[mythtv-users] Always something going wrong with Myth

Jim Carter jimc at math.ucla.edu
Mon Dec 22 18:04:57 UTC 2008

On Fri, 19 Dec 2008, jedi wrote:

> On Fri, Dec 19, 2008 at 09:30:13AM -0800, Steve Peters - Priority Electronics wrote:
> > Hello. I just can't seem to get myth to work properly. There's always
> > something that it's messing up on.
> > 
> > Live TV absolutely never has the voice sync working. All recorded shows and
> > all movies work just fine. So I'm stumped on this one.
>     Mebbe you should consider not trying to use the DVR as a TV. Even when
> we still had our Tivos we really didn't do that. We kept around a separate
> tuner for that. If you can't wait until the show ends before you start
> watching it, you're not going to really benefit that much from a DVR. You
> won't be able to skip the commercials much.

We use the DVR system for live TV, and we particularly like "watch-behind", 
i.e. suppose the news starts at 18:00 for an hour; we start watching the 
recording at 18:20 and then use fast-forward to skip commercials.  Auto 
commercial flagging is nice, although not 100% reliable whereupon you have 
to skip back and use fast forward.  But in the "watch-behind" mode 
commercial flagging hasn't been done yet, and fast-forward is just fine.

As for the sound sync, I have a pcHD-5500 TV card, for which (on my kernel) 
you need to connect the provided audio cable to a sound card's line-in.  I 
had to do some fiddling to figure this out: my onboard Intel ICH5 (i8x0) 
sound "card" has a sink mixer to unconditionally mix line-in with 
the outgoing sound, and a separate capture mixer to gate line-in to the 
capture bus.  With the sink mixer on, you hear up-to-the-second TV 
sound, but you're watching delayed recorded video.  Turn on the capture 
mixer, and turn the sink mixer down to zero.  (And make sure that Myth is 
capturing from the actual capture source.)  Then you will record sound in 
sync with the video, and play back what was recorded.  

Instructions will have to be varied according to the card and the sound 
chip.  In particular, I think you mentioned a Hauppauge card, from which 
(If I remember) you can capture as an ALSA source via OSS emulation, 
without the audio cable.  But for me the hard part was figuring out what 
the mixer was trying to accomplish, and working with it, not against it.

James F. Carter          Voice 310 825 2897    FAX 310 206 6673
UCLA-Mathnet;  6115 MSA; 405 Hilgard Ave.; Los Angeles, CA, USA 90095-1555
Email: jimc at math.ucla.edu  http://www.math.ucla.edu/~jimc (q.v. for PGP key)

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