# Low-Level Video Features as Predictors of Consumer Engagement in Multimedia Advertisement
## 2 Related Work
### Video and Multimedia Content Descriptors
#### 2.2.1 Mpeg-7  
The MPEG-7 represents a well-established set of semantic and descriptive features that help manage, search, analyze, and understand modern multimedia content. Multimedia in the form of large numeric datasets poses a challenge to their interpretation due to the lack of efficient identification techniques that deal with large datasets at the specific level of content description defined by the context of a current application. A higher-level, yet generic set of media record descriptors that would reduce the size of the original content notation would be helpful. These descriptors can be determined manually or by automatic content analysis and preprocessing. The established MPEG7 [20; 21] standard addresses generic media record descriptors for indexing and searching multimedia databases, and has traditionally been used as a tool for indexing, searching, and accessing the desired multimedia content. MPEG-7 comprises a family of standards for multimedia content description and is defined by ISO / IEC 15938 [20]. Unlike its predecessors, the standard is not intended to encode audiovisual material but to describe it. Metadata about the material is stored in XML format and provides an accurate description that can be used to mark individual segments related to events in the material with a time code. This standard was developed to allow users to quickly and efficiently retrieve multimedia materials they need. It can be used independently of other MPEG standards and is closely related to the nature of the audiovisual material, as defined in MPEG-7. The MPEG-7 architecture states that multimedia content descriptions must be kept separate and the relationships between them must be unambiguously preserved. MPEG-7 is based on four basic building blocks: _Descriptors_ (metadata extracted from multimedia materials), _Description Schemes_ (structures and semantics of description relationships), _Description Definition Language (DDL)_ (a language that allows you to create and add new description schemas and descriptions), and _System Tools_ (tools that support description multiplexing, content synchronization, downloading, record encoding, and intellectual property protection). MPEG-7 contains 13 volumes, of which Part 3 contains tools for visual content description, namely, static images, videos, and 3D models. Descriptions of the visual features defined by the standard include color, texture, shape, and motion, as well as object localization and face recognition, each of which is multi-dimensional. Specifically, the core MPEG-7 visual descriptors are Color Layout, Color Structure, Dominant Color, Scalable