NASA Logo
Skip all navigation and jump to content Jump to site navigation
Link to SVS Home Page Link to SVS Projects page Link to SVS Resources page Link to SVS Search page Link to SVS Sitemap

SVS Site Usage Requirements


Animation Pages

The basic element of our site is a page describing an individual animation.  In most cases, our animations are created at NTSC video resolution and frame rate, 720 pixels wide by 480 pixels high by 29.97 frames per second.  However, video pixels are not square, but are taller than they are wide, so the animations are meant to be viewed at a 4 to 3 aspect, or about 640 pixels wide by 480 pixels high.  Most animations are not yet available on this site in their full video resolution.  We are currently evaluating technical alternatives for the electronic distribution of full-resolution video.

The SVS does not fulfill requests for copies of the tapes in our library.  On some of our animation pages, there is a direct link to a video distribution service from which tapes including some of our animations may be ordered.  General information on this service can be found here.


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:

QuickTime - Windows, Macintosh

Movieplayer - SGI

Windows Media Player - Windows, Macintosh

Some animation pages also have QuickTime preview versions, which can be viewed with the QuickTime viewer referenced here.


High Definition Animations

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:

Visual Circuits HDfocus

Electrosonic HD Video Server

If you have a newer (i.e. faster) computer, we've found a few software players that can play many of these MPEG-2s at full resolution with reasonable fidelity. Two options we've used are:

VideoLAN which has players for Windows, MacOS X, and Linux.

MPlayer which is primarily Linux but has a MacOS X port available as well (http://mplayerosx.sourceforge.net/).


Images

Our animation pages usually display one or more small images in JPEG 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.

It is possible to use a program called curl to download multiple frames. Here is a quick tutorial on using curl to download frames from our site.

To download curl, go to http://curl.haxx.se/download.html.


Story Pages

Our site also contains story pages, pages created to support NASA media releases which included material created in the SVS.  Usually, these pages link directly to the animation pages supporting the story.