GNU.WIKI: The GNU/Linux Knowledge Base

  [HOME] [PHP Manual] [HowTo] [ABS] [MAN1] [MAN2] [MAN3] [MAN4] [MAN5] [MAN6] [MAN7] [MAN8] [MAN9]

  [0-9] [Aa] [Bb] [Cc] [Dd] [Ee] [Ff] [Gg] [Hh] [Ii] [Jj] [Kk] [Ll] [Mm] [Nn] [Oo] [Pp] [Qq] [Rr] [Ss] [Tt] [Uu] [Vv] [Ww] [Xx] [Yy] [Zz]


       vgrabbj - grab images from a v4l-compatible webcam


       vgrabbj [options]


       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, uyvy, 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

       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/video0, grab an image and return it
       on /dev/stdout.  So be aware.


       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:

       -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:

       -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

       -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/video0)

       -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

       -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.

       -Z 'commands'
              Ask  vgrabbj  to launch an external program. May be used to pass
              the picture through ImageMagick or  others  filters.  The  first
              '%s'  instance  in  the  command  line  will  be  replaced  with
              filename. If UseTmpOut is On, 'commands' will be run before  the
              file is renamed.

       -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

               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

              (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.


       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.


       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
              overridden 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

       -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).


       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.


       %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.


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


       This   manual   page   was   originally   written  by  Michael  Janssen
       <>, for the Debian GNU/Linux system and enhanced  by
       Jens Gecius <>.

                              February  24, 2002                    VGRABBJ(1)

  All copyrights belong to their respective owners. Other content (c) 2014-2018, GNU.WIKI. Please report site errors to
Page load time: 0.085 seconds. Last modified: November 04 2018 12:49:43.