[AG-DEV] Additional Grabber settings

[Douglas Kosovic]

Hi Todd,

> > Does your webcam driver take a gamma and gain kernel module argument?
> > If so, it can be set in /etc/modprobe.conf.
> 
> Unfortunately it doesn't appear as though the Logitech QuickCam Pro
> 4000  has that option on module load.  The only options modinfo lists are:
> 
> parm:           size:Initial image size. One of sqcif, qsif, qcif, sif,
> cif, vga (charp)
> parm:           fps:Initial frames per second. Varies with model,
> useful range 5-30 (int)
> parm:           fbufs:Number of internal frame buffers to reserve (int)
> parm:           mbufs:Number of external (mmap()ed) image buffers (int)
> parm:           trace:For debugging purposes
> parm:           power_save:Turn power save feature in camera on or off
> (int)
> parm:           compression:Preferred compression quality. Range 0
> (uncompressed) to 3 (high compression) (int)
> parm:           leds:LED on,off time in milliseconds (array of int)
> parm:           dev_hint:Device node hints (array of charp)
> 
> 
> I've also tried setpwc after the module loads but it doesn't have a
> gamma setting and vic seems to reset any gain settings I make.

I'll have to think about and research it some more, unlike many of the other
V4L2 controls which have a range of 0 to 255, the gamma control varies with
V4L2 drivers, e.g. PWC is 0 to 32, Ricoh is 0 to 500, many are 0 to 255 and
some are -128 to 128 and I'm not 100% certain yet it is possible to
programmatically determine what the max and min values are for gamma.

I'm worried that providing a gamma slider control in the Video &
VideoProducer services might not cover the range that the V4L2 driver
supports making some of the V4L2 only webcam drivers too dark or too light
and not being able to adjust.

I'll also look into why the PWC driver doesn't remember it's settings
between restarts of vic.


Cheers,
Doug