readme

网络摄像头的webserver

Quickstart
==========

$ ./configure
$ make

Optional (you can try camsource without installing it):
# make install

Take a look at the included sample config file (camsource.conf.example).
It should be somewhat usable for experimental uses (although the
hardware section <camdev> may need tweaking), but you should change it
to suit your needs if you plan to use camsource. Put the config file in
a place where camsource can find it (such as .camsource in your home
dir, or /usr/local/etc/camsource.conf). The start camsource:

$ camsource

Or, if you didn't install it:

$ src/camsource

If camsource starts up without errors, it will go into background
automatically. Note that any errors from the grabbing thread show up
_after_ the logfile has been started, so you should check the logfile
for any errors (by default .camsource.log in your home dir). If
everything worked right and camsource shows up in your process list
(multiple time as it's multithreaded), feel free to try it
out. With the default config, point your browser to
<http://localhost:9192/> to see a 320x240 snapshot. The "/large" path
gives you an unresized snapshot. If the images appear mirrored, edit
your config and disable the "flip" module (it's enabled by default to
mirror all images).

With the default config, you have multiple options for getting an
animated webcam display:

http://host:9192/
http://host:9192/large
  Using a javascript html page, you can continually reload these images
  to get an animation. The "camserv" software includes such a javascript
  snippet (javascript.txt), see <http://cserv.sourceforge.net/>.

http://host:9192/multipart
http://host:9192/multipart-large
  These urls produce a multipart jpeg stream at a given fps. Netscape
  and mozilla can display and animate those without plugin (even though
  you may need to embed the url as image into a html page). This jpeg
  stream is compatible to what "camserv" produces (see above for url).
  To support multipart jpegs on other browsers such as ie, a java applet
  is required. Cambozola does an excellent job at this. See
  <http://www.charliemouse.com/code/cambozola/index.html>.

http://host:8888/
http://host:8889/
  These are pseudo-urls and not accessible through a browser. They
  produce an output compatible to "webcam_server," and the java applet
  included with webcam_server can be use to access these urls and
  animate the images. Note that even though webcam_server allows you to
  get a snapshot image when you point a browser at its url, the
  camsource module doesn't do this; point your browser at one of the
  other urls above instead. You can find webcam_server and the java
  applet at <http://donn.dyndns.org/portalofnnod/webcam_server.html>.

http://host:9192/largequal
  This is the unresized grabbed frame with a high jpeg compression
  quality (80). It is about twice the size of the default "/large"
  image. Use for your personal viewing pleasure or something.



Details (What is Camsource anyway?)
===================================

Camsource opens a video4linux device, grabs frames from it and does
various things with those frames. What it does with them depends solely
on the config file, which is in xml format.

Camsource uses plugins (also called modules) to provide functionality.
The plugin configuration happens through the xml config file. The core
camsource program, as well as the plugins, are heavily multithreaded, to
make sure different plugins don't interfere with each other, and with
the grabbing process.

Currently included plugins are:

wc_serv
  Produces output compatible with webcam_server. You can use its java
  applet to view the images.

http
  Generic http module, designed to answer requests by web browsers. It
  lets you define several virtual paths, each with distinct properties.
  Currently it is able to produce a single still image, as well as an
  animage multipart jpeg stream at a given framerate, usable on
  netscape/mozilla browsers or using a java applet such as Cambozola.
  Note that the paths you define can also include a query string such as
  "/image.jpg?large"; the requested url will always be matched exactly
  to the letter.

filewrite
  Periodically saves a snapshot image to a local jpeg file. 'Nuff said.

ftpup
  Works similar to the filewrite module, only that it uploads the snapshot
  to an ftp server instead of writing it out locally.

jpeg_comp
  This plugin doesn't do anything by itself, but provides jpeg
  compression functionality for various other modules. It will be
  auto-loaded as dependency, but you can give a default jpeg compression
  quality level for this module in the config file.

flip (filter)
  Lets you flip an image horizontally or vertically before doing
  anything else with it. Useful for cameras which produce mirrored
  images (such as my creative webcam 5).

resize (filter)
  Lets you scale an image to a specific size. Actually it doesn't
  "scale" much, it just does nearest-neighbor matching (read: bad
  quality). The filter lets you specify the target image size as a fixed
  width/height value pair, or as a percentage of the original image.

text (filter)
  This filter can add a text overlay containing a timestamp to an
  image. It has some special functionality with regards to the config
  file, which allow it to have a global config, and then override
  certain options in the per-module filter definition. See the
  example config file for details.
  The text to display can be set in the config file, or it can be
  read on demand from a file or from a command's stdout (pipe).

rgbbgr (filter)
  Swaps the red and blue information. Activate it in case your camera
  produces images with this reversed.

rotate (filter)
  This filter can rotate the image left or right by 90 degrees (or in
  other words, by 90 or 270 degrees). Rotating by 180 degrees is not
  supported, as the same result can be achieved by "flip"ping the image
  both horizontally and vertically. Keep in mind that after rotating,
  the image's width and height values will be swapped, so when you
  intend to use the rotate filter frequently together with the resize
  module, you should probably specify the final image size as a
  percentage (scale) instead of a fixed height/width pair.

bw (filter)
  Converts a color image into artistic grayscale / black & white.



The config file should be pretty self explanatory. Every possible
feature is present in the default config. Filters can be applied
globally (that is, to every grabbed frame), or on a per-module basis.
Note that the module is responsible for calling the filters, this
doesn't happen automatically. In the case of the http module, filters
can be applied to every frame handled by the http module, as well as on
a per-vpath basis.

Camsource looks in several places for its config file. First it looks
for it as ".camsource" in your home dir, then checks for a
camsource.conf file in /etc, /usr/local/etc and in the local dir. It
also looks for a "camsource" file in /etc/defaults and
/usr/local/etc/defaults. You can also specify a custom config file to
use on the command line.

The command line switch "-c" has been created to dump the video4linux
video capability information to console, then exit. Use this if you're
unsure about which frame sizes your camera supports. Optionally you can
specify another device file to open and query (defaults to /dev/video0).



Links
=====

Homepage: http://camsource.sf.net/


$Id: README,v 1.14 2002/10/02 16:43:09 dfx Exp $