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413 lines
13 KiB
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413 lines
13 KiB
Plaintext
c-qcam - Connectix Color QuickCam video4linux kernel driver
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Copyright (C) 1999 Dave Forrest <drf5n@virginia.edu>
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released under GNU GPL.
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1999-12-08 Dave Forrest, written with kernel version 2.2.12 in mind
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Table of Contents
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1.0 Introduction
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2.0 Compilation, Installation, and Configuration
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3.0 Troubleshooting
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4.0 Future Work / current work arounds
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9.0 Sample Program, v4lgrab
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10.0 Other Information
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1.0 Introduction
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The file ../drivers/char/c-qcam.c is a device driver for the
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Logitech (nee Connectix) parallel port interface color CCD camera.
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This is a fairly inexpensive device for capturing images. Logitech
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does not currently provide information for developers, but many people
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have engineered several solutions for non-Microsoft use of the Color
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Quickcam.
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1.1 Motivation
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I spent a number of hours trying to get my camera to work, and I
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hope this document saves you some time. My camera will not work with
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the 2.2.13 kernel as distributed, but with a few patches to the
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module, I was able to grab some frames. See 4.0, Future Work.
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2.0 Compilation, Installation, and Configuration
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The c-qcam depends on parallel port support, video4linux, and the
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Color Quickcam. It is also nice to have the parallel port readback
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support enabled. I enabled these as modules during the kernel
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configuration. The appropriate flags are:
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CONFIG_PRINTER M for lp.o, parport.o parport_pc.o modules
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CONFIG_PNP_PARPORT M for autoprobe.o IEEE1284 readback module
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CONFIG_PRINTER_READBACK M for parport_probe.o IEEE1284 readback module
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CONFIG_VIDEO_DEV M for videodev.o video4linux module
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CONFIG_VIDEO_CQCAM M for c-qcam.o Color Quickcam module
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With these flags, the kernel should compile and install the modules.
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To record and monitor the compilation, I use:
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(make zlilo ; \
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make modules; \
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make modules_install ;
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depmod -a ) &>log &
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less log # then a capital 'F' to watch the progress
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But that is my personal preference.
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2.2 Configuration
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The configuration requires module configuration and device
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configuration. I like kmod or kerneld process with the
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/etc/modprobe.conf file so the modules can automatically load/unload as
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they are used. The video devices could already exist, be generated
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using MAKEDEV, or need to be created. The following sections detail
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these procedures.
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2.1 Module Configuration
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Using modules requires a bit of work to install and pass the
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parameters. Understand that entries in /etc/modprobe.conf of:
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alias parport_lowlevel parport_pc
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options parport_pc io=0x378 irq=none
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alias char-major-81 videodev
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alias char-major-81-0 c-qcam
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will cause the kmod/modprobe to do certain things. If you are
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using kmod, then a request for a 'char-major-81-0' will cause
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the 'c-qcam' module to load. If you have other video sources with
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modules, you might want to assign the different minor numbers to
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different modules.
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2.2 Device Configuration
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At this point, we need to ensure that the device files exist.
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Video4linux used the /dev/video* files, and we want to attach the
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Quickcam to one of these.
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ls -lad /dev/video* # should produce a list of the video devices
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If the video devices do not exist, you can create them with:
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su
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cd /dev
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for ii in 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 ; do
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mknod video$ii c 81 $ii # char-major-81-[0-16]
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chown root.root video$ii # owned by root
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chmod 600 video$ii # read/writable by root only
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done
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Lots of people connect video0 to video and bttv, but you might want
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your c-qcam to mean something more:
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ln -s video0 c-qcam # make /dev/c-qcam a working file
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ln -s c-qcam video # make /dev/c-qcam your default video source
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But these are conveniences. The important part is to make the proper
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special character files with the right major and minor numbers. All
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of the special device files are listed in ../devices.txt. If you
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would like the c-qcam readable by non-root users, you will need to
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change the permissions.
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3.0 Troubleshooting
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If the sample program below, v4lgrab, gives you output then
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everything is working.
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v4lgrab | wc # should give you a count of characters
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Otherwise, you have some problem.
