[mythtv-users] My experience with dual HDTV cable boxes and FireWire

[Steven Adeff]

On 5/12/06, Yeechang Lee <ylee at pobox.com> wrote:
> * In my experience using contrib/channel-changers/6200ch as the
>   channel-changing script in mythtv-setup does not, contrary to Steve
>   Adeff (who does not have two HDTV cable boxes)'s messages, help in
>   the reliability of the FireWire capture process per se. It *does*

I never said it would help in the firewire captures.

>   seem to help a bit with the accuracy of the channel-changing process
>   itself, but I still get a missed change every 30 captures

thats all it will help in, and I never said it would be perfect, only
that the alternate method available may work better. For me and a few
others it does. I happen to be lucky in that the alternate method has
never failed me under normal operating conditions. If i run it by hand
in testing it fails at about the same rate as you show.

>   +-10. Also, contrary to Steve's claims, in my experience the '-s'
>   switch for 6200ch does not help accuracy either; it significantly
>   worsened it. (See

this will depend on the box, your not the only person to say the new
method doesn't work for them, and thats fine, use what works best.

> * I have the following script as /usr/local/bin/firewireset:
>
>     #!/bin/sh
>
>     # This script assumes that two FireWire connections are on
>     # Nodes 0 and 3, both are set to 200Mbps, Node 0 is set to
>     # Broadcast, and Node 3 is set to Point-to-Point.
>
>     plugctl -n 0 oPCR[0].data_rate=2
>     plugctl -n 0 oPCR[0].n_p2p_connections=0
>     plugctl -n 0 oPCR[0].bcast_channel=63
>     plugctl -n 0 oPCR[0].bcast_connection=1
>
>     plugctl -n 3 oPCR[0].data_rate=2
>     plugctl -n 3 oPCR[0].n_p2p_connections=1
>     plugctl -n 3 oPCR[0].bcast_channel=0
>     plugctl -n 3 oPCR[0].bcast_connection=0
>
> After my frontend/backend PC reboots, if the dreaded 'Firewire: No
> Input in 15 seconds' message appears in mythbackend.log, I run the
> script (again contrary to Steve's advice). The odd thing is that
> sometimes it takes two or even three executions before the FireWire
> pump is primed, so to speak. But once a connection happens, subsequent
> connections are 100% reliable (at least until the next reboot).

here's the thing, Myth sets the values you give it in mythtv-setup
before it captures, so I don't see how this will help. I think what
your seeing is still the random chance. Set the firewire settings in
mythtv-setup to what you have in your script and I'll be the success
rate will be the same.


> Caveat: I added the script and much of the above advice to the
> FireWire entry at wiki.mythtv.org several months ago, but most of the
> text has been removed since in favor of a daisy-chain method for
> connecting multiple cable boxes to a single FireWire PC port. I have
> not used this method, but doing so might very well indeed obviate the
> need for the above script, and obviously would also work for those
> with more than two cable boxes or only one FireWire PC port. That
> said, I can say that the above steps definitely, positively, 100% work
> for me, and that's what counts, right?

-- 
Steve
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