Documentation/video4linux/CQcam.txt - linux - Git at Google

 c-qcam - Connectix Color QuickCam video4linux kernel driver

 Copyright (C) 1999  Dave Forrest  <drf5n@virginia.edu>
 		    released under GNU GPL.

 1999-12-08 Dave Forrest, written with kernel version 2.2.12 in mind


 Table of Contents

 1.0 Introduction
 2.0 Compilation, Installation, and Configuration
 3.0 Troubleshooting
 4.0 Future Work / current work arounds
 9.0 Sample Program, v4lgrab
 10.0 Other Information


 1.0 Introduction

   The file ../../drivers/media/video/c-qcam.c is a device driver for
 the Logitech (nee Connectix) parallel port interface color CCD camera.
 This is a fairly inexpensive device for capturing images.  Logitech
 does not currently provide information for developers, but many people
 have engineered several solutions for non-Microsoft use of the Color
 Quickcam.

 1.1 Motivation

   I spent a number of hours trying to get my camera to work, and I
 hope this document saves you some time.  My camera will not work with
 the 2.2.13 kernel as distributed, but with a few patches to the
 module, I was able to grab some frames. See 4.0, Future Work.


 2.0 Compilation, Installation, and Configuration

   The c-qcam depends on parallel port support, video4linux, and the
 Color Quickcam.  It is also nice to have the parallel port readback
 support enabled. I enabled these as modules during the kernel
 configuration.  The appropriate flags are:

     CONFIG_PRINTER       M    for lp.o, parport.o parport_pc.o modules
     CONFIG_PNP_PARPORT   M for autoprobe.o IEEE1284 readback module
     CONFIG_PRINTER_READBACK M for parport_probe.o IEEE1284 readback module
     CONFIG_VIDEO_DEV     M    for videodev.o video4linux module
     CONFIG_VIDEO_CQCAM   M    for c-qcam.o  Color Quickcam module

   With these flags, the kernel should compile and install the modules.
 To record and monitor the compilation, I use:

  (make zlilo ; \
   make modules; \
   make modules_install ;
   depmod -a ) &>log &
  less log  # then a capital 'F' to watch the progress

 But that is my personal preference.

 2.2 Configuration

   The configuration requires module configuration and device
 configuration.  I like kmod or kerneld process with the
 /etc/modprobe.conf file so the modules can automatically load/unload as
 they are used.  The video devices could already exist, be generated
 using MAKEDEV, or need to be created.  The following sections detail
 these procedures.


 2.1 Module Configuration

   Using modules requires a bit of work to install and pass the
 parameters.  Understand that entries in /etc/modprobe.conf of:

    alias parport_lowlevel parport_pc
    options parport_pc io=0x378 irq=none
    alias char-major-81 videodev
    alias char-major-81-0 c-qcam

 will cause the kmod/modprobe to do certain things.  If you are
 using kmod, then a request for a 'char-major-81-0' will cause
 the 'c-qcam' module to load.  If you have other video sources with
 modules, you might want to assign the different minor numbers to
 different modules.

 2.2 Device Configuration

   At this point, we need to ensure that the device files exist.
 Video4linux used the /dev/video* files, and we want to attach the
 Quickcam to one of these.

    ls -lad /dev/video*  # should produce a list of the video devices

 If the video devices do not exist, you can create them with:

   su
   cd /dev
   for ii in 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 ; do
     mknod video$ii c 81 $ii   # char-major-81-[0-16]
     chown root.root video$ii  # owned by root
     chmod 600 video$ii        # read/writable by root only
   done

   Lots of people connect video0 to video and bttv, but you might want
 your c-qcam to mean something more:

    ln -s video0 c-qcam  # make /dev/c-qcam a working file
    ln -s c-qcam video   # make /dev/c-qcam your default video source

   But these are conveniences.  The important part is to make the proper
 special character files with the right major and minor numbers.  All
 of the special device files are listed in ../devices.txt.  If you
 would like the c-qcam readable by non-root users, you will need to
 change the permissions.

 3.0 Troubleshooting

   If the sample program below, v4lgrab, gives you output then
 everything is working.

     v4lgrab | wc # should give you a count of characters

   Otherwise, you have some problem.

   The c-qcam is IEEE1284 compatible, so if you are using the proc file
 system (CONFIG_PROC_FS), the parallel printer support
 (CONFIG_PRINTER), the IEEE 1284 system,(CONFIG_PRINTER_READBACK), you
 should be able to read some identification from your quickcam with

 	 modprobe -v parport
 	 modprobe -v parport_probe
 	 cat /proc/parport/PORTNUMBER/autoprobe
 Returns:
   CLASS:MEDIA;
   MODEL:Color QuickCam 2.0;
   MANUFACTURER:Connectix;

   A good response to this indicates that your color quickcam is alive
 and well.  A common problem is that the current driver does not
 reliably detect a c-qcam, even though one is attached.  In this case,

      modprobe -v c-qcam
 or
      insmod -v c-qcam

   Returns a message saying "Device or resource busy"  Development is
 currently underway, but a workaround is to patch the module to skip
 the detection code and attach to a defined port.  Check the
 video4linux mailing list and archive for more current information.