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The c-qcam is IEEE1284 compatible, so if you are using the proc file
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system (CONFIG_PROC_FS), the parallel printer support
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(CONFIG_PRINTER), the IEEE 1284 system,(CONFIG_PRINTER_READBACK), you
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should be able to read some identification from your quickcam with
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modprobe -v parport
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modprobe -v parport_probe
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cat /proc/parport/PORTNUMBER/autoprobe
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Returns:
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CLASS:MEDIA;
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MODEL:Color QuickCam 2.0;
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MANUFACTURER:Connectix;
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A good response to this indicates that your color quickcam is alive
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and well. A common problem is that the current driver does not
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reliably detect a c-qcam, even though one is attached. In this case,
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modprobe -v c-qcam
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or
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insmod -v c-qcam
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Returns a message saying "Device or resource busy" Development is
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currently underway, but a workaround is to patch the module to skip
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the detection code and attach to a defined port. Check the
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video4linux mailing list and archive for more current information.
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3.1 Checklist:
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Can you get an image?
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v4lgrab >qcam.ppm ; wc qcam.ppm ; xv qcam.ppm
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Is a working c-qcam connected to the port?
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grep ^ /proc/parport/?/autoprobe
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Do the /dev/video* files exist?
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ls -lad /dev/video
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Is the c-qcam module loaded?
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modprobe -v c-qcam ; lsmod
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Does the camera work with alternate programs? cqcam, etc?
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4.0 Future Work / current workarounds
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It is hoped that this section will soon become obsolete, but if it
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isn't, you might try patching the c-qcam module to add a parport=xxx
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option as in the bw-qcam module so you can specify the parallel port:
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insmod -v c-qcam parport=0
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And bypass the detection code, see ../../drivers/char/c-qcam.c and
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look for the 'qc_detect' code and call.
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Note that there is work in progress to change the video4linux API,
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this work is documented at the video4linux2 site listed below.
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9.0 --- A sample program using v4lgrabber,
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This program is a simple image grabber that will copy a frame from the
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first video device, /dev/video0 to standard output in portable pixmap
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format (.ppm) Using this like: 'v4lgrab | convert - c-qcam.jpg'
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produced this picture of me at
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http://mug.sys.virginia.edu/~drf5n/extras/c-qcam.jpg
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-------------------- 8< ---------------- 8< -----------------------------
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/* Simple Video4Linux image grabber. */
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/*
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* Video4Linux Driver Test/Example Framegrabbing Program
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*
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* Compile with:
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* gcc -s -Wall -Wstrict-prototypes v4lgrab.c -o v4lgrab
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* Use as:
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* v4lgrab >image.ppm
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*
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* Copyright (C) 1998-05-03, Phil Blundell <philb@gnu.org>
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* Copied from http://www.tazenda.demon.co.uk/phil/vgrabber.c
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* with minor modifications (Dave Forrest, drf5n@virginia.edu).
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*
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*/
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <sys/ioctl.h>
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#include <stdlib.h>
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#include <linux/types.h>
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#include <linux/videodev.h>
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#define FILE "/dev/video0"
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/* Stole this from tvset.c */
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#define READ_VIDEO_PIXEL(buf, format, depth, r, g, b) \
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{ \
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switch (format) \
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{ \
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case VIDEO_PALETTE_GREY: \
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switch (depth) \
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{ \
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case 4: \
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case 6: \
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case 8: \
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(r) = (g) = (b) = (*buf++ << 8);\
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break; \
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\
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case 16: \
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(r) = (g) = (b) = \
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*((unsigned short *) buf); \
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buf += 2; \
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break; \
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} \
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break; \
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\
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\
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case VIDEO_PALETTE_RGB565: \
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{ \
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unsigned short tmp = *(unsigned short *)buf; \
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(r) = tmp&0xF800; \
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(g) = (tmp<<5)&0xFC00; \
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(b) = (tmp<<11)&0xF800; \
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buf += 2; \
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} \
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break; \
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\
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case VIDEO_PALETTE_RGB555: \
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(r) = (buf[0]&0xF8)<<8; \
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(g) = ((buf[0] << 5 | buf[1] >> 3)&0xF8)<<8; \
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(b) = ((buf[1] << 2 ) & 0xF8)<<8; \
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buf += 2; \
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break; \
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\
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case VIDEO_PALETTE_RGB24: \
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(r) = buf[0] << 8; (g) = buf[1] << 8; \
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(b) = buf[2] << 8; \
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buf += 3; \
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break; \
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\
