[mythtv-users] Firewire fleeting on SA3250HD

[John P Poet]

On 7/24/06, Allan Wilson <allanwilson at gmail.com> wrote:
> On 7/22/06, John P Poet <jppoet at gmail.com> wrote:
>
> >
>  I have been struggling to get *reliable" firewire communication
> between my computer and my SA3250HD cable box.  I got it working last
> night, and scheduled a half dozen shows to record on different
> channels, throughout the night.  They all recorded just beautifully.
>
> Today I noticed a recording start up, and the SA3250HD trying to
> change channels but it went to the wrong one.  I stopped the recording
> and changed the channel myself.  Then I tried to capture via
> test-mpeg2 but got a zero length file.  After about 30 minutes of
> randomly trying things, I got the firewire to work again.... for a
> while.  A few hours later it was out of sync, again.
>
> If I use 1394commander to reset the bus, and use plugctl to prime the
> bus, and get the channel changed to a good one, and use test-mpeg2, I
> can get eventually get a valid video stream.  Once test-mpeg2 is
> working, I can start myth backup and it will work -- for a while.
>
> I have not been able to figure out the sequence of events needed to
> get the 1394 bus resynchronized when it looses it.  Sometimes just
> resetting the bus is enough.  Other times it seems like various
> combinations of plugctl and test-mpeg2 are necessary.
>
> I get the impression that people with Motorola boxes have a bit more
> success with this, than those of us with Scientific Atlanta boxes.
>
> The very first time I ever successfully captured video via firewire,
> It was after I followed Allan's directions here:
>
> http://www.gossamer-threads.com/lists/mythtv/users/209409#209409
>
> Unfortunately, those instructions do not work every time.
>
> Since I cannot remember where I got it, I am attaching the version of
> sa3250ch.c that works (most of the time) for me.
>
> John
>
>
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>
>
> Just an idea but could you be changing to an encrypted channel that causes
> you to loose your connection to the cable box. I had to create a new listing
> and tie that listing to my firewire tuner so that firewire would only pickup
> recording and change to channels it could get to. Just an idea
>
> Allan


Yeah, I did the new lineup from the beginning.  Only channels above
100 show up via the firewire.

For kicks I tried tuning HBO and grabbing data via test-mpeg2, but got
a zero byte file.  As soon as I switched to a "valid" channel,
test-mpeg2 was able to grab data again.

I still do not have a reliable recipe to get data via the firewire.

I do seem to need to get the firewire synchronized *after* starting
mythbackend.  If I have it working, *then* start mythbackend, it
looses the sync.  So, I start mythbackend, then proceed to beat on it
with various techniques until test-mpeg2 produces some data -- at that
point myth will work fine until I restart mythbackend or try to use
live tv.

John