Last updated 7/9/98

Project Links Media Resource Page

Table of Contents:

General Media Restrictions
Graphics / Images
Video
Simulations: notes for Java and Shockwave developers
Animations
3D Visualization and Manipulation


General Media Restrictions

Restrictions In order to support the 640 x 480 and 800 x 600 resolution screens, there is a restriction on the max width/height of any media you put on your Project Links web pages.

Maximum height is 360 pixels
Maximum width is 500 pixels

A nice aspect ratio for the computer screen is 3:4. If you have the flexibility, stick with this ratio (e.g., 240 x 320, 360 x 480, ...)

Graphics / Images

Recommendations For Links images, we can use the formats which are supported by both Netscape and MS Internet Explorer. Currently, we are recommending GIF or JPEG formats based on the requirements of the image. Read the recommendation for each category in order to decide which format suits your particular needs.

You should use the format which suits your need but also produces the smallest possible file size in order to minimize the time it takes to download the image from the Links server.

There is a proposal for a new format, PNG (portable network graphics) which allows true color (24-bit) with an opacity channel. It is intended to replace GIF. See http://www.w3.org/pub/WWW/Graphics/PNG/Overview.html for information.

Palette Here is the links color palette (GIF) (PPM) derived from the colors in the logo. If you're looking for colors to use in an image, pick one from this set.
Max Dimensions Remember to keep images within 360 pixels height and 500 pixels width.
PNG Not yet on our recommended format list. This format still requires a plug-in with Netscape; IE provides partial support in a beta version in order to view these images.

Check out the PNG home page at http://www.wco.com/~png/png.html especially for image editors which allow you to create images in the PNG format.

GIF GIF is a format which allows a maximum of 256 colors and 1-bit transparency. In general, use the GIF format in these situations:
  • Your image requires transparency.
  • Your image is already an 8-bit image (256 colors).
  • Your image looks great as an 8-bit image.
  • Your image is a line drawing.
JPEG JPEG is a format suitable for realistic images such as photos. It is not suitable for line drawings. In general, use the JPEG format in these situations:
  • Your image is a photograph. The file size will generally be smaller and the image will have a higher quality than if you use the GIF format.
Royalty-Free Photo Sources
Hints To decrease image file sizes, try lowering the bit depth of your image. If you have an 8-bit (256 color) image, try lowering the bit depth and comparing the image quality. Depending on your image, you may not lose quality but the file size can drop significantly.

Video

Recommended Format QuickTime is the recommended format for video because a QuickTime plugin is commonly available for both Netscape Navigator and MS Internet Explorer on Windows and Macs. (Unix fans can try the xanim plugin.) There is a JavaScript function for you to put video on your web page. See the template module for details.

We evaluated MPEG, AVI and QuickTime video formats. All formats are currently available to some degree on the web (e.g., some require users to download plug-ins), but we recommend using QuickTime for now. The recommendation is based on the availability of production tools, viewing tools, as well as issues such as future Java support.

We recommend that you use the Cinepak codec for compressing video, because some of the others are not supported by the Java Media Framework. See the JMF site for details.

Royalty-Free Video Sources
Digitizing Video Tape at RPI There is at least one resource at RPI for digitizing video: the Sage Mac Lab (4th floor, Sage building). There are three machines which are connected by switchboard to these components: VTR, Hi-8, SVHS VCR. There are instructions near and on the machines for digitizing video. I believe there is also a contact person in case you need technical assistance.

Here are recommended technical specifications:

  • CODEC (compression): TBD
  • Frame Rate: TBD

Simulations

Recommended Formats Java and Shockwave are two recommended formats for building simulations. The reasoning is that Java and Shockwave fit into the technical requirements we're imposing on the end users. If you have another format you'd like to use, we'd like to know! Just be sure it fits into those technical requirements.
Max Dimensions Remember to keep the size within 360 pixels height and 500 pixels width.

Animations

Max Dimensions Remember to keep the size within 360 pixels height and 500 pixels width.
Recommended Formats Gif89a, Java, and Director/Shockwave
gif89a Gif animations are essentially a series of images which are stored within a single image file. The Gif89a format allows a builder to define pauses in the animation as well as place smaller images at exact locations within the larger image. These animations can be set to loop for a certain number of iterations. The animations are created using a tool such as The Gif Construction Set for Alchemy Mindworks.

Advantages

  • Low cpu overhead
  • Easily maintained (i.e., only a single file)

Disadvantages

  • File size can become large

Use this format for small, simple animations that are continually running. There is no user interaction mechanism, so users can't start, stop or rewind the animation. It's probably not useful for simulations or other advanced animations.

Java Applets Java applets can perform animations using either predefined images, or graphics primitives. Such animations can react to user actions, which offers a high degree of interactivity. As well animations can be based on a relatively high level of numerical computation done with the applet.

Advantages

  • Can be designed to be fully interactive
  • Use of primitives allows for extremely small file size
  • Creation can be done with free tools.

Disadvantages

  • Requires more experience than gif animations
  • More cpu overhead for user's machine
  • If using predefined images, file size can become quite large

Java animations are best used when they take advantage of the power of Java. For instance in simulations, or with high level of user interaction. For simple animations, Java involves too much overhead.

Director / Shockwave Shockwave is based on the highly popular Director software from Macromedia. Typically seen on the CD-Rom platform, these "movies" offer a high level of quality along with interactivity. Using the Director package, a developer produces a "movie" and then stores it in the Shockwave format.

Advantages

  • High quality graphics and speed
  • Can be designed to be fully interactive

Disadvantages

  • Shockwave viewer not available on UNIX platforms
  • High learning curve

Director's scripting language is probably less adept at numerical computation than Java, so if your animation requires this, try Java. However, for those Links developers who know Director, it is probably the best tool for creating animations.

If your animation is well-suited to using the QuickTime standard VCR-like controls (e.g., you only want the user to play, replay, stop, pause...), then it is recommended you use Director and export the movie to the QuickTime format.

3D Visualization and Manipulation

Recommended Format Java...
Max Dimensions Remember to keep images within 360 pixels height and 500 pixels width.

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