[mythtv-users] DCH-6416 Firewire capture

Brad DerManouelian bderman at gmail.com
Thu Jun 11 21:53:08 UTC 2009

On Jun 11, 2009, at 2:27 PM, Robert McNamara wrote:

> Hi Brad,
> Good to see you posting.

Thanks, Robert. After spending a week on this, I figured someone here  
had run into it already and would have an immediate answer. Stuff in  
my personal life has settled down a bit so I have some time to help  
out on the list again.

> 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.

Very helpful! I got firewire_tester to work with those options and  
installed the crontab at 5 and 35 minutes past the hour for one box  
and 7 and 37 past the hour for the other. I'm excited to stop using my  
HD-PVR boxes and simplify my setup a while bunch.

Thanks again,


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