On 26 Sep 2001, Gerd Knorr wrote:
> Stephen Davies wrote:
> >
> > Hi Gerd,
> >
> > If you call VIDIOCSAUDIO with a volume > 65535 on my msp3400-equipped
> > board then "bad stuff" happens:
>
> How do you do that? video_audio.volume is __u16, you can hardly put
> anything > 65535 in there ...
/me digs deeper
Ah. Then:
If volume has been set to 0 then VIDIOCGAUDIO returns balance 0.
The application I'm having trouble with uses VIDIOCGAUDIO to fetch the
audio settings, resets the volume and calls VIDIOCSAUDIO. Result is that
the balance gets "stuck" over to the one side.
It's got to do with this code in msp3400.c for VIDIOCGAUDIO:
va->volume=MAX(msp->left,msp->right); // =0
va->balance=(32768*MIN(msp->left,msp->right))/
(va->volume ? va->volume : 1); // =0
va->balance=(msp->left<msp->right)?
(65535-va->balance) : va->balance; // =0
I suppose the best fix is to remember the balance as set - but an OK fix
could be just to insert:
va->volume=MAX(msp->left,msp->right); // =0
if (va->volume == 0)
va->balance = 32768;
else {
va->balance=(32768*MIN(msp->left,msp->right)) /
(va->volume ? va->volume : 1); // =32768
va->balance=(msp->left<msp->right)?
(65535-va->balance) : va->balance; // =32768
}
Probably there's a better way to tweak it but I'm tired and this works for
me!
Secondary question: how can you set this balance in xawtv? No control
shows up for balance on my system, and you can't set the left and right
separately.
Steve
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