Databases Reference
In-Depth Information
Synchronization and presentation: The retrieval and presentation of
multimedia objects from an MM-DBMS bear some specific features
arising from the time-dependent features of most media types. For
instance, for a video clip to be presented properly, we need to ensure
adequate data throughput (i.e., 25 frames per second) so that the
presentation is continuous and of acceptable quality. This is a multi-
parameter issue involving several technological factors, such as com-
munication networks, secondary storage technology, compression
algorithms, and so on. Then, given that this issue (known as the
intramedia synchronization problem) is tackled, we have to take into
account the different synchronization relations among sets of
objects. The well-known example of a talking head requires that
the audio clip be in synchrony with the video clip so that lip syn-
chronization is achieved.
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Query languages, content-based retrieval, and indexing: Another
important issue related to retrieval is content-based retrieval, which
has attracted important research efforts and industrial interest.
Research has focused on content-based image indexing, that is, fast
retrieval of objects using their content characteristics (color, texture,
shape). For example, in [10] a system, called QBIC, that couples sev-
eral features from machine vision with fast indexing methods from
the DB area is proposed to support color-, shape-, and texture-
matching queries. Nearest-neighbor queries (based on image con-
tent) are addressed in [11]. In general, indexing of objects contents
is an active research area, while indexing of objects extends in the
spatiotemporal coordinate system sets a new direction. This chapter
presents the research efforts we have completed in the area of index-
ing and retrieval of IMDs based on their spatiotemporal struc-
tures [6].
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8.3.2.1 Retrieval of IMDs Based on the Spatiotemporal Structure
As mentioned previously, the retrieval of multimedia documents on the
basis of their spatiotemporal structure is a challenging theme. This chapter
presents the research effort we have completed in the area of indexing and
retrieval of IMDs based on their spatiotemporal structures [6]. During the
IMD development process, it can be expected (especially in the case of com-
plex and large applications) that the authors would need information related
to the spatiotemporal features of an IMD. The related queries, depending on
