GNU/Linux man pages

Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :

ISBN : 978-2-7460-9712-4
EAN : 9782746097124
(Editions ENI)


CentOS 2.1AS







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


webcam [ config file ]


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


At startup webcam reads the configuration from the given config file or ~/.webcamrc if none is specified in the command line. It looks like this (the given values are the defaults):

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

device = /dev/video0
text = "webcam %Y-%m-%d %H:%M:%S"
infofile = filename
width = 320
height = 240
delay = 3
input = composite1
norm = pal
rotate = 0
top = 0
left = 0
bottom = -1
right = -1
quality = 75
trigger = 0
once = 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). input is the video source (TV/composite/whatever), norm the TV norm. delay is the delay between two images in seconds. quality is the JPEG quality for the stored images.

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). If local in the ftp section is non-zero, files will be stored locally (using the dir, tmp, and file parameters) rather than ftped.

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 a 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.


Gerd Knorr <kraxel@bytesex.org>


Copyright (C) 1997-2001 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.