Enhanced Use of Indexes

Researchers are investigating enhanced uses of index tracks, to aid both replay and search of media streams. When playback access to digitized audio streams is done from an arbitrary point the resulting sound is a comprehensible signal. However, this approach is not suitable for compressed digitized video.

For video, it is difficult to go to exact places as one can in a book for instance. Video is a continuous media without obvious demarcation points for the information, at present it is not possible to peruse a video in the same way as a book. There is no alternative but to watch large parts of the video by using the fast-forward and rewind buttons to skip to a certain place and then watch a section to determine if it is the correct one.

Researchers are designing some techniques that may be developed to improve the ability to find information in continuous media such as video. Existing work in this area uses just digitized video to extract information. Our approach is novel in that it uses compressed digitized video which has been stored in a multimedia storage system, such as the Video Conference Recorder, to extract the indexing information. We believe that it is possible to devise techniques for video that are equivalent to flicking through a book. This technique constructs a thumbnail video with just key frames presented. For example, one could show 1 seconds worth of frames for every 20 seconds or minute of real video. This will give a fast forward view of the video.

Techniques for encoding indexes into video have been devised at many places including MIT and Berkeley. These access digital video to create index information. Because multimedia conferencing and distance learning as a whole use data compression, it is pertinent to devise these new techniques which use the compressed video directly.

The techniques which will be developed here will help users search and peruse the online archives. If we compare finding information in a book with finding information in a video we see there are significant differences. A book is structured by separating information into chapters, sections, and paragraphs; a structuring which aids human comprehension and allows non-sequential access to the data. The book can be accessed one page at a time, or by going directly to a page which is the start of a chapter or a section. This is because a book is a collection of discrete sections. Further information about the book can be created by building indexes into the book which can be used to go to parts of the book which are about a subject in the index.

Once one can build indexes for the video, then the perusal of the stored video material can be readily used in various applications. One of the main applications for this kind of storage and indexing is in distance education in which compressed video and audio are heavily used. In distance education most of the remote classrooms and students do not have access to the raw video of the main classroom, they receive a compressed video stream which is stored for later use. It is expected that the students use the indexing information to scan existing video recordings in order to playback relevant parts of lectures and seminars. The indexes allow the student to access and peruse many hours of video rapidly in a similar way to perusing a book.