I agree that there seems to be more than one variation
of this audio problem and not sure if they are
related.

I tried some more experiments and was able to generate
a few variations of the bad audio (May account for why
some people have different results).  I will try to
post some more mpegs to my site this weekend.  
I noticed that the cx25840 module is setting register
0x808 to 0xf6 which is a semi automated (standard =
BTSC, mode = auto detect).  I modified cx25840-core.c
to try different values for this register:

For 0x808 = 0xf6 (the default):  soft reset can
occasionally toggle the problem on and off.  Since the
mode is auto detected, I checked the detected mode in
register 0x804.  When audio is bad, it says 0x11
(Stereo+SAP).  When audio is good, it says 0x01
(Stereo only).  Also, the bad audio is generally much
louder than the good audio.

For 0x808 = 0x14 (force BTSC, mode=stereo):  I tried
this thinking that if the only problem is when SAP is
active, then forcing it to stereo without SAP would
fix it, but not true.  I can still toggle problem on
and off.  However, when audio is the the "bad" state,
it is much louder and noisier than when I used
0x808=0xf6.  

For 0x808 = 0x10 (force BTSC, mode=mono):  I can still
toggle bad audio on and off.  But this is yet another
variation of the bad audio.  Now it sounds very quiet.
 It sounds like when you hook up speakers wrong and
their phases cancel each other out.

There are probably some other combinations I could
try,  but so far it seems like the audio standard/mode
detection is not responsible for this problem, because
no matter what I set, I still have the problem.

I really don't know anything about BTSC other than
what I'm reading in the cx25840 manual.  It talks
about combining the L+R and L-R signals.  Maybe the
problem is in how that happens.  At one point it
really did sound like L-R coming out.

I'll get some more mpegs up this weekend.

Jim


--- John Biundo <[EMAIL PROTECTED]> wrote:

> Moasat wrote:
> 
> > Mine does not sound exactly like that.  Yours
> sounds like the actual volume
> > changes a bit as well.  My volume mostly stays the
> same and I don't have any
> > whine in the audio.  But I think I can here the
> same tinny sound behind the
> > whine in your clip.  Here are two of my samples:
> > 
> > http://www.quicksfv.org/tinny1.avi
> > http://www.quicksfv.org/tinny2.avi
> > 
> 
> This definitely sounds like a different kind of
> audio distortion than 
> what I'm getting.  Mine is much more similar to
> Jim's at 
> http://www.geocities.com/high_alive/
> 
> Seems like there may be two related problems here.
> 
> It might be useful to get more samples and/or more
> people who have what 
> they think is "tinny audio" to compare these clips.
> 
> _______________________________________________
> ivtv-devel mailing list
> [email protected]
> http://ivtvdriver.org/mailman/listinfo/ivtv-devel
> 



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