One compelling application of the Informedia Digital Video Library is the indexing and retrieval of television, radio and text news. Currently, the TV and radio news is broadcast at a particular time, and if a person is not in front of a TV or radio at that time, the information becomes virtually inaccessible. Even if the news from different networks is taped on a VCR, there is rarely enough time to scan through tapes of yesterday's news for news stories relevant to a viewer's interest.
With traditional media, the viewer/listener must watch or listen to all stories in a news show, without the ability to select which stories to skip and which stories to pursue in more detail. Furthermore, a person can only attend to one news channel at a time. Similar or related information broadcast on another news channel at the same time cannot be viewed. In contrast, text news from newspapers and news-wire services or even from broadcast transcripts is available in overwhelming quantities but cannot provide the comprehensive visual and audio information available in the original radio and video material.
An MPEG-I encoded video of our system can be seen at
(size 51 902 501 bytes)
The solution offered by Informedia News-on-Demand is to compress and digitally store news broadcasts on computer. Each individual news story is indexed based on its transcript. The index links the words in the transcript to the sections of video/audio where the words occur. At the user's convenience, all news information becomes accessible through interactive queries, allowing the user to retrieve relevant news stories from all the networks and news sources that carried versions of the topic of interest.
One common attempt at a solution is to restrict the indexed data to text material. For example, most of today's news databases only store and retrieve the text characters of a news story. Even when broadcast news is indexed, only the transcript of the story can be retrieved, not the specific passage within the news broadcast video that is relevant to the query. On the other hand, video-on-demand only allows a user to select (and pay for) a complete program, but does not allow selective retrieval. The closest approximation to the News-on-Demand approach can be found in the "CNN-AT-WORK" system offered to businesses by a CNN/Intel cooperation. At the heart of the CNN-AT-WORK solution is a digitizer that encodes the video into INDEO format compression and transmits it to workstations over a local network. Users can, in principle, store headlines together with video clips and retrieve them at a later date. However, this service depends entirely on the separately transmitted "headlines" and does not include other news sources. In addition, CNN-AT-WORK does not feature an integrated multimodal query interface..
We can distinguish two distinct phases in the Informedia News-On-Demand process: library creation and library exploration. Library creation deals with the accumulation of information, transcription, segmentation and indexing. Library exploration concerns the interaction between the system and the user trying to retrieve selections in the database.