Last Updated - 4 April 2005 17:59:15 gmt
This document contains the most frequently asked
questions (FAQs) on WebcamSat and Satcam products. If you don't find
an answer to your question, consider searching or asking on our live
Bulletin Board - WebcamSat
& Satcam
A: WebcamSat is Java-based server software that manages a collection of webcams. Satcam is Windows or Mac-based webcam software that captures images from a camera and sends them to WebcamSat. Note: WebcamSat and Satcam can both run on the same machine.
A: WebcamSat will run on any system that supports Java 1.4.1 or later, including Microsoft Windows, Mac OS-X, and Linux. You can download Java from http://java.sun.com.
You should have 50-100kbps of bandwidth available for each live camera feed viewer, and approximately 500k bytes of memory for each camera feed. WebcamSat does not use a lot of CPU power, so pretty much any modern processor should be adequate.A: The Windows version of Satcam uses Microsoft's "DirectShow" capture architecture, so you'll need a system that supports Microsoft DirectX version 8.1 or later. A reasonably fast processor - 400MHz or faster Pentium is recommended. The Mac OS-X version of Satcam uses Java and Quicktime. We don't yet have minimum system recommendations for the Mac.
A: Yes - In WebcamSat Version 2.0, support for Webcam32 as well as IP-addressable network cameras has been added. Note that Satcam may still be a better solution for the camera interface, as
A: Yes - since Satcam version 1.1, there's a file called scriptURL.txt in the main Satcam directory. Edit this file to include your server IP, port, feed ID and password, and the login will be automatic when you launch Satcam.
Note - Satcam's handling of this case is ambiguous. If scriptURL.txt contains a complete URL (without substitution values) this URL will be used without regard to the user's input in Satcam's dialog. In other words, clicking 'Connect' will cause your hard coded URL to be used. Anything entered in the text fields will be ignored. We plan to make this less confusing in a future release.
An alternate approach is to create a batch file or shortcut containing a reference to satcam-d.exe with your URL as its sole command line parameter, ie:
> satcam-d.exe http://123.123.123.123:8888/cgi-bin/wcs/get_script.cgi?id=1&pass=xxxx
A: We've tested Satcam with resolutions beyond 640x480 including a variety of DV cameras.
A: Once Satcam is running, look for the Satcam icon in the system tray. Right click on this icon, and you'll find a menu of camera features, including camera source selection, camera settings, camera capture resolution, and a preview window.
A: Currently, the best tool for tracking down Satcam issues is a debug monitor called "DebugView". You can download it from here. Eventually, we'll build error message logging into Satcam, but this tool does a nice job of logging.
A: WebcamSat has a full SQL database built in called Hypersonic SQL. This database can be externally accessed - a sample Java program called WstreamdDBSample.java is included with the WebcamSat distribution. It's now also possible to direct WebcamSat to access an external database.
A: Satcam is completely controlled by scripts that it downloads from WebcamSat upon login. You'll find tha actual scripts in script_templates subdirectory of your main WebcamSat installation. Take a look, for example, at the "video.wcs" script. Capture frame rate is set by "frequency =", image quality is set by "quality =" in the jpegenc filter definition, and image resolution is set in the videoscale filter definition. For more information on the Satcam modules and their parameters, see modules.html
A: On each camera feed, the WebcamSat administrator can specify access permissions for viewers. If a camera is set to allow "ALL" to view it, there are no access limitations. However, if the administrator creates a set of user accounts, and then defines which user accounts have access to which cameras, user name/password will be checked when viewers attempt to access the protected camera feeds.
A: Yes - we currently have a test version of a motion detection filter for Satcam called motiondetect.mdc. Details can be found here.
A: Yes - as of Satcam Version 1.1a, we added a feature called "on demand". Satcam checks with WebcamSat every few seconds to see if anyone wants to view its stream, and only sends video if there is an active viewer.
A: WebcamSat Version 2.0 has archiving support
built in, where capture is scheduled and saved to an AVI file. You can
capture and archive individual frames from any feed - the syntax in Linux
is:
shell_exec("wget --ignore-length -O /var/wcs/folder1/frame.jpg http://www.blah.com:8888/1.jpeg?frames=1");
where "1.jpeg" is the feed id in this example.
In addition, with
WebcamSat Version 2.0, we've added an archiving module to automate
this process.
A: Yes - like the example above for single frame
capture, you use the same syntax with addition of width and height
values:
shell_exec("wget --ignore-length -O /var/wcs/folder1/frame.jpg
http://www.blah.com:8888/1.jpeg?frames=1&width=xxx&height=yyy");
A: The problem is an implementation issue with the Sun's Java for Linux. The Sun Java VM process appears to be using a lot of CPU because of the way it is polling the sockets for data, but the Java process should be yielding to other processes on the system. The CPU load seems to be the same whether it's 1 stream or 100.
However, there is a solution ! There are several alternatives to Sun's implementation of Java on Linux, including optimized open source Java Virtual Machines as well as IBM JRE's, which comes with RH Advance Server. The specific one that's been most recommended is called "Blackdown", and can be downloaded from: http://www.blackdown.org/java-linux/mirrors.html
You'll need to download Blackdown version 1.4.1_01 of either j2re or j2sdk (j2re is probably all you need, unless you have a need to compile things)