[mythtv-users] Digital Cable newbie questions
mythtv at rodsbooks.com
Wed Apr 11 19:48:58 UTC 2007
On Wednesday 11 April 2007 11:28, Douglas Hitchcock wrote:
> Until now I've used only analog cable, to make my life simple. Now Comcast
> is forcing digital on me, and I'm kind of annoyed.
> They tell me they're giving me a DCT 700 converter box, and I have no other
> choice. Does anyone use a DCT 700 successfully and happily?
> I have dual tuners, a pvr250 and a pvr350, and a normal 4:3 tv.
> So I guess I need two converter boxes?
Maybe, maybe not. If you can find out how much of the digital content you want
is encrypted, you'll be better able to decide how to proceed. Assuming you
don't want to upgrade to HD, there are three approaches, but which will work
best depends on how your cable company delivers the signal:
1) Use the cable company's STB with its output fed into your existing tuners
and IR blasters (or possibly some other method) to control the STB. This
will enable you to record anything that the STB outputs, but the signal
will go from analog (at the source) to digital to analog (out the STB) to
digital again, which will surely degrade it compared to a simpler path.
IR blasters are also less than 100% reliable, although they can sometimes
get pretty close to 100%.
2) Use the cable company's STB with Firewire output into the MythTV box.
This can provide a simpler path (with one less digital-to-analog
conversion), but if I understand correctly, most cable companies encrypt
most digital content, and the Firewire output is useful only for
unencrypted channels. If you go this route, you'll be able to ditch
your existing tuner cards, unless you want them for something else
(direct OTA recording, say). You may need to specifically request an
STB with Firewire output. My understanding is that cable companies
are required to offer these, but my knowledge of this area is a bit
3) Turn down the cable company's STB and instead buy one or more digital
tuners. These are often sold as HD tuners, but they should be able to
record SD digital content. They'll be useless for recording encrypted
digital content, though. The HDHomerun (an external Ethernet device)
and AVerMedia AVerTVHD A180 (a PCI card) are often cited as good digital
tuners. I've got one of the latter and it's fine, although I can only
tune a couple of stations in the clear from my cable company (Cox in
If the stations you want to record are being sent in the clear, then I'd say
#2 or #3 would be better, since you'll get a cleaner recording; however, most
cable companies encrypt some or all of their digital offerings, so #1 may be
a necessity. It could also be that you'd need to record in HD to get some of
the stations you want if you go with #2 or #3. This would require either more
disk space and CPU power or a delay while you transcode the HD content down
to something your system can play back. If you've got the CPU power and disk
space, though, MythTV can play back HD content on an SD (NTSC) set.
Of course, you can mix and match. For instance, if your cable company sends
locals in the clear but other stations in encrypted form, and if a lot of
what you record is locals, you could use one digital tuner card along with
the STB and one of your existing analog cards.
> I think that's it, thanks for indulging a digital cable newbie. I've
> searched and read but, I am still confused, I've been willfully ignorant of
> these things until now and am trying to decide if I'm ready to learn, or
> switch cable companies :)
Murphy's Law says that if you switch, the new company will go all-digital
within a few months.... :-\
You could also consider satellite; however, both DirecTV and Dish Network are
all-digital, and essentially only option #1 works. (There are hacked
receivers with Firewire output, but I know little about them except that
they're ridiculously expensive and targeted to HD users.)
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