[mythtv] mythtv-dev Digest, Vol 56, Issue 20

Joe Borne joe.borne at gmail.com
Thu Oct 18 14:29:44 UTC 2007

> Kelly Campbell wrote:
> > Encrypted 5C channels is one problem, but it's a pain to even get the
> > non-encrypted channels to work consistently. I'm not sure this is
> > actually a problem with the motorola's or if it's a linux driver/libs
> > issue. I've never tried capturing on MacOS or windows.
> >
> > I've been able to get my firewire working mostly consistently by
> > building from svn for myth, libraw1394, libiec61883, and libavc1394.
> > They recently made a new release of libraw1394 which included a
> > segfault bugfix.
> >
> > For me this is what I've found is required to get a stable connection:
> >
> > 1. The motorola box has to be powered off (power cable unplugged,
> > firewire is still live even if the) and then plugged back in with the
> > linux system online and firewire connected.
> >
> > 2. I have to run firewire_tester -B -n <node> until it's stable.
> >
> > 3. configure mythtv to connect in broadcast mode.
> >
> > Once in a while it will lose stability for some reason, and just
> > running firewire_tester -B -n once or twice will usually fix it. If
> > not I have to reset the stb power.
> >
> > Hope that helps.
> >
> > -Kelly
> >
> > On 10/17/07, Steven Adeff <adeffs.mythtv at gmail.com> wrote:
> >
> >> On 10/17/07, Joe Borne <joe.borne at gmail.com> wrote:
> >>
> >>> I have a very cooperative cable company (Insight) who is willing to
> help
> >>> resolve the issues some users have with tuning in HD channels on the
> >>> Motorola set top boxes. They feel that I should be able to watch every
> >>> channel I pay for out of the firewire ports on the back, unencrypted.
> They
> >>> would like to work with us as testers.
> >>>
> >>> Who is currently working on the code used to communicate with these
> Motorola
> >>> STBs? I'd like to get them involved so we can work this out. I'm
> running the
> >>> current SVN.
> >>>
> >> all they have to do is turn off 5C in the Motorola software. Normally
> >> this signal is sent by the cable company in the channel/show's digital
> >> stream to the cablebox and is passed through from the network but it
> >> can be intercepted/changed/ignored at any step along that process.
> >>
> >> --
> >> Steve
> >> Before you ask, read the FAQ!
> >> http://www.mythtv.org/wiki/index.php/Frequently_Asked_Questions
> >> then search the Wiki, and this list,
> >> http://www.gossamer-threads.com/lists/mythtv/
> >> Mailinglist etiquette -
> >> http://www.mythtv.org/wiki/index.php/Mailing_List_etiquette
> >> _______________________________________________
> >> mythtv-dev mailing list
> >> mythtv-dev at mythtv.org
> >> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-dev
> >>
> >>
> > _______________________________________________
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> >
> if you're paying for the channels why would they be 5C encrypted on the
> firewire port?

The problem I am seeing is the same as Kelly is indicating. I have several
channels that will not tune in despite  NOT being 5C encrypted. I have
checked them by doing the following:

1. Powering off the STB with the power button while tuned to the channel
that refuses to work.
2. Hitting "setup" on the front of the STB within 2 seconds of power off.
3. Checking the setup screen that appears for the "5C" or "%C" flag. (I
don't remember the exact line, but it was pretty obvious to me.)

I came across a thread in a silicondust forum via google that discussed a
similar problem for folks using a digital tuner card on QAM channels. They
reported almost 100% success if they unchecked a checkbox for "unencrypted
channels only" under the mythtv backend setup >> 4. Input connections menu.


Apparently, some channels can carry a 5C flag even if not encrypted and Myth
picks up on this and doesn't even try to tune them. I did wonder if this
could be a similar issue, but that seems illogical as the STB does change to
the channel but the signal never locks. Unless the two are unrelated, and
what's happening is that the STB changes channels, but then Myth never
really attempts to lock on the signal. I don't know enough about the
firewire connection to even speculate. (Are channels transmitted through the
firewire on different frequencies, or are they all just raw MPEG2 feeds of
whatever channel the STB is on?)

I'm going to attempt Kelly's solution and compile libraw1394, libiec61883,
and libavc1394 from source.

I'll post the results.


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