awalls at radix
Jul 17, 2009, 5:49 PM
On Fri, 2009-07-17 at 19:16 -0400, Andy Walls wrote:
Re: Fwd: [UNKNOWN IVTV CARD] (cx23416) AverMedia M113-C
[In reply to]
> On Sat, 2009-07-18 at 02:35 +0530, Ravi A wrote:
> > On Tue, Jul 14, 2009 at 6:07 AM, Andy Walls<awalls [at] radix> wrote:
> > It so happens the driver/utility is setting the input back to Y0
> > (default, white connector) whenever video format is changed -
> > $sudo v4l2-ctl -s pal
> > sets MUX input to Y0 from wherever it was. However -
> > $sudo v4l2-ctl --log-status
> > still shows the input to be Line-In!
> > $sudo v4l2-ctl -i1
> > $sudo v4l2-ctl -i2
> > sets the input back to Y1 and sound re-appears.
> > Is this how the behavior should be?
> Nope. Good observation, this is the bug. I checked the source code of
> ivtv-gpio.c and the version history, and it's a bug that's been in the
> ivtv driver since before it was in the mainline kernel.
> It should be striaght-forward to fix the behavior, but I'll have to take
> a look and make sure there's not some odd board that needs something
> special. I'll have a patch ready soon.
I have pushed a patch to
The bug was ancient. It looks like it arose from an old method of
setting the tuner back to TV when exiting from FM radio mode. It had
the side effect of changing the audio input of a GPIO audio mux back to
the tuner whenever the video standard was changed when you were not in
Apparently no one with a card with a GPIO audio mux ever changed the
standard when set to Composite or SVideo.
> > When MUX is set properly and sound is present, the volume was still a
> > bit low and it seemed very noisy - something like zero-crossing
> > distortion. I could improve it a bit by setting volume all the way
> > high.
> > sudo v4l2-ctl -c volume=65535
> > Setting bass and treble to '0' helped to reduce the distortion/noise
> > significantly although the volume still seemed low
> > sudo v4l2-ctl -c bass=0
> > sudo v4l2-ctl -c treble=0
> > If I can get v4l2-dbg to read/set registers maybe I can try more
> > experiments for the audio quality.
Yes, it will give you the flexibility to experiment will all sorts of
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