[mythtv-users] First Generation Air2PC Card Requires Extended Initialization

William Powers wepprop at sbcglobal.net
Sat Jan 28 16:43:55 UTC 2006

I recently purchased first generation Air2PC cards off eBay.  I knew 
there might be issues, but it seemed like a low-cost way to experiment 
with digital / HD TV and that has proven to be true.  In fact, the first 
card worked extremely well, no issues whatsoever, so I bought a second 
one.  The second card, however, takes much longer to initialize and lock 
up on its startup channel - usually several minutes as compared to less 
than 30 seconds for the first card I bought.  Once initialized, both 
cards work fine.  However, mythbackend gives up after 30 seconds so 
getting them both initialized is a problem.

I found I could fix that problem by editing 'dvbchannel.h' in libmythtv, 
the line that reads:

"bool TuneTransport(dvb_channel_t& channel, bool all=false, int 

Adding an extra zero to the 'timeout' parameter allows the backend to 
wait long enough for my slow card to achieve a lock.  However, I'm 
curious if there is an easier way.  For example, is there some way to 
condition the card(s) prior to starting the backend that would allow 
them to successfully lock up within the default 30 seconds?

Also, change of subject, is there some trick to getting XvMC to actually 
work?  When I first tried to use it on two machines, both with 0.18.1, 
FX5200's and the NVIDIA driver, only the Hardware MPEG checkbox was 
present on the Playback settings page.  On both machines, when that 
checkbox was checked, playback and live TV would both fail with a 
message saying that the frontend was unable to initialize the display.  
After fooling around with the stuff mentioned above, including a 
recompile of 0.18.1, a checkbox to enable OpenGL vsync suddently 
appeared on the same settings page as the XvMC checkbox and now XvMC 
works on that machine.  But I don't know why it started working and I 
haven't been able to duplicate the feat on my other Myth box.


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