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	qc-usb: Logitech QuickCam USB Video Camera driver
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QUICKSTART
----------
Type "./quickcam.sh" in the current directory and follow the instructions.

Requirements
------------
An USB camera with ST Microelectronics bridge chip and either VV6410,
HDCS-1000, HDCS-1020 or Photobit sensor. Usually Logitech QuickCams qualify,
but check if your camera is supported from http://qce-ga.sourceforge.net.
Important notice: never trust that if camera named "xxxx" is mentioned
as supported, it really is. There are many different cameras sold
with exactly same name/model, with some working and some not. Examples
are QuickCam Notebook and Labtec cameras, of which some work and some don't.
VendorId and ProductId, as reported by lsusb, help much determining
whether a camera really is supported, but even they aren't failproof.
The VendorId should be 0x046D and ProductId one of 0x0840, 0x0850, or
0x0870 or the camera definitely is not supported by this driver.
	Required kernel: Linux 2.2.x (x >= 18), 2.4.x, or 2.6.x.
x86 is best tested, but the driver might also work on other architectures
(I got a success report on Alpha and PPC). SMP appears to work too.

Where to get it?
----------------
Well, you're already reading this so you obviously should already have 
the driver too. But just in case, here's the important links:
	http://qce-ga.sourceforge.net
	http://sourceforge.net/projects/qce-ga
	http://sourceforge.net/project/showfiles.php?group_id=12924
To get the latest version under development, use anonymous CVS
at http://qce-ga.sourceforge.net.
Here may be also some interesting links and information:
	http://www.ee.oulu.fi/~tuukkat/quickcam/quickcam.html

How to install?
---------------
The recommended way is now just to run the script "./quickcam.sh" in
the driver source directory. In some cases you might want to run
make manually, as described in the following:
	Type "make clean && make all" to compile the driver. The
resulting driver file is "quickcam.o" for kernels 2.2.x and 2.4.x,
or "quickcam.ko" for kernel 2.6.x. Type "make" to get some installation
options. Especially you should consider disabling debugging, it will make
the driver about 30% smaller and faster (this is now the default). And if
compressed mode is not supported with your camera, you might want to
compile the driver with "make all USER_OPT=-DCOMPRESS=0", which will 
save some more bytes.
	Note: /lib/modules/x.y.zz/build should be a symbolic link to your
kernel source. It is created automatically by "make modules_install" in
kernel source directory, but some distributions (such as Debian) might not
have it pre-installed correctly. You can make the link manually or by 
specifying alternate kernel source directory with LINUX_DIR=/usr/src/x.y.zz.
You can see the kernel version that you are running with "uname -r".
	The kernel source must be configured (with "make menuconfig", for
example) to have the same options as the kernel you will be running with the
camera. Also "make dep" must be performed in the kernel source directory
before the camera can be compiled against it. One way is to download fresh
kernel source into /usr/src/linux-x.y.zz, copy .config into the directory,
and then enter "make oldconfig && make dep". Then you can compile the
camera driver against the kernel source using the LINUX_DIR option, and
compile the kernel with "make bzImage && make modules", install the
kernel with "make modules_install" and running lilo, and install the camera
driver with "MODULE_DIR=/lib/modules/x.y.zz make install", and reboot.
With kernel 2.6.x you must use "make modules_prepare" instead of "make dep".
You should also compile the kernel and the camera driver with same versions
of gcc. Check gcc version with "gcc -v" and the version which was used
for compiling the kernel with "cat /proc/version".
	Easier is just to install the kernel source package from your Linux
distribution and compile then the camera driver. For example, in Debian
you should first check which "kernel-image" package is installed, and
then install the corresponding "kernel-headers" package, which is
correctly preconfigured (at least on x86).
	The driver is accessed using either /dev/video or /dev/videoX
device file. If you are using devfs, it should appear automatically when
the driver is loaded. If not, you can create the file manually with
	mknod /dev/video0 c 81 0
	mknod /dev/video1 c 81 1
	chmod a+rw /dev/video0
	ln -s /dev/video0 /dev/video
as root.
If you still don't have a clue, ask from 
qce-ga-discussion@lists.sourceforge.net.

