Tivo vs MythTV

Ben Scott dragonhawk at gmail.com
Wed Nov 8 20:35:09 EST 2006


On 11/8/06, Thomas Charron <twaffle at gmail.com> wrote:
>   Comcast does randomize their frequency usage, which is a big nono for them
> to do, but they do it apperently.

  I'm *shocked* to hear that.  ;-)

>   Bear in mind, this is for NON ENCRYPTED HD signals.  Some channels
> transmitted in HD will more then likely be encrypted ...

  s/some/most/.  From what I understand, almost all of them *are*
encrypted.  Same idea as with the "scrambled" channels and decoders
boxes in days gone by.  Except that the encryption is apparently a lot
better these days.  It used to be that everyone and their brother was
selling kits to crack the analog scrambling.  I haven't seen that with
the high def, digital systems.  I never touched that stuff
(seriously!), but I knew people who did.  :-)

  I had forgotten that channels broadcast OTA in the local area are
also sent unencrypted over the cable networks.  I believe that's by
FCC rule.

> ... which you'd need a special card to be able to tune in, which I believe
> Comcast will sell to you ...

  Right, a "CableCARD".  The FCC forced the cable operators to make
something available that would let us dumb ole "consumers" tune in
digital cable on something *other* than a cable company decoder box.
Newer digital TVs all have CableCARD slots in them for this purpose.
The Series 3 TiVo has two slots (dual tuners).

  From what I understand, it works like this:

  A CableCARD is a PCMCIA Type II card.  You buy or rent them from the
cable operator.  The host device (TV, TiVo, etc.) tunes in the digital
signal off the wire.  The host feeds the bitstream to the CableCARD,
which decrypts it and feeds the cleartext signal back to the host.
The CableCARD has a mechanism to talk to the overmind at the cable
company, and figure out which channels you get (HBO, etc.).

  The card also has a mechanism to verify that the host has been
certified by Cable Labs (a cable industry tech group) to respect all
their copy restriction stuff.  In other words, that the host device
won't let you make unrestricted copies of the signal, any digital
output is also restricted (HDCP), etc.

For the following:
  MRV = Multi-Room Viewing = coping recordings from one TiVo to another via LAN
  TTG = Tivo To Go = copying recordings off TiVo onto a PC for playback there

  That's why the TiVo Series 3 doesn't support TTG or MRV yet.  Cable
Labs doesn't have any policies in place for certifying the TiVo box's
copy restriction stuff.  Supposedly, TiVo Inc is trying to work this
out with them.  I suspect they'll probably get there *eventually*,
just because the cable industry doesn't want this to escalate to
another government battle they could loose, but I'm sure they'll drag
it out as long as possible, too.

  Another practical upshot of all that is that you'll never see a
Linux PC that you can plug a CableCARD into.  I suspect you'll never
even be able to do it on 'doze.  The cable operators want things
locked up tight.

> ... but it may be hard to get in touch with the right person to buy one.

  Yah, apparently most of the front-line drones in the cable companies
are pretty clueless about thus stuff right now.  (Another shocker.)
It varies a lot from region to region, too.  Apparently Comcast in NE
doesn't do too bad (at least compared to some other operators).  But
they still insist that the cards be "installed" by one of their field
drones, which means you have to wait for a "truck roll" (dispatch to
your home) so they can plug the card into your TV for you.

> Unfortionatly for me, sat companies dont sell these beasts.

  Yah, satellite isn't subject to the same regulations as cable, so
the government is largely hands-off.  The satellite operators use
different technologies, and consider CableCARD and things like it a
threat to defend against.

-- Ben


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