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NAME

       vgrabbj - grab images from a v4l-compatible webcam

SYNOPSIS

       vgrabbj [options]

DESCRIPTION

       This manual page documents briefly the vgrabbj command.

       vgrabbj  is a program that will grab images from any v4l-capable device
       which supports one of the  rgb24,  rgb32,  yuv420,  yuv420p,  yuyv,  or
       yuv422 palettes and saves the image as a .jpg, .png, or .pnm file.

       Optional,  it  can timestamp the resulting image, and/or upload it to a
       ftp-server. Additionally, a daemon-mode is available to  do  the  above
       regularly.

       On  startup,  the  default configuration file /etc/vgrabbj.conf is read
       and evaluated.  If  a  configuration  file  is  specified  via  the  -c
       parameter  (see  below), that file is read and parsed. Values which are
       present in the default config file keep  their  values.   Finally,  the
       commandline is evaluated. If an option is presented more than once, the
       last in the commandline is taken.  If no options given,  vgrabbj  tries
       to  open the default v4l-device /dev/video, grab an image and return it
       on /dev/stdout.  So be aware.

OPTIONS

       All options are either numeric values, strings, or booleans. If it is a
       boolean  switch  (e.g.  no  value/string  shown  after  the switch), it
       plainly  switches  the  current  setting  of  that  particular  option.
       Remember,  vgrabbj.conf  is  read first, so any option set to on or off
       there will be toggled by the commandline switch.

       -h     Show summary of  options  and  version  number.   -c  <filename>
              Specifies filename as alternative configuration file.

       -l <seconds>
              Daemonize & loop with seconds intervals (min. 1).

       -L <microseconds>
              Daemonize  &  loop  microseconds  intervals (min. 1). Same as -l
              except you can control it more precisely.

       -a     Enable vgrabbj's brightness adjustment (default:  disabled).  To
              use vgrabbj's brightness adjustment, RGB24 support of the device
              is necessary. You may have to provide it to your device via  the
              -F  parameter  (see  below).   If  your  device does not support
              RGB24, this setting is silently ignored.

       -q <quality>
              Sets the quality of a jpeg output to  quality  (1-100,  default:
              75).

       -i <imagesize>
              Sets the imagesize of input device, where imagesize is one of:

               sqcif= 128x96,     qsif = 160x120,
               qcif = 176x144,    sif  = 320x240,
               cif  = 352x288,    vga  = 640x480,
               svga = 800x600,    xga  = 1024x768,
               sxga = 1280x1024,  uxga = 1600x1200,

              (default: cif)

       -w <width>
              Sets  the width of the image to width. Needs -H.  The v4l-device
              has to support the image width you set with this option.

       -H <height>
              Sets the height of the image to  height.  Needs  -w.   The  v4l-
              device has to support the image height you set with this option.

       -o <format>
              Sets the output to format (either jpeg, png,  or  pnm,  default:
              jpeg)

       -f <filename>
              Output is written to filename (default: /dev/stdout)

       -A <path+filename>
              Additional  to  the  output of -f another file is written to the
              named  path+filename,  whereas  the  whole  may   be   formatted
              according  to  strftime(2).  This  enables  the  creation  of an
              archive of images. Currently, the output is  only  supported  on
              the same filesystem as the original output.

       -E <value>
              Defines  how  many  images  shall  be  read until a copy for the
              archive is made. E.g. 1 means each image taken is  also  put  in
              the archive.  5 would mean every fifth image taken is put in the
              archive.

       -M <value>
              Sets the maximum number of images kept in the  archive.  If  you
              defined  5  seconds  for  daemon  mode, archive every image, you
              collect 720 images per hour. If you set this switch to  720  you
              would keep an hour of images in the archive.

       -d <device>
              Sets the input device to device (default: /dev/video)

       -s <device>
              This  flag  causes  vgrabbj  to  print  the  v4l capabilities of
              <device> and exit.

       -C     Causes vgrabbj to open the  device  only  while  image  data  is
              grabbed.   This  is  helpful  if  you  need access to the device
              besides  vgrabbj.  It's  use  is  discouraged  due  to  possible
              problems with memory fragmentation.  Default is to keep the v4l-
              device open while vgrabbj is running.

       -g     Disables setting  of  the  image  size  (see  -i,  -H,  and  -w.
              Necessary for certain v4l-devices which do not support to be set
              to a particular image size  (e.g.  IBM-usb-cam,  QuickCam).  For
              these  devices you have to specify the size at module load time.

       -S     Switches colormap from BGR to RGB (or vice versa).  Use  if  you
              have odd colors.

       -R     Swaps left and right of the image like a mirror.

       -U     Swaps  top  and  bottom  of  the  image  like a mirror (e.g. for
              upside-down montage of the cam).

       -G     Turns  off  use  of  mmap'ed  memory.  see  vgrabbj.conf(5)  for
              details.

       -D <value>
              Sets the loglevel of vgrabbj. Valid for value are 0, 2, 3, 4, 6,
              7 (default: 4). 0 means no messages at all, 7  is  debug.  Don't
              use  7  if  you are running vgrabbj in daemon mode, it'll surely
              fill your syslog. Be aware, that loglevel 7 will also write your
              ftp-password (if defined in vgrabbj.conf(5)) in the logfile!

