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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/video4linux/CQcam.txt
downloadlinux-stericsson-2.6.12-rc2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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+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/char/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,
+
+This program 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) Using this like: 'v4lgrab | convert - c-qcam.jpg'
+produced this picture of me at
+ http://mug.sys.virginia.edu/~drf5n/extras/c-qcam.jpg
+
+-------------------- 8< ---------------- 8< -----------------------------
+
+/* Simple Video4Linux image grabber. */
+/*
+ * Video4Linux Driver Test/Example Framegrabbing Program
+ *
+ * Compile with:
+ * gcc -s -Wall -Wstrict-prototypes v4lgrab.c -o v4lgrab
+ * Use as:
+ * v4lgrab >image.ppm
+ *
+ * Copyright (C) 1998-05-03, Phil Blundell <philb@gnu.org>
+ * Copied from http://www.tazenda.demon.co.uk/phil/vgrabber.c
+ * with minor modifications (Dave Forrest, drf5n@virginia.edu).
+ *
+ */
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <stdlib.h>
+
+#include <linux/types.h>
+#include <linux/videodev.h>
+
+#define FILE "/dev/video0"
+
+/* Stole this from tvset.c */
+
+#define READ_VIDEO_PIXEL(buf, format, depth, r, g, b) \
+{ \
+ switch (format) \
+ { \
+ case VIDEO_PALETTE_GREY: \
+ switch (depth) \
+ { \
+ case 4: \
+ case 6: \
+ case 8: \
+ (r) = (g) = (b) = (*buf++ << 8);\
+ break; \
+ \
+ case 16: \
+ (r) = (g) = (b) = \
+ *((unsigned short *) buf); \
+ buf += 2; \
+ break; \
+ } \
+ break; \
+ \
+ \
+ case VIDEO_PALETTE_RGB565: \
+ { \
+ unsigned short tmp = *(unsigned short *)buf; \
+ (r) = tmp&0xF800; \
+ (g) = (tmp<<5)&0xFC00; \
+ (b) = (tmp<<11)&0xF800; \
+ buf += 2; \
+ } \
+ break; \
+ \
+ case VIDEO_PALETTE_RGB555: \
+ (r) = (buf[0]&0xF8)<<8; \
+ (g) = ((buf[0] << 5 | buf[1] >> 3)&0xF8)<<8; \
+ (b) = ((buf[1] << 2 ) & 0xF8)<<8; \
+ buf += 2; \
+ break; \
+ \
+ case VIDEO_PALETTE_RGB24: \
+ (r) = buf[0] << 8; (g) = buf[1] << 8; \
+ (b) = buf[2] << 8; \
+ buf += 3; \
+ break; \
+ \
+ default: \
+ fprintf(stderr, \
+ "Format %d not yet supported\n", \
+ format); \
+ } \
+}
+
+int get_brightness_adj(unsigned char *image, long size, int *brightness) {
+ long i, tot = 0;
+ for (i=0;i<size*3;i++)
+ tot += image[i];
+ *brightness = (128 - tot/(size*3))/3;
+ return !((tot/(size*3)) >= 126 && (tot/(size*3)) <= 130);
+}
+
+int main(int argc, char ** argv)
+{
+ int fd = open(FILE, O_RDONLY), f;
+ struct video_capability cap;
+ struct video_window win;
+ struct video_picture vpic;
+
+ unsigned char *buffer, *src;
+ int bpp = 24, r, g, b;
+ unsigned int i, src_depth;
+
+ if (fd < 0) {
+ perror(FILE);
+ exit(1);
+ }
+
+ if (ioctl(fd, VIDIOCGCAP, &cap) < 0) {
+ perror("VIDIOGCAP");
+ fprintf(stderr, "(" FILE " not a video4linux device?)\n");
+ close(fd);
+ exit(1);
+ }
+
+ if (ioctl(fd, VIDIOCGWIN, &win) < 0) {
+ perror("VIDIOCGWIN");
+ close(fd);
+ exit(1);
+ }
+
+ if (ioctl(fd, VIDIOCGPICT, &vpic) < 0) {
+ perror("VIDIOCGPICT");
+ close(fd);
+ exit(1);
+ }
+
+ if (cap.type & VID_TYPE_MONOCHROME) {
+ vpic.depth=8;
+ vpic.palette=VIDEO_PALETTE_GREY; /* 8bit grey */
+ if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
+ vpic.depth=6;
+ if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
+ vpic.depth=4;
+ if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
+ fprintf(stderr, "Unable to find a supported capture format.\n");
+ close(fd);
+ exit(1);
+ }
+ }
+ }
+ } else {
+ vpic.depth=24;
+ vpic.palette=VIDEO_PALETTE_RGB24;
+
+ if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
+ vpic.palette=VIDEO_PALETTE_RGB565;
+ vpic.depth=16;
+
+ if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
+ vpic.palette=VIDEO_PALETTE_RGB555;
+ vpic.depth=15;
+
+ if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
+ fprintf(stderr, "Unable to find a supported capture format.\n");
+ return -1;
+ }
+ }
+ }
+ }
+
+ buffer = malloc(win.width * win.height * bpp);
+ if (!buffer) {
+ fprintf(stderr, "Out of memory.\n");
+ exit(1);
+ }
+
+ do {
+ int newbright;
+ read(fd, buffer, win.width * win.height * bpp);
+ f = get_brightness_adj(buffer, win.width * win.height, &newbright);
+ if (f) {
+ vpic.brightness += (newbright << 8);
+ if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
+ perror("VIDIOSPICT");
+ break;
+ }
+ }
+ } while (f);
+
+ fprintf(stdout, "P6\n%d %d 255\n", win.width, win.height);
+
+ src = buffer;
+
+ for (i = 0; i < win.width * win.height; i++) {
+ READ_VIDEO_PIXEL(src, vpic.palette, src_depth, r, g, b);
+ fputc(r>>8, stdout);
+ fputc(g>>8, stdout);
+ fputc(b>>8, stdout);
+ }
+
+ close(fd);
+ return 0;
+}
+-------------------- 8< ---------------- 8< -----------------------------
+
+
+10.0 --- Other Information
+
+Use the ../../Maintainers file, particularly the VIDEO FOR LINUX and PARALLEL
+PORT SUPPORT sections
+
+The video4linux page:
+ http://roadrunner.swansea.linux.org.uk/v4l.shtml
+
+The video4linux2 page:
+ http://millennium.diads.com/bdirks/v4l2.htm
+
+Some web pages about the quickcams:
+ http://www.dkfz-heidelberg.de/Macromol/wedemann/mini-HOWTO-cqcam.html
+
+ http://www.crynwr.com/qcpc/ QuickCam Third-Party Drivers
+ http://www.crynwr.com/qcpc/re.html Some Reverse Engineering
+ http://cse.unl.edu/~cluening/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
+
+