> each old analog channel can hold several streams of
> MPEG for
> SDTV.  So one old analog channel now carries I think
> up to 16 different
> SD channels.  Quite efficient.   The analog channels
> are still there,
> and this allows the same wire into the house to
> provide analog and digital
> cable.
> 
> A new TV with a QAM tuner is able to do what the
> digital cable box does,
> decode those QAM channels, demux them and view them.
>   Unlike the digital
> cable box, it can't decrypt the ones that are
> encrypted.   However, the
> cable card interface allows you to insert a card
> into the TV that can
> do the decryption.
> 
> It turns out, at least where I live, but I think
> this is common, that if
> you have analog cable all it means is that you don't
> have a digital cable
> box.   I put a QAM tuner on my analog cable and was
> able to pick up all
> the QAM signals, and watch the unencrypted ones
> (most, but not all local
> OTA stations.)
> 
> As for the hopes of recording the encrypted content?
>   To do that they
> would need to trust your system with the decryption
> keys, which they
> don't want to do.   In theory one could build a box
> with a cablecard
> slot to decrypt but they are unlikely to licence you
> the tech to do that.
> 
> In theory, one could imagine a PVR that records the
> encrypted stream and
> plays it back later unmodified.  However, what I
> have heard is there
> are timestamps in the stream so that the box can
> tell the difference
> between live and delayed, and refuse to decrypt
> delayed.  Perhaps if
> you fool the clock?
> > _______________________________________________
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> 


=====
Live simply so others may simply live. 
 
-Ghandi 
 
Pluralitas non est ponenda sine neccesitate.
"Entities should not be multiplied unneccesarily" 
 
-William of Occam





		
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