Logitech Quickcam on Ubuntu Linux

After installing and starting motion with

> apt-get install motion
> /etc/init.d/motion start

I immediately got some first results. But my first feelings of euphoria quickly vanished, when I tried to increase the tiny resolution from 176x144 to 320x240.

Nothing changed and in the /var/log/syslog I found the following result:

motion: [1] Supported palettes:
motion: [1] 0: MJPG (MJPEG)
motion: [1] 1: YUYV (YUV 4:2:2 (YUYV))
motion: [1] Test palette YUYV (320x240)
motion: [1] Adjusting resolution from 320x240 to 176x144.

The logfile shows that Motion is not using the MJPEG palette which would allow much higher resolutions than the YUYV, which has 176x144 at maximum.

After digging around I figured out that Ubuntu packages of Motion are pretty much outdated. The Ubuntu package is of version 3.2.9-7. Here http://www.lavrsen.dk/twiki/bin/view/Motion/WebHome you can find a newer version 3.2.11 of Motion that claims to fix the palette problem above. There is a new config item in /etc/motion/motion.conf that allows to predefine the MJPEG palette:

v4l2_palette 2

So I compiled the new version from source and restarted Motion with the new settings. But this time it stopped working at all. In the logfile I found the following problem:

motion: [1] Supported palettes:
motion: [1] 0: MJPG (MJPEG)
motion: [1] Selected palette MJPG
motion: [1] index_format 2 Test palette MJPG (320x240)
motion: [1] Using palette MJPG (320x240) bytesperlines 0 sizeimage 42666 colorspace 00000008
motion: [1] VIDIOC_G_JPEGCOMP not supported but it should
motion: [1] found control 0x00980900, "Brightness", range 0,255
 ... cut off ...
motion: [1] Resizing pre_capture buffer to 1 items
motion: [1] Started stream webcam server in port 8081
motion: [0] Thread 1 - Watchdog timeout, trying to do a graceful restart
motion: [0] Thread 1 - Watchdog timeout, did NOT restart graceful,killing it!
motion: [0] Calling vid_close() from motion_cleanup
motion: [0] Closing video device /dev/video0
motion: [0] Motion thread 1 restart

After digging again I found out that the actual uvc-driver does not support the VIDIOC_G_JPEGCOMP ioctl request. You can find the details here:

http://www.lavrsen.dk/twiki/bin/view/Motion/UvcvideoMjpegPatch

There is no need to patch Motion itself since the patch is already part of the latest release. But as stated there the uvc patch still did not find its way into the uvc sources, so I had to download and patch the uvc sources on my own.

I downloaded the sources from here and applied the uvc patch from above:

http://linux-uvc.berlios.de/#download

Unfortunately the patch did not compile immediately. I also had to tweak the uvcvideo.h header file in the v4l directory. Since the uvc_set_video_ctrl function was not visible to the uvc_v4l2.c code, I added it to the header file and removed the static modifier in the uvc_video.c file.

int uvc_set_video_ctrl(struct uvc_video_device *video,
        struct uvc_streaming_control *ctrl, int probe);

I'm not a kernel hacker so I don't know if this is a good fix to that problem, but at least on my system it was working.

So finally I had to reload the uvcdriver and v4l modules into the kernel. You need to reload all the modules below. In case that you want to replace the official kernel modules, make sure that you replace all of them. But first check the modules manually by loading them in this order:

> insmod v4l1-compat.ko
> insmod videodev.ko
> insmod v4l2-compat-ioctl32.ko
> insmod uvcvideo.ko

I restarted Motion and you will not believe it, it started streaming at the right resolution.

Thanks to all those who made it possible!

Hope this helps everybody, who are struggeling the same way as I did.
Jörn