[mythtv-users] Digital Cable.

[Joseph A. Caputo]

On Friday 27 August 2004 12:34, Ejay Hire wrote:
> Hi all.
>
> As I understand it, Digital cable is MPEG2 streams over DOCSIS.  It
> seems kind of silly to decode them, convert them to analog tv, and
> then re-encode them in a capture card.  Is it possible to skip the
> decode/analog/reencode step and suck these in directly?

Well, it's not quite so simple...

Theres a new card out (Dvico Fusion HD3000, IIRC) that is capable of 
decoding QAM (that's the transport (??) that digital cable uses).  The 
first problem is that there are no Linux drivers for it (yet).  
However, the bigger problem is that any over-the-counter hardware 
capable of decoding regular digital cable (QAM) is only going to be 
able to deal with unencrypted content.  A lot of the content from the 
major cable providers is encrypted (not just the premium channels, 
either), requiring vendor-provided hardware (set-top box) to decrypt.

IIRC, the cable industry has been mandated to provide "keys" (CF cards 
or some similar technology) that would plug in to future devices 
(digital cable-ready TVs, etc) to enable the decryption of encrypted 
QAM programming without a set-top box.  Nothing has come to market yet, 
though, and when it does it will be crippled because it will be after 
7/2005 and must therefore honor the Broadcast Flag.

The bottom line is that the industry does not want you to have access to 
the high-quality digital stream, because (a) you must be a thief, and 
(b) if you're not a thief, then they want to be able to make money by 
selling you locked-in, closed, proprietary solutions.

Now, in the satellite arena, there's at least a choice, since the FCC 
has mandated satellite providers to provide an enabled FireWire port on 
their set-top boxes.  So, even though everything coming out of that 
port will be on-the-fly transcoded down to 480p (to comply with the 
Broadcast Flag), at least it will be pure digital.

That's my high-level understanding of things; perhaps someone else can 
explain it better.

-JAC