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Re: [Spca50x-devs] libv4l release: 0.5.97: the whitebalance release!




On 04/16/2009 12:26 AM, Adam Baker wrote:
> 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.
>

Thats weird, there is a small bug in the handling of pac207
cams with usb id 093a:2476 causing libv4l to not automatically
enable whitebalancing (and the control) for cams with that id,
but if you have LIBV4LCONTROL_CONTROLS set (exported!) both
when loading v4l2ucp (you must preload v4l2convert.so!) and
when loading your viewer, then it should work.

>> 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.
>

Good to hear it helps for the sq905 too, is that the only know id for sq905 cams ?

Regards,

Hans

> Adam
>


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