Preview Animations

Each animation page contains the entire animation in reduced resolution MPEG-1 format.  Why MPEG-1?  We needed to use a format with common viewers available for UNIX, Macintosh, and Windows systems.  This format had to have a high level of compression and still have enough resolution to show the animation clearly.  MPEG-1 satisfies these requirements.

There are two types of MPEG-1 formats used.  Many animations are digitized from the original video tapes at a resolution of 352 pixels wide by 240 pixels high by 29.97 frames per second.  Once again, these pixels are not square, and the animations should be viewed at a 4 to 3 aspect, or 320 pixels wide by 240 pixels high.  A compliant MPEG viewer should handle this aspect change transparently.  Some of our more recent animations are digitized from the original animation frames and use square pixels at a resolution of 320 pixels wide by 240 pixels high by 29.97 frames per second. 

Here are links to some of the more common MPEG-1 viewers we know about:

High Definition Animations (MPEG-2s and MPEG-4s)

Some of our animations are also included in a high definition MPEG-2 format.  As a rule, these animations are either 1920 x 1080 x 30 frames/sec or 1280 x 720 x 30 frames/sec, and cannot be played without specialized hardware decoders.  These animations are provided for specialized uses, such as museum displays or live presentations.  Here are links to several of the decoders for these formats:

Our animation pages usually display one or more small images in JPEG or PNG format that illustrate the content of the animation.  Larger images are called print resolution images and are provided in TIFF format for downloading.  Print resolution stills often have a size of 2560 pixels wide by 1920 pixels high, which is about 8.5 inches by 6.5 inches when printed at 300 dots per inch.

Warning: There is a generic problem with some TIFF files in that they can get reversed top-to-bottom if the display software is not completely compliant with TIFF specifications.  If you want to use a TIFF image from our site, please check that the image is being displayed correctly in your application, possibly by checking it with the smaller JPEG version of the image on our website.

Frames

Frames are accessible through the frames link on each animation detail page. We provide links to each file individually to allow for the greatest amount of flexibility for our users. Understandably, it is desirable to fetch more than one frame at a time.

There are currently two recommended tools for downloading multiple frames from our site.

Downloading Multiple Frames Using a Graphical User Interface (Firefox Plug-in)

NOTE: You need to use Mozilla's Firefox browser in order to use this plug-in. Firefox is available for Windows, Mac, and Linux operating systems.