Webcam tips

[tempestuous]

Back in Feb 2009 I posted a dotpet package of the libv4l library, which is a "helper" library for some of the less common webcam drivers, such as the sn9c20x (microdia) module.
At that time, the standard Puppy kernel version was 2.6.25.16.

Since then Puppy has moved up to the 2.6.30.5 kernel, and there seems to be an increasing number of webcam problems reported.
I suspect this may be due to a fundamental change to webcam drivers since kernel version 2.6.27,
and it seems that many, if not all, webcam drivers now require the libv4l library.
For the history of this situation, refer to this article by the developer of libv4l -
http://hansdegoede.livejournal.com/6317.html

So webcam tip number 1 is to install and use the libv4l library, from this forum post:
"Extra drivers for Puppy 4.1 with 2.6.25.16 kernel"
http://www.murga-linux.com/puppy/viewto ... 689#270689
Carefully follow the instructions in that post.

Now there are various applications which will display and/or record your webcam image:
- gxine (which I dislike and distrust)
- mplayer - but only versions which are configured for v4l/v4l2 support, such as this one
http://www.murga-linux.com/puppy/viewtopic.php?t=26511
- xawtv
http://www.murga-linux.com/puppy/viewtopic.php?t=19918
- skype
- uvcview ?

The next problem is that most of these applications will try to output their video image in "Xvideo overlay" (xv) output mode, which is good,
because this output scheme takes advantage of the hardware-accelerated features of your Xorg graphics driver ...
but unfortunately this output method will fail with many webcams, because the webcam driver fails to create an xv-compatible output.

There are 2 workarounds for this situation, and 1 true solution. Your mileage may vary.

Workaround i) if you are using Xorg (which generally, you should) then you can force the viewer application to use the non-accelerated "x11" video output method.

Workaround ii) you could run the Xorg wizard and revert back to Xvesa display.

or true solution - install the v4l Xorg extension plugin, which I provided here -
http://www.murga-linux.com/puppy/viewto ... 407#271407
Note that you must configure this plugin by modifying your xorg.conf file, as explained in that post.
And obviously you must restart X, or reboot.