Carnegie Mellon University:
The Informedia Digital Video and Spoken Language Document Testbed

The Informedia collections

The Informedia Digital Video Library project is a research initiative at Carnegie Mellon University, funded by the NSF, DARPA, NASA and others, that studies how multimedia digital libraries can be established and used. Informedia's digital video library is populated by automatically encoding, segmenting, and indexing data. Research in the areas of speech recognition, image understanding, and natural language processing supports the automatic preparation of diverse media for full-content and knowledge based search and retrieval.

The following image is an example of how these components are combined in the Informedia user interface:

Currently, the Informedia collection contains approximately 1.5 terabytes of data, comprising 2,400 hours of video encoded in the MPEG 1 format. The content of this corpus includes approximately 2,000 hours of CNN news broadcasts beginning in 1996. The remaining content is derived from PBS broadcast documentaries produced by WQED, Pittsburgh, and documentaries for distance education produced by the BBC for the British Open University. The subject matter of the majority of these documentaries is mathematics and science. Also available is a small corpus of public domain videos, typically derived from government agency sources.

All the data in Informedia, except for the public domain videos, is copyrighted and must be used for research purposes only, with re-distribution prohibited. Users of the testbed will need to sign an agreement with the copyright holder.


The extensive, automatically derived metadata created by Informedia is an important resource for digital library researchers. Metadata for the Informedia collection includes:

  1. Transcripts - textual forms of the audio tracks derived from:

  2. Transcript alignment - Sphinx II derived transcript to video time alignment for all three forms of transcription.

  3. Video OCR - text regions identified and extracted from video imagery, converted to text via OCR.

  4. Face Descriptions - human faces detected in video, described by Eigen Face representations.

  5. Geocodes - latitude and longitude associated with video segments, derived from place names identified in the transcript and Video OCR data, computed from a gazetteer of world locations.

  6. Stills - representative bit map or JPEG images selected from every automatically identified shot break (change of camera view).

  7. Segments - video sequences representing single topic stories.

  8. Filmstrips - collections of stills representing a segment.

  9. Topics - automatically identified subjects of segments.

  10. Skims - automatically created video abstracts comprised of concatenated sub-sections of segments creating a shortened version of the video for previewing.

Further information

For general information about Informedia, see the web site:

Researchers with serious interests in using the testbed, should contact: Scott Stevens, [email protected].

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Copyright © 1999 Scott Stevens