How to load?
------------
You need USB and Video4Linux support in your kernel. Check that they
are compiled, if not, reconfigure kernel, compile and install. It took
a long time to find the Video4Linux checkbox in 2.2, it is in 
	Character Devices / Video4Linux
When you have a supported kernel, just load the necessary drivers with
	modprobe videodev
	modprobe usb-uhci	# Either UHCI or OHCI,
	modprobe usb-ohci	# loading the another will fail
	insmod ./quickcam.o(.ko) compatible=3
(or "modprobe quickcam" if you have already installed it).
If it works, you can install these lines into some startup script
in /etc to load the driver every time you boot up your computer.
	If you're using hotplug (package "hotplug" on Debian), the driver
should be loaded automatically (in 2.4.x and newer kernels) when you plug
the camera in (after you have installed the driver with "make install").
For hotplug to work, the UHCI or OHCI driver has to be first loaded,
on Debian typically by inserting the correct driver name into "/etc/modules".

How to run?
-----------
After the driver has been loaded, you can run your favorite camera software 
such as Xawtv, Motv, or Mplayer/Mencoder (see file APPLICATIONS for some
suggestions). If you have multiple video devices, do
	cd /proc/video/quickcam
	ls -la
to see which devices are allocated for the qc-usb driver. You can examine
the contents of the video* files in the above directory by using e.g. "cat".
Specify /dev/video* device file corresponding to the desired camera
to the program what you are using.
	There's an utility called "qcset" that you can use to change
driver options on-the-fly. Run "qcset -h" for more info. It is recommended
that you use qcset to change driver options instead of using module parameters
when loading the module with insmod. The module options might go away in
future, and you can set different options for each plugged camera only with
qcset. Check out the possible module parameters with "qcset -h".
If some piece of program doesn't work, try enabling more compatibility levels:
	qcset compatible=16x,dblbuf
By default all compatibility is disabled, because it is the user applications
not the driver which should be fixed. Meanwhile, use either compatible=1
or 3.
Some programs that require compatible=1: anything using the Xvideo driver.
Some programs that require compatible=3: motion, vic.
	Other available options with qcset:
-b and -c	Set camera exposure time and gain, when automatic adaptation
		is disabled. When enabled, -b selects the target image
		brightness, into which the adaptation algorithm tries to
		settle.
-o and -u	Set camera color balance. If the color strength (-o) is
		less than half of the maximum (the default), all colors
		have the equal gain and hue (-u) has no effect. Otherwise,
		the relative color gains are balanced according to hue
		and color strength. These options have effect only with
		the HDCS and Photobit sensors, and on Photobit only when
		automatic exposure control has been disabled (adaptive=n).
-w		Set image sharpness. This option has effect only when
		image quality is 5 (best). Zero value corresponds
		to quality 3 (bilinear). Also, this option has no effect
		when compression is enabled.
-g v		Enable lookup-table with the given gamma value
-g rg:gg:bg	Specify different gamma value for each channel
-g rg:gg:bg:rw:gw:bw	Specify also color gain for each color channel
		Gamma and color correction is useful if your sensor does
		not support hardware correction with options -o and -u.
		The gamma values should be between 0.5...1.0 and the
		balance weights around 0.7-1.3. You can but probably should
		not use equalization simultaneously with software lookup-table,
		because the advantage is dubious.
		Software lookup table will have no effect when compression is
		enabled (compress=y).
-e filename.pnm	Compute and enable static equalization from given PNM/PPM
		image file. Similar to "equalize=y", except that the
		equalization lookup table is calculated from given image
		file only once, and not constantly. This avoids problems
		with flat surfaces or other views that do not contain
		balanced colors (e.g. if you would point the camera at
		full-red car, equalization would make it not to look red
		at all).
		How to generate own image for equalization:
		- qcset equalize=n quality=bilinear -g -
		- xawtv -noxv -noscale (disabling Xvideo is required)
		- Point the camera into something that contains good balance
