# Webcam32 - Frequently Asked Questions

This document contains the most frequently asked questions (FAQs) on the Webcam32 product:

- What cameras are supported by the Webcam32 server?
- What webcamcgi clients are available?
- Why does my picture not reload?
- Why do I sometimes get no image or a broken image with FTP?
- How can I get my image to automatically reload?
- Why does Webcam32 pause for many seconds before delivering a picture?
- Will Webcam32 ever become a full Web Server?
- Changing FTP target file permissions
- Can Webcam32 work with multiple cameras?
- Why does a Quickcam not correct for brightness?
- Where does the JPEG engine come from?
- Snappy Problems
- Using Webcam32 with AOL
- Why does Server Push not working with Internet Explorer?
- Port 80 is already in use message?

### What cameras are supported by the Webcam32 server?

Webcam32 has been tested with a greyscale Connectix Quickcam. The Webcam32 server used the Video For Windows system interface provided with Microsoft Win32 (Windows95/Windows NT). This should allow any VfW compliant camera to supply an image. See also the Webcam32 - working with cameras page.

### What webcamcgi clients are available?

A Windows 95/NT CGI client is supplied as well as Unix source code for a sample CGI. For more information on the Unix CGI program, please the Unix CGI Webcam32 page.

### Why does my picture not reload?

After creating a web page containing a link to a Webcam32 generated image, you find that the picture is static and that it is not refreshed when you refresh the page. Look at the HTML source of the page, you may find that if you have been using an HTML editor such as Netscape Navigator Gold, the reference to the Webcam32 server has been replaced by a locally saved one-off copy of a JPEG file. For example, if you had wanted the HTML to be:

    <IMG SRC="HTTP://myhost.mycompany.com:81">

you may find that you end up with

    <IMG SRC="SomeName.jpg">

The solution is to manually edit the HTML page and correct the HTML code. It is recommended that you add Webcam32 images by using the Insert HTML Tag option of your HTML editor.

### Why do I sometimes get no image or a broken image with FTP?

When using FTP to upload a new image, sometimes you may get a broken or missing image on your browser. This is because there is no file level locking when a Web server gets an image at the same time that an FTP server is changing the image. Although Webcam32 minimizes the risk by creating a temporary file and then renaming at the end to the target file, the rename action is not instantaneous. This error does not occur with either the CGI or HTTP protocols. This error has been seen only 1 in 1000 times.

### How can I get my image to automatically reload?

To have the Web page automatically reload the Webcam32 image, add the Refresh tag into your HTML source. An example of this is provided in the User's Guide.

### Why does Webcam32 pause for some seconds before delivering a picture?

There are two answers to this. Firstly, you may have configured your warning interval for sound an alarm and then pause for a few seconds before updating the picture. Select the warning dialog and examine the wait interval.
Second, you have a VERY slow nameserver. In which case, you should disable the Allow hostname lookup in the TCP/IP dialog.

### Will Webcam32 ever become a full Web Server?

I have no plans to even attempt to build yet-another Web server. Since Webcam32 can listen on any port number, its aim is to be an assister to a full-blow specialized Web Server.

### Changing FTP target file permissions

The FTP protocol does NOT allow file permissions to be changed from an FTP client. Thus Webcam32 is unable to change the file permissions created on a target file programmatically. This is not normally a problem as most FTP servers allow global file read of written files.

### Can Webcam32 control multiple cameras?

Currently, a single instance of Webcam32 can control one camera at a time. If multiple copies of Webcam32 are started, each instance can work with a unique camera. The camera to which Webcam32 attaches can be specified in the menu under File. With Webcam32 V4.4.0 and beyond, a unique profile may be selected for each Webcam32 instance.

### Why does a Quickcam not correct for brightness?

The Connectix Quickcam has a software video driver. When the preview screen of the Quickcam is not visible, the driver software supplied by Connectix is not invoked. This means that if the Quickcam is configured for auto-brightness, if the preview window is not shown the auto-brightening will not happen. The preview window is not visible if Webcam32 is minimized, obscured by another window or hidden by a screen saver or simply switched off. This is a known limitation of the Quickcam camera and there is nothing within Webcam32 that can currently assist. The solution is to ensure that the preview window is visible. Note: A technical solution was added to resolve this Quickcam limitation in Webcam32 V4.5.1.

### Where does the JPEG engine come from?

The JPEG encoding used by Webcam32 is achieved by the Independent JPEG Group (IJG) libjpeg libraries.

### Snappy Problems

Webcam32 requires that Snappy patches be applied. These patches are available from Play Inc. For more information on using Webcam32 with Snappy and the list of patches, see here. With the release of Snappy V3.0, Play, the makers of Snappy also changed the programming interface. As of today, Snappy V3.0 is not supported by Webcam32 but will be by year end.

### Using Webcam32 with AOL

There are some special instructions for using Webcam32 with AOL available here.

### Why does Server Push not work with Internet Explorer?

Server Push is a Netscape only feature. It has not been implemented by Microsoft in Internet Explorer.

### Port 80 is already in use message?

Webcam32 is shipped to listen on TCP/IP port number 80 on your local machine by default for incoming HTTP requests. This may change to a different default value in a future release. If you are running a Web server on your local machine, Webcam32 will complain that port 80 is already in use. Select a different TCP/IP port number in the TCP/IP settings within Webcam32 or else disable Webcam32 HTTP requests.

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Last updated: December 06, 1997