[mythtv-users] DCH-6416 Firewire capture

Robert McNamara robert.mcnamara at gmail.com
Thu Jun 11 21:27:00 UTC 2009


On Thu, Jun 11, 2009 at 2:09 PM, Brad DerManouelian <bderman at gmail.com>wrote:
>
>
> The firewire_tester and priming scripts don't seem to work with this box
> since they were written for the 6200 boxes. I basically need help priming
> the DCH-6416 boxes for consistent firewire capture.
>
> Some additional info:
>
> $ sudo plugreport
> Host Adapter 0
> ==============
>
> Node 0 GUID 0x0023a2fffe12916a
> ------------------------------
> oMPR n_plugs=1, data_rate=2, bcast_channel=63
> oPCR[0] online=1, bcast_connection=0, n_p2p_connections=1
>        channel=1, data_rate=2, overhead_id=0, payload=376
> iMPR n_plugs=0, data_rate=2
>
> Node 1 GUID 0x0023a2fffe12912a
> ------------------------------
> oMPR n_plugs=1, data_rate=2, bcast_channel=63
> oPCR[0] online=1, bcast_connection=0, n_p2p_connections=1
>        channel=2, data_rate=2, overhead_id=0, payload=376
> iMPR n_plugs=0, data_rate=2
>
>
Hi Brad,

Good to see you posting.  The firewire_tester program should work fine with
your box, it may just take some combination of options to get a good prime.
 I use the 3200 and 3216 (exactly the same as your box minus the analog
tuner), and personally use the firewire_primer.pl script from trunk
(mythtv/contrib/user_jobs/firewire_primer.pl) to prime the connection at 5
and 35 after the hour.  It's a helpful script because it leverages
firewire_tester to do the priming, but only does so after checking with the
backend and confirming that the tuner is not in use, which prevents killing
a recording by priming while trying to record.

First thing you need to do is get the box onto a channel that is almost
definitely not 5C.  NBC, ABC, CBS, Fox, etc. are good choices.  Now you
should test the firewire_tester with a variety of options.  The ones that
work best for me are (and here I'll use the example of your node 0):

firewire_tester -n 0 -B -r 5

That's the "Broadcast Stabilization" mode.  The other options besides -B are
-b and -p.  I also use -r 5 to repeat the prime five full times.  Sometimes
if it's particularly tricky to get a good prime, the repeats are enough to
get a good one.  I have found that the plugctl voodoo from the firewire page
on the wiki is useless and has never had any effect. If you are getting
"Failed," that means there's no prime.  If you get "(sync failed)", that
generally means the channel is 5C'd.  Try another channel and see if it gets
any better.

Once you've figured out the options that work for you, I would get the
firewire_primer.pl script from trunk and cron it to run sometime after the
normal program boundaries (5 and 35 after, for me).  For me, I changed the
firewire_tester line to:

my $results = `$firewire_tester -B -P $guid_list{$guid}{host} -n
$guid_list{$guid}{node} -r 5`;

I also tend to run that script manually 10 or 15 seconds after I bring up
the backend just to be sure.  One other thing I needed to do was disable
firewire bus resets in mythtv-setup.  This might help you too.

I hope this help you.  I have not had a failed recording on firewire in a
really long time, aside from the occasional program on a normally reliable
channel that randomly has 5C turned on.

Robert
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