[mythtv-users] firewire with 3250

Eric Smith erictsmith at gmail.com
Fri Nov 17 17:12:09 UTC 2006

Just thinking out loud here....  I to have a 3250HD box with firewire
working fairly reliablly as long as i stay within the non 5c channels.
 However, I'm also feeding an s-video stream from the same cable box
for channels which are not available over the firewire connection.  So
quite frequently i will hit one of those channels that the firewire
connection can not recover from.  Typically when i see this i just
unplug the firewire from the cable box for a few seconds, plug it back
in and everything is up and running again.  Unfortunately, this is not
good for the WAF when I'm not around to notice and Grey's Anatomy
records as an empty file.

So my thought is, there are several versions of scripts out there now
that can be used to "prime" the firewire connection and make sure it
is available.  I haven't used them myself yet, but assuming they are
not too resource/time consuming... would it be possible to set it up
to always check the connection and rerun one of these types of scripts
before changing the channel to something on the firewire input?

And a follow-up (perhaps wish-list thought).  Is there a way (or could
there be) to associate an HD channel to its equivalent non hd channel.
 So in the example above, myth starts the recording of Grey's Anatomy
on the HD channel.... immediately recognizes that the firewire
connection is not available and switches the recording the the non HD

Like i said... just thinking out loud.

On 11/3/06, Scott Alfter <mythtv at salfter.dyndns.org> wrote:
> nik gibson wrote:
> > I'm pulling content over firewire off a 3250HD box.  All the modules
> > load find, plugreport looks good and my first 2 or 3 test-mpeg2 streams
> > work perfectly.  Then after the 2 or 3 successful streams all the sudden
> > I get nothing, the command test-mpeg2 -r 0 > testcap.ts just returns an
> > empty command.  I'm forced to reboot and then it works a couple time
> > until breaking again.
> Mine runs for a few days (or maybe more), then it starts recording empty files.
>  Resetting the FireWire bus gets things working again for a few more days.
> Here's the script I use, which saves the bother of rebooting the machine:
> #!/bin/sh
> size=0
> while [ $size -eq 0 ]
> do
>   echo Resetting FireWire bus...
>   modprobe raw1394
>   modprobe ohci1394
>   /usr/local/bin/sa3250ch 105
>   sleep 1
>   rmmod raw1394 ohci1394 ieee1394
>   modprobe raw1394
>   sleep 5
>   modprobe ohci1394
>   sleep 5
>   ( test-mpeg2 -r 0 foo.mpg 2>&1 >/dev/null & sleep 10 && pkill test-mpeg2)
>   size=`du foo.mpg | awk '{print $1}'`
>   rm foo.mpg
>   sleep 2
> done
> echo Reset complete.
> This script gets run at boot time before mythbackend, and is run manually
> whenever I notice screwed-up recordings.  It puts the cable box on a known
> digital channel, unloads and reloads the FireWire modules, makes a quick test
> recording, and verifies that there's actually something in the recording.
> I should probably get an HDHomeRun and use that, but this'll get me by in the
> meantime.
>   _/_
>  / v \ Scott Alfter (remove the obvious to send mail)
> (IIGS( http://alfter.us/            Top-posting!
>  \_^_/ rm -rf /bin/laden            >What's the most annoying thing on Usenet?
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