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default: \
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fprintf(stderr, \
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"Format %d not yet supported\n", \
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format); \
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} \
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}
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int get_brightness_adj(unsigned char *image, long size, int *brightness) {
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long i, tot = 0;
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for (i=0;i<size*3;i++)
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tot += image[i];
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*brightness = (128 - tot/(size*3))/3;
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return !((tot/(size*3)) >= 126 && (tot/(size*3)) <= 130);
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}
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int main(int argc, char ** argv)
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{
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int fd = open(FILE, O_RDONLY), f;
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struct video_capability cap;
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struct video_window win;
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struct video_picture vpic;
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unsigned char *buffer, *src;
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int bpp = 24, r, g, b;
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unsigned int i, src_depth;
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if (fd < 0) {
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perror(FILE);
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exit(1);
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}
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if (ioctl(fd, VIDIOCGCAP, &cap) < 0) {
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perror("VIDIOGCAP");
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fprintf(stderr, "(" FILE " not a video4linux device?)\n");
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close(fd);
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exit(1);
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}
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if (ioctl(fd, VIDIOCGWIN, &win) < 0) {
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perror("VIDIOCGWIN");
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close(fd);
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exit(1);
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}
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if (ioctl(fd, VIDIOCGPICT, &vpic) < 0) {
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perror("VIDIOCGPICT");
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close(fd);
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exit(1);
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}
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if (cap.type & VID_TYPE_MONOCHROME) {
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vpic.depth=8;
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vpic.palette=VIDEO_PALETTE_GREY; /* 8bit grey */
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if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
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vpic.depth=6;
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if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
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vpic.depth=4;
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if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
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fprintf(stderr, "Unable to find a supported capture format.\n");
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close(fd);
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exit(1);
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}
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}
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}
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} else {
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vpic.depth=24;
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vpic.palette=VIDEO_PALETTE_RGB24;
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if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
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vpic.palette=VIDEO_PALETTE_RGB565;
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vpic.depth=16;
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if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
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vpic.palette=VIDEO_PALETTE_RGB555;
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vpic.depth=15;
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if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
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fprintf(stderr, "Unable to find a supported capture format.\n");
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return -1;
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}
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}
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}
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}
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buffer = malloc(win.width * win.height * bpp);
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if (!buffer) {
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fprintf(stderr, "Out of memory.\n");
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exit(1);
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}
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do {
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int newbright;
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read(fd, buffer, win.width * win.height * bpp);
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f = get_brightness_adj(buffer, win.width * win.height, &newbright);
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if (f) {
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vpic.brightness += (newbright << 8);
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if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
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perror("VIDIOSPICT");
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break;
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}
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}
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} while (f);
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fprintf(stdout, "P6\n%d %d 255\n", win.width, win.height);
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src = buffer;
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for (i = 0; i < win.width * win.height; i++) {
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READ_VIDEO_PIXEL(src, vpic.palette, src_depth, r, g, b);
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fputc(r>>8, stdout);
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fputc(g>>8, stdout);
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fputc(b>>8, stdout);
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}
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close(fd);
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return 0;
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}
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-------------------- 8< ---------------- 8< -----------------------------
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10.0 --- Other Information
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Use the ../../Maintainers file, particularly the VIDEO FOR LINUX and PARALLEL
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PORT SUPPORT sections
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The video4linux page:
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http://roadrunner.swansea.linux.org.uk/v4l.shtml
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The video4linux2 page:
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http://millennium.diads.com/bdirks/v4l2.htm
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Some web pages about the quickcams:
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http://www.dkfz-heidelberg.de/Macromol/wedemann/mini-HOWTO-cqcam.html
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http://www.crynwr.com/qcpc/ QuickCam Third-Party Drivers
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http://www.crynwr.com/qcpc/re.html Some Reverse Engineering
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http://cse.unl.edu/~cluening/gqcam/ v4l client
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http://phobos.illtel.denver.co.us/pub/qcread/ doesn't use v4l
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ftp://ftp.cs.unm.edu/pub/chris/quickcam/ Has lots of drivers
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http://www.cs.duke.edu/~reynolds/quickcam/ Has lots of information
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