       -n     Disable  the  use of the temporary outputfile and write directly
              to the output-file specified with -f. Output to  /dev/stdout  is
              always written directly without the use of a temporary file.  If
              a filename different from /dev/stdout  was  given  with  the  -f
              parameter,  vgrabbj  defaults  to  use  a  temporary file called
              filename.tmp to write the image. This file is  then  renamed  to
              filename  to  shorten  the  time period corrupt data may be read
              from filename.

       -F <palette>
              Force the usage of the specified  palette.  If  palette  is  not
              supported  by  either  vgrabbj  or the v4l-device, fallback to a
              palette supported by both is provided. If no common  denominator
              is  available,  vgrabbj  exits.  See  DESCRIPTION for details on
              palettes supported by vgrabbj. Possible values  are  (copy  from
              videodev.h):

               1  VIDEO_PALETTE_GREY      Linear greyscale
               2  VIDEO_PALETTE_HI240     High 240 cube (BT848)
               3  VIDEO_PALETTE_RGB565    565 16 bit RGB
               4  VIDEO_PALETTE_RGB24     24bit RGB
               5  VIDEO_PALETTE_RGB32     32bit RGB
               6  VIDEO_PALETTE_RGB555    555 15bit RGB
               7  VIDEO_PALETTE_YUV422    YUV422 capture
               8  VIDEO_PALETTE_YUYV
               9  VIDEO_PALETTE_UYVY
               10 VIDEO_PALETTE_YUV420
               10 VIDEO_PALETTE_YUV411    YUV411 capture
               11 VIDEO_PALETTE_RAW       RAW capture (BT848)
               12 VIDEO_PALETTE_YUV422P   YUV 4:2:2 Planar
               13 VIDEO_PALETTE_YUV411P   YUV 4:1:1 Planar
               14 VIDEO_PALETTE_YUV420P   YUV 4:2:0 Planar
               15 VIDEO_PALETTE_YUV410P   YUV 4:1:0 Planar
               16 VIDEO_PALETTE_PLANAR
               17 VIDEO_PALETTE_COMPONENT

              (no default, depends on v4l-device)

       -z <value>
              value  images  are  grabbed  and immediately discarded. Only the
              last image is written to the output. This might  be  helpful  if
              your  v4l-device needs to take a couple of images to auto-adjust
              to the current light.

       -X     Does not fork daemon process and keeps vgrabbj in daemon mode in
              foreground,  attached  to  the  terminal.  Useful  for debugging
              purpose. Not available in config file.

HARDWARE CONTROL OPTIONS

       With the following options you can control  the  hardware  settings  of
       your  cam - if it is supported by your cam. Be aware that these options
       might break your hardware, as there is no  check  on  what  values  are
       available, allowed, and supported by your hardware.

       -W <value>
              Whiteness definition.

       -r <value>
              Color definition.

       -x <value>
              Contrast definition.

       -b <value>
              Brightness definition.

       -u <value>
              Hue definition.

TIMESTAMP OPTIONS

       The  following  options are available only if vgrabbj was compiled with
       the freetype library available. If you set any one of these options  on
       the  commandline  timestamp will be enabled with default values for all
       other options.

       -e     Switches timestamp to be used or not. Default is off, but may be
              overriden  by  config-file, so just try to enable this switch if
              there is no timestamp in the resulting image.

       -t <filename>
              The  TrueType  font  to  be  used  for  the  timestamp  (default
              /usr/X11R6/lib/X11/fonts/TrueType/Arialn.ttf)

       -T <size>
              Set the fontsize to size for timestamp (3-100, default: 12).

       -p "<format-str>"
              Defines  the  timestamp.  format-str  can  be  plain text or any
              strftime format and has to be enclosed with '""' (default:  "%a,
              %e.  %B %Y - %T" - see strftime(3) for details)

       -P <value>
              Alignment of the timestamp in the image. Possible value:

              0 = upper left,    1 = upper right,
              2 = lower left,    3 = lower right,
              4 = upper center,  5 = lower center

              (default: 1).

       -m <value>
              Defines  the  blend  between  font  background and image (1-100,
              default: 60).

       -B <value>
              value pixels will be used as border around the timestamp  string
              (1-255, default: 2).

FTP OPTIONS

       There are no options for ftp-upload on the command line. This is due to
       the need to provide a password which would be  visible  via  the  ps(1)
       command.  See  vgrabbj.conf for details on how to set-up the ftp-upload
       option.  Additionally, vgrabbj has to be compiled with libftp  support.

BUGS

       %F  in  the  archive  time-string  (year  with  century)  causes memory
       corruption at a pentium-machine running  vgrabbj  (not  validated).  No
       further bugs are known at this time.

SEE ALSO

       vgrabbj.conf(4), strftime(3), ps(1)

AUTHOR

       This   manual   page   was   originally   written  by  Michael  Janssen
       <janssen@cns.uni.edu>, for the Debian GNU/Linux system and enhanced  by
       Jens Gecius <devel@gecius.de>.

                              February  24, 2002