[mythtv] AC3 passthrough

Jason Hoos jhoos at thwack.net
Tue Dec 2 12:28:30 EST 2003

> You're not seeing "Audio buffer overflow" messages or anything like  
> that, are you?  I was having problems with OSS sound when I 
> would watch [...]

I got them occasionally, but not as frequently as the dropouts seemed to be
occuring.  I have actually been playing with increasing the audio buffer
size in audiooutputalsa.cpp by adding a secondary buffer to stash more audio
samples outside the soundcard, but it didn't seem to be helping any, and
I've since lost that code. 

> It could also be that your ABC station's MPEG stream has the  audio as  
> relatively large packets, relatively far apart.  More overall  buffering  
> (time delay) would help with that.

Entirely possible.  I was working on putting in some debugging output to see
how often audio packets were arriving, by putting some output in the
AddSamples method or somewhere thereabouts.  I remember it seeming a bit
inconsistent, but I hadn't gotten to the point yet where I could correlate
the timings with the dropouts, never mind figuring out whether the
inconsistency is inherent in the stream or being introduced someplace else.
I'm going to keep playing and see what happens, especially since it does
seem to have something to do with this particular station.  

For what it's worth this is all on an Athlon 3000, using XvMC for video on a
GeForce MX card, so I'm pretty sure that there's no lack of CPU cycles. :)
Anyhow I'm going to keep playing with it and see if I can get to the bottom
of things.  


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