 3.1 Checklist:

   Can you get an image?
 	    v4lgrab >qcam.ppm ; wc qcam.ppm ; xv qcam.ppm

   Is a working c-qcam connected to the port?
 	    grep ^ /proc/parport/?/autoprobe

   Do the /dev/video* files exist?
 	    ls -lad /dev/video

   Is the c-qcam module loaded?
 	    modprobe -v c-qcam ; lsmod

   Does the camera work with alternate programs? cqcam, etc?


 4.0 Future Work / current workarounds

   It is hoped that this section will soon become obsolete, but if it
 isn't, you might try patching the c-qcam module to add a parport=xxx
 option as in the bw-qcam module so you can specify the parallel port:

        insmod -v c-qcam parport=0

 And bypass the detection code, see ../../drivers/char/c-qcam.c and
 look for the 'qc_detect' code and call.

   Note that there is work in progress to change the video4linux API,
 this work is documented at the video4linux2 site listed below.


 9.0 --- A sample program using v4lgrabber,

 v4lgrab is a simple image grabber that will copy a frame from the
 first video device, /dev/video0 to standard output in portable pixmap
 format (.ppm)  To produce .jpg output, you can use it like this:
 'v4lgrab | convert - c-qcam.jpg'


 10.0 --- Other Information

 Use the ../../Maintainers file, particularly the  VIDEO FOR LINUX and PARALLEL
 PORT SUPPORT sections

 The video4linux page:
   http://linuxtv.org

 The V4L2 API spec:
   http://v4l2spec.bytesex.org/

 Some web pages about the quickcams:
    http://www.pingouin-land.com/howto/QuickCam-HOWTO.html

    http://www.crynwr.com/qcpc/            QuickCam Third-Party Drivers
    http://www.crynwr.com/qcpc/re.html     Some Reverse Engineering
    http://www.wirelesscouch.net/software/gqcam/   v4l client
    http://phobos.illtel.denver.co.us/pub/qcread/ doesn't use v4l
    ftp://ftp.cs.unm.edu/pub/chris/quickcam/   Has lots of drivers
    http://www.cs.duke.edu/~reynolds/quickcam/ Has lots of information
	c-qcam - Connectix Color QuickCam video4linux kernel driver

	Copyright (C) 1999 Dave Forrest <drf5n@virginia.edu>
	released under GNU GPL.

	1999-12-08 Dave Forrest, written with kernel version 2.2.12 in mind


	Table of Contents

	1.0 Introduction
	2.0 Compilation, Installation, and Configuration
	3.0 Troubleshooting
	4.0 Future Work / current work arounds
	9.0 Sample Program, v4lgrab
	10.0 Other Information


	1.0 Introduction

	The file ../../drivers/media/video/c-qcam.c is a device driver for
	the Logitech (nee Connectix) parallel port interface color CCD camera.
	This is a fairly inexpensive device for capturing images. Logitech
	does not currently provide information for developers, but many people
	have engineered several solutions for non-Microsoft use of the Color
	Quickcam.

	1.1 Motivation

	I spent a number of hours trying to get my camera to work, and I
	hope this document saves you some time. My camera will not work with
	the 2.2.13 kernel as distributed, but with a few patches to the
	module, I was able to grab some frames. See 4.0, Future Work.



	2.0 Compilation, Installation, and Configuration

	The c-qcam depends on parallel port support, video4linux, and the
	Color Quickcam. It is also nice to have the parallel port readback
	support enabled. I enabled these as modules during the kernel
	configuration. The appropriate flags are:

	CONFIG_PRINTER M for lp.o, parport.o parport_pc.o modules
	CONFIG_PNP_PARPORT M for autoprobe.o IEEE1284 readback module
	CONFIG_PRINTER_READBACK M for parport_probe.o IEEE1284 readback module
	CONFIG_VIDEO_DEV M for videodev.o video4linux module
	CONFIG_VIDEO_CQCAM M for c-qcam.o Color Quickcam module

	With these flags, the kernel should compile and install the modules.
	To record and monitor the compilation, I use:

	(make zlilo ; \
	make modules; \
	make modules_install ;
	depmod -a ) &>log &
	less log # then a capital 'F' to watch the progress

	But that is my personal preference.

	2.2 Configuration

	The configuration requires module configuration and device
	configuration. I like kmod or kerneld process with the
	/etc/modprobe.conf file so the modules can automatically load/unload as
	they are used. The video devices could already exist, be generated
	using MAKEDEV, or need to be created. The following sections detail
	these procedures.