		  of all primary colors, red, green, and blue. Something like
		  pale walls are not good, try a bookshelf or something.
		- Run GIMP, select "File/Acquire/Screen Shot".
		  Enable "Single Window", disable "Decorations", click OK.
		- Click on the Xawtv window. If you get completely blue
		  image instead of what xawtv displays, then you didn't
		  disable Xvideo.
		- Click on the GIMP image window with right mouse button,
		  select "File/Save As...", enter filename.pnm, select
		  raw PNM file.
		- qcset quality=best -e filename.pnm
		The equalization image is sensor and lighting-specific, so if
		you change the camera or go indoors/outdoors, redo the
		procedure above.
		There may be some pre-made equalization files in
		http://www.ee.oulu.fi/~tuukkat/quickcam/eq-*.pmn.
		This option can not be use simultaneously with the "-g" option.
		You can disable static equalization with "-g -".
		Software lookup table will have no effect when compression is
		enabled (compress=y).
-g + / -e +	Enable software-based lookup-table for correcting colors
-g - / -e -	Disable lookup-table
-g '?' / -e '?'	Display whether lookup-table is enabled and the table contents
qcdebug		Enable selected debug messages. You can write symbolic list
		of error message types or bitmask, for example
		"qcdebug=errors,common" displays debug messages related to
		various errors and some common messages as "frame lost".
		The kernel messages are logged typically into file
		/var/log/kern.log.
		Note that if the driver was not compiled with debugging
		enabled ("USER_OPT=-DDEBUG") this option will not do much.
debug		Same as 'qcdebug', for compatibility with older versions.
keepsettings	Keep image settings over camera uses. When this option
		is disabled, the image settings (brightness etc.)
		are reset to the default values each time when a program
		opens the camera.
settle		Specify the maximum number of frames to wait for image
		brightness to settle before starting capturing. Has
		effect only when adaptation is enabled. For example,
		if settle=30, the camera driver waits maximum of 30
		frames until automatic adaptation (brightness control)
		has stabilized the image brightness and only then gives
		the first image. Some programs, e.g. xawtv, don't like
		if the driver pauses for a long time.
		This option is particularly useful if you take single
		image snapshots but the images are too dark or bright.
subsample	Increases framerate but decreases image resolution.
		May work or not to work depending on camera sensor type.
		Works on HDCS-1000. To get high frame rate, you must use
		short exposure time. Either disable adaptation and set
		contrast into small value or use enough light so that the
		adaptation routine uses short exposure time.
compress	Enable MJPEG compression with QuickCam Web and LEGO cameras.
		On other cameras, compression is automatically disabled.
		When using compression, image size is fixed to 320*240
		and frame rate is about doubled to 15 frames per second.
frameskip	Lower frame rate by skipping frames. Decreases CPU
		power requirement. For slow computers.
quality		Select image conversion routine which is used for
		converting Bayer CFA image into RGB image. Has no
		effect when compression is enabled.
adaptive	Enable or disable automatic brightness control.
		Use -b to set the target brightness.
equalize	Equalizes the image. May improve colors hugely sometimes.
userlut		Enables or disables the default whether to use software
		lookup-table color correction in the driver. Affects only
		cameras which are plugged in after setting this setting.
		For already plugged-in cameras, use -g and -e options.
retryerrors	If there are problems with communicating with the camera,
		and retryerrors is enabled, the driver tries to retry
		a few times instead of immediately failing and returning
		error to application.
compatible	Enable various compatibility levels:
		16x: force image width and height be multiple of sixteen.
		dblbuf: lie applications about the number of frame buffers.
		torgb: convert BGR values into RGB.
video_nr	Select the video device number to use. Can not be set
		with qcset.
You can query the named parameters by adding a question mark, for example
	qcset 'qcdebug?'
displays the current debugging selection.
With kernel 2.6.x you can run qcset simultaneously while running other
applications which use the camera. With older kernels, you must close
other applications before qcset can be used.

Controls
--------
There are two ways to control the camera brightness, hue, etc.: either
using the automatic brightness control that changes the camera exposure time
and gain constantly, trying to match the values which is set into the
"brightness" setting. In this mode the "contrast" setting has no effect.
Another option is to disable automatic brightness control, and set it
manually instead. In this case "brightness" controls the exposure time
and "contrast" controls the global gain with VV6410 and Photobit sensors,
with HDCS-1000/1020 the controls are swapped. If "saturation" is more than 
32768, the "hue" setting will balance gains between red, green, and blue 
gains. Note that with VV6410 it is not possible to set different gains to
different primary colors, so with it the "hue" and "saturation" have no
effect.
	Photobit and HDCS sensor give the faster framerate, the smaller window
you use. VV6410 has constant framerate, independent of window size.
Reducing the window size will make field of view smaller.
With all cameras you can enable subsampling mode, which will give higher
framerate at full view of width (but gives no more resolution than simply
using smaller window size).
	Too big exposure time may slow down the frame rate. So you might
actually get better framerate at bright light, when the exposure time is kept 
short.

Reporting bugs
--------------
Please report about bugs to qce-ga-devel@lists.sourceforge.net. The
SourceForge has a bug tracking system, but unfortunately I don't follow
it much. The bug report should include:
- Camera name (e.g. QuickCam Express)
- Sensor type (load the driver and type "dmesg" right after or look
  from kernel log files, typically at /var/log/kern.log)
  (e.g. HDCS-1020)
- Camera ProductId and VendorId, or just run "lsusb" and copy all what
  it shows to the report. (lsusb is in package "usbutils" in Debian).
- Exact error messages and what applications you tried to use.
  If you get compile errors, compile e.g. with
	make all 2>&1 | tee errors.log
  This will save the errors in file errors.log.
- Kernel version and gcc version (use "cat /proc/version" and "gcc -v").
- cat /proc/video/quickcam/*
- Anything else you think could be useful.
If you have any problems, try running the script "quickcam.sh". It
will determine automatically system configuration and check many
possible problems.
	You can enable debugging mode in the driver by compiling
it with
	make clean; make all USER_OPT="-DDEBUG"
After this you can set a suitable debug level with qcset, for example
	qcset qcdebug=errors,common
and the driver will print lots of debugging messages to the kernel
log files.

The Story so Far
----------------
"Georg Acher had pulled the first picture out of the QuickCam Express. He 
posted a note on the qvix site with a link to his work saying that he didn't 
have time to do a V4L driver. I posted a note on a few LUGs and started a
project being far outclassed by Jean-Frederic Clere, who within 48 hours had 
made the first V4L driver and has been the rock that supported QuickCam 
Express. ... qce-ga was a project code, not actually a name: quickcam.sf.net 
had been taken by the QuickCam Pro. " (edited from Peter McConnell's mail)
(See README.qce about the qce-ga driver)
	Cristiano De Michele modified the qce-ga driver to support Logitech 
QuickCam Web. Unfortunately, his drivers had some problems: the drivers didn't
support compressed mode, without which the frame rate would be only 7.5 frames 
per second. 
	But then Jochen Hoenicke did something extraordinary: he reverse
engineered the compressed image format. Unfortunately, his hacked drivers were 
not Video4Linux compatible, so they couldn't be used by any standard Linux
video application.
	I (Tuukka Toivonen) took the qce-ga driver code and modified it a LOT.
There's still much original code left, but also many routines have been
completely rewritten or added. Thanks to Jochen Hoenicke, there's now
support for compressed mode with (only) VV6410 sensor. Unfortunately,
it didn't work very well for a long time.
	But then Cristiano stroke again: he supplied a patch that showed
where the problem was. And now this driver, finally, has very usable support
for the compressed mode with the QuickCam Web. Hopefully other cameras
will follow, althought this is yet uncertain.
	I want to give special thanks to Peter McConnell, who started the
project originally and did excellent work maintaining mailing lists and
project web pages, until he disappeared.
				Tuukka Toivonen <tuukkat@ee.oulu.fi>