[mythtv-users] firewire with 3250

[John P Poet]

On 11/17/06, Eric Smith <erictsmith at gmail.com> wrote:
> 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
> equivalent.
>
> Like i said... just thinking out loud.

I have something like this setup for myself.

I use Jim Westfall firewire_tester app within my channel changing
program to make sure I am getting good data.  If the firewire_tester
does not report a good video stream, then my program tries to change
the channel again, followed by another run of firewire_tester, this
time with the -R option, which resets the firewire bus.

For me, the above means that my channel changes are now 100% reliable,
instead of 97%.

Only gotcha, is it can take my SA3250HD box up to 5 full seconds to
change the channel.  Until it successfully changes to the new channel,
it will continue to stream data from the previous channel.  This means
that after issue the channel change command,  my program has to wait 5
seconds before it can trust the output from firewire_tester.

John