NAME

       webcam - capture images and upload them to a webserver using ftp

SYNOPSIS

       webcam [ config file ]

DESCRIPTION

       webcam captures images from a video4linux device like bttv, annotates them and and uploads
       them to a webserver using ftp in a endless loop.

CONFIGURATION

       At startup webcam reads the configuration from the given config  file  or  ~/.webcamrc  if
       none is specified in the command line.

       The  config  file  has  at  least  two  sections.   The  "grab"  section holds the capture
       parameters.  Any other section describes  where  the  image  should  be  uploaded.   Older
       versions used "ftp" as name for that section.  Recently the webcam utility got support for
       multiple connections, thus any section name is accepted and you can have more than one ftp
       section  (you  have  to  use  another  name for each section througth, name them by upload
       servers for example).

       Here is an sample config file (the given values are the defaults):

       [grab]
       device = /dev/video0
       driver = libv4l
       text = "webcam %Y-%m-%d %H:%M:%S"
       infofile = filename
       fg_red = 255
       fg_green = 255
       fg_blue = 255
       width = 320
       height = 240
       delay = 3
       wait = 0
       input = composite1
       norm = pal
       rotate = 0
       top = 0
       left = 0
       bottom = -1
       right = -1
       quality = 75
       trigger = 0
       once = 0

       [ftp]
       host = www
       user = webcam
       pass = xxxxxx
       dir  = public_html/images
       file = webcam.jpeg
       tmp  = uploading.jpeg
       passive = 1
       debug = 0
       auto = 0
       local = 0
       ssh = 0

       The annotation text is processed with strftime.  Check the strftime(3) or date(1)  manpage
       to  see  how  you can format the timestamps.  The text can also be read from a extern file
       (use  infofile  for  that).   The  default  color  for   the   text   overlay   is   white
       (RGB=255,255,255). Entries in the range of 0 through 255 for fg_red, fg_green, and fg_blue
       can be used to define a different color.  Likewise bg_red, bg_green, and  bg_blue  can  be
       used to set the background color (which defaults to transparent).

       input  is  the video source (TV/composite/whatever), norm the TV norm.  delay is the delay
       between two images in seconds.  wait is the  initial  delay  before  the  first  image  is
       grabbed  (some  cameras need some time for adapting to lightning, thus don't return images
       with reasonable quality within the first few seconds ...).  quality is  the  JPEG  quality
       for the stored images.

       top,  bottom,  left,  and  right  in the grab section allow cropping the image after it is
       grabbed.  They should satisfy 0<=top<bottom<=height and 0<=left<right<=width.  (0,0 is the
       top,  left  corner.)   If  rotate  is  positive, the output image will be rotated counter-
       clockwise 90 degrees that number of times (1, 2, or 3).

       With trigger set to a non-zero value webcam will upload the image only if the  content  of
       the image has changed.  It just looks for the maximum difference between the last uploaded
       and current image and if it is  greater  than  the  specified  value  the  image  will  be
       uploaded.  If once is set to 1 webcam will upload a single frame and quit.

       archive  can  be  used to create a (local) archive of the webcam images.  Just specify the
       filename for the files as argument.  The filename will be processed with  strftime(3),  so
       you  can  use  the  place  the  usual  time  format controls into the string to get unique
       filenames.  Non-existing directories are created if needed.

       If debug in the ftp section is set to 1 the complete communication between webcam and  the
       ftp  utility  is  printed  to stderr.  auto enables autologin via ~/.netrc (starts the ftp
       utility without the '-n' switch, check the  ftp(1)  man  page  for  more  info  about  the
       ~/.netrc  file).   If  local  in the ftp section is non-zero, files will be stored locally
       (using the dir, tmp, and file parameters) rather than ftped.  ssh set  to  non-zero  makes
       webcam use ssh instead of ftp.

CORRECTION OF DISTORTION

       contributed by Frederic Helin, the parameters belong into the [grab] section of the config
       file too.

       distor = 1
              If distor param is set to 1, the correction of distortion works.

       distor_k = 700
              This is the coefficient of  distortion.  This  algorithm  is  based  on  the  paper
              "Correcting  Distortion  of  Image  by Image Registration" of Toru Tamaki, Tsuyoshi
              Yamamura and Noboru Ahnishi. More your  lens  has  an  important  distortion,  more
              'distor_k'  must be neared of 0. 700 is the default value. Coefficient k of program
              is x100 than article.

       distor_cx = 192

       distor_cy = 144
              Coordinates of the lens optical axis: width/2 and height/2 are the default  values.
              The  axis  doesn't  go through the image center. So, you can change its coordinates
              around the center of image to affine correction.

       distor_zoom = 30
              Zoom parameter is used to cache the distorted borders of image, if you  don't  like
              this. Default value is 100.

       distor_sensorw = 320

       distor_sensorh = 240
              Dimensions  of  camera  sensor. Default values are for 1/4p sensor. This parameters
              used to have the same k coefficient than article.

AUTHOR

       Gerd Knorr <kraxel@bytesex.org>

COPYRIGHT

       Copyright (C) 1997-2002 Gerd Knorr
       This program is distributed in the hope that it will be useful, but WITHOUT ANY  WARRANTY;
       without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

                                     (c) 1998-2000 Gerd Knorr                           webcam(1)