[mythtv-users] Firewire Issues...

[Michael Tiller]

So I ordered Comcast digital cable.  When I was ordering I asked them
whether the STB would come with Firewire ports.  They said "yes, but they
are disabled".  I figured that was probably typical but I'd complain about
it once I got the box (wasn't expecting really use them anyway).

Well, it turns out they aren't disabled.  In addition, some quick
experimenting with my XP laptop and I was capturing video nicely through
Firewire.  I figured a few more tweaks and I'd have it integrated into
MythTV.  Well, almost. :-)  So I'm looking for any assistance.

First, the strange part...I naturally assumed that the only channels I would
be able to get (at least in HD) would be broadcast channels.  Well, it turns
out that HD Theater is also available through my Firewire port (and
unencrypted QAM too).  So I wondered what else.  I went to A&EHD and I could
record that with my XP laptop.  So I went to the diagnostic screen on my
Motorola 3412 (Cable-Power-Select) and checked the port status (d11) and
sure enough it very clearly said "5C=0 - Copy Free". I thought that was
pretty cool so I started poking around.  I went to TNTHD and did the same
thing.  That was also listed as "5C=0 - Copy Free".  Even HBOHD said this.
Wow, I thought.

Well, this is odd because what I have noticed is that when I try to record
from HBOHD or TNTHD, it doesn't work.  My guess is that this is a 5C
encryption issue but I'm not really sure.  If something is 5C'd, can you
still grab the video (just not watch it)?  Or does the encryption interfere
with the "grab".  (I'm using dvgrab 3.0 with the -f hdv option, BTW)

Assuming that 5C prevents dvgrab from working then it appears that the cable
box very clearly says 5C=0, but that there is, in fact, some kind of 5C?!?
I double checked the tuner channel and the 5C settings several times in the
diagnostic screens.

Now, I wanted to try and figure out what channels were available via
Firewire so I started doing a "firewire_tester -b -n 0" on various
channels.  Some seem to work consistently while others don't.  So I made
sure to do a "firewire_tester -B -n 0" before actually trying to grab
packets (this is all in a script, no manual).  That helped, but things were
still a bit inconsistent.  So I currently do the following:

6200ch $CHL
firewire_tester -R
firewire_tester -B -n 0
firewire_tester -b -n 0 -r 5

(then I check the return status of the last command)

It still doesn't give me a reliable result about what can be acquired via
Firewire and what can't.  Would "priming" help in this case (i.e. doing a
grab as well)?  My feeling is that if "firewire_tester -b" doesn't work,
there is really no point in attempting a grab...but what do I know.

Now for my last question and this is with regards to managing the tuner with
MythTV.  Channel changing works fine so right now I'm just grabbing the
S-video output from the 3412 and recording it with a PVR-150.  It doesn't
give me HD video for anything, but at least I can record every channel the
box provides.  If I go with Firewire as the "preferred input" then I could
get at least some of the HD channels to my Myth box.  BUT, if Myth tries to
simultaneously record one show via the PVR-150 input and another through
Firewire, there is really only one tuner between them so it won't work.  Is
there some way to tell Myth that it has to use either the Firewire or the
PVR-150 but not both?

On a related note, I need to setup two different channel lineups in
SchedulesDirect corresponding to the same provider but with different
channels available.  I'm assuming there is a way to do this, but there are
any tricks related to this I'd be happy to hear them.

Thanks for any guidance and assistance on any of this.  I'm hoping to be
able to use the Firewire port to get HD off of channels that I would
otherwise not be able to record in HD. :-)

--
Mike
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