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Using your webcam with full resolution under Mandriva (2007.0)

This article indicates how to use Luc Saillard’s pwc implementation

Saturday 4 November 2006

This procedure has been succesfully applied for webcam Logitech Quickcam Pro 4000 and Philips Toucam II PCVC840K Pro.

History

The pwc driver was very popular at handling most Philips-based webcams (this includes some Logitech and some Creatvie Labs webcams).

To get the best of you webcam, you had to compile a GPL part (pwc) and a binary decompressor (pwcx) provided by Nemosoft.

In 2004, the kernel hook provided by the GPL part of the driver was considered harmful. This lead to the disruption of the driver from Nemosoft (see http://marc.theaimsgroup.com/?l=linux-kernel&m=109374032407528&w=2).

Two weeks later, Luc Saillard provided a patch to get a complete pwc driver, made of the GPL part + a reverse-engineered code of the pwcx (see http://marc.theaimsgroup.com/?l=git-commits-head&m=111024238821857&w=2).

It was incorporated into vanilla kernels 2.6.12 and 2.6.13 but Nemosoft stated the reverse-engineered part was in fact decompilated and could not be included as is in the vanilla kernel for legal reasons.

That’s why since 2.6.14, the free driver pwc actually available in the vanilla kernel (available at http://www.kernel.org) offers actually at most a QCIF resolution (176*144).

Fortunately, you can still get the full driver, maintained and developped by Luc Saillard from his web page.

We’ll see below how to install it easily using PLF’s sources.

For detailed informations on the driver’s history, you could have a further look at:

http://www.uwsg.iu.edu/hypermail/linux/kernel/0408.3/1394.html
http://marc.theaimsgroup.com/?l=mandrake-expert&m=109363640824582&w=2

Installation

Add the Contrib sources (use http://easyurpmi.zarb.org to get an easy process), and in a console as root, do:

urpmi dkms-pwc

This will replace the pwd driver included in Mandriva’s kernel (limited to QCIF resolution) by Luc Saillard’s enhanced one.

To use the new driver, remove the old one from memory and insert the new one (be sure to have all programs using your webcam closed):

rmmod pwc
modprobe pwc
(a reboot will do the same)

You should now be able to get full resolutions from you webcam, provided you use the CCD resolution and not the extrapolated one indicated on the webcam’s box. For example, most 1.3 megapixel webcam are in fact able to provide a 640*480 image which is interpolated to 1280*760. The driver provides you only the 640*480 image, not the interpolated one.

You can test your resulting setup with Camstream (urpmi camstream, available in the contrib section). This programs allows to easily change your webcam’s resolution, to do snapshots, etc.

Working webcams

http://www.lavrsen.dk/twiki/bin/view/PWC/WorkingWebcamsWithPWC

Webcam drivers sites

http://www.saillard.org/linux/pwc/
http://linux-uvc.berlios.de/ (for newer webcams)
Old Nemosoft driver

6 Forum posts

  • dkms-pwc on plf ? 12 November 2006 at 09:53, by Hervé

    Thank you for this article : the status with these WebCams was not clear, now I better understand.

    I tried to install dkms-pwc, but urpmi didn’t find it on plf.

    I was able to see with camstream QCIF, but not better resolution...

    Could you precise where I can find the right dkms-pwc, please ?

    Reply to this message

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