Re: libv4l release: 0.5.97: the whitebalance release!

[Adam Baker <linux@baker-net.org.uk>]

On Wednesday 15 Apr 2009, Hans de Goede wrote:
> Currently only whitebalancing is enabled and only on Pixarts (pac) webcams
> (which benefit tremendously from this). To test this with other webcams
> (after instaling this release) do:
>
> export LIBV4LCONTROL_CONTROLS=15
> LD_PRELOAD=/usr/lib/libv4l/v4l2convert.so v4l2ucp&
>

Strangely while those instructions give me a whitebalance control for the 
sq905 based camera I can't get it to appear for a pac207 based camera 
regardless of whether LIBV4LCONTROL_CONTROLS is set.

> Notice the whitebalance and normalize checkboxes in v4l2ucp,
> as well as low and high limits for normalize.
>
> Now start your favorite webcam viewing app and play around with the
> 2 checkboxes. Note normalize seems to be useless in most cases. If
> whitebalancing makes a *strongly noticable* difference for your webcam
> please mail me info about your cam (the usb id), then I can add it to
> the list of cams which will have the whitebalancing algorithm (and the v4l2
> control to enable/disable it) enabled by default.

The whitebalance works really well with the sq905 (ID 2770:9120). Without it 
the image is very red when using artificial light, with auto whitebalance the 
colours look slightly desaturated but otherwise fine.

Adam