	2.1 Module Configuration

	Using modules requires a bit of work to install and pass the
	parameters. Understand that entries in /etc/modprobe.conf of:

	alias parport_lowlevel parport_pc
	options parport_pc io=0x378 irq=none
	alias char-major-81 videodev
	alias char-major-81-0 c-qcam

	will cause the kmod/modprobe to do certain things. If you are
	using kmod, then a request for a 'char-major-81-0' will cause
	the 'c-qcam' module to load. If you have other video sources with
	modules, you might want to assign the different minor numbers to
	different modules.

	2.2 Device Configuration

	At this point, we need to ensure that the device files exist.
	Video4linux used the /dev/video* files, and we want to attach the
	Quickcam to one of these.

	ls -lad /dev/video* # should produce a list of the video devices

	If the video devices do not exist, you can create them with:

	su
	cd /dev
	for ii in 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 ; do
	mknod video$ii c 81 $ii # char-major-81-[0-16]
	chown root.root video$ii # owned by root
	chmod 600 video$ii # read/writable by root only
	done

	Lots of people connect video0 to video and bttv, but you might want
	your c-qcam to mean something more:

	ln -s video0 c-qcam # make /dev/c-qcam a working file
	ln -s c-qcam video # make /dev/c-qcam your default video source

	But these are conveniences. The important part is to make the proper
	special character files with the right major and minor numbers. All
	of the special device files are listed in ../devices.txt. If you
	would like the c-qcam readable by non-root users, you will need to
	change the permissions.

	3.0 Troubleshooting

	If the sample program below, v4lgrab, gives you output then
	everything is working.

	v4lgrab \| wc # should give you a count of characters

	Otherwise, you have some problem.

	The c-qcam is IEEE1284 compatible, so if you are using the proc file
	system (CONFIG_PROC_FS), the parallel printer support
	(CONFIG_PRINTER), the IEEE 1284 system,(CONFIG_PRINTER_READBACK), you
	should be able to read some identification from your quickcam with

	modprobe -v parport
	modprobe -v parport_probe
	cat /proc/parport/PORTNUMBER/autoprobe
	Returns:
	CLASS:MEDIA;
	MODEL:Color QuickCam 2.0;
	MANUFACTURER:Connectix;

	A good response to this indicates that your color quickcam is alive
	and well. A common problem is that the current driver does not
	reliably detect a c-qcam, even though one is attached. In this case,

	modprobe -v c-qcam
	or
	insmod -v c-qcam

	Returns a message saying "Device or resource busy" Development is
	currently underway, but a workaround is to patch the module to skip
	the detection code and attach to a defined port. Check the
	video4linux mailing list and archive for more current information.

	3.1 Checklist:

	Can you get an image?
	v4lgrab >qcam.ppm ; wc qcam.ppm ; xv qcam.ppm

	Is a working c-qcam connected to the port?
	grep ^ /proc/parport/?/autoprobe

	Do the /dev/video* files exist?
	ls -lad /dev/video

	Is the c-qcam module loaded?
	modprobe -v c-qcam ; lsmod

	Does the camera work with alternate programs? cqcam, etc?




	4.0 Future Work / current workarounds

	It is hoped that this section will soon become obsolete, but if it
	isn't, you might try patching the c-qcam module to add a parport=xxx
	option as in the bw-qcam module so you can specify the parallel port:

	insmod -v c-qcam parport=0

	And bypass the detection code, see ../../drivers/char/c-qcam.c and
	look for the 'qc_detect' code and call.

	Note that there is work in progress to change the video4linux API,
	this work is documented at the video4linux2 site listed below.


	9.0 --- A sample program using v4lgrabber,

	v4lgrab is a simple image grabber that will copy a frame from the
	first video device, /dev/video0 to standard output in portable pixmap
	format (.ppm) To produce .jpg output, you can use it like this:
	'v4lgrab \| convert - c-qcam.jpg'


	10.0 --- Other Information

	Use the ../../Maintainers file, particularly the VIDEO FOR LINUX and PARALLEL
	PORT SUPPORT sections

	The video4linux page:
	http://linuxtv.org

	The V4L2 API spec:
	http://v4l2spec.bytesex.org/

	Some web pages about the quickcams:
	http://www.pingouin-land.com/howto/QuickCam-HOWTO.html

	http://www.crynwr.com/qcpc/ QuickCam Third-Party Drivers
	http://www.crynwr.com/qcpc/re.html Some Reverse Engineering
	http://www.wirelesscouch.net/software/gqcam/ v4l client
	http://phobos.illtel.denver.co.us/pub/qcread/ doesn't use v4l
	ftp://ftp.cs.unm.edu/pub/chris/quickcam/ Has lots of drivers
	http://www.cs.duke.edu/~reynolds/quickcam/ Has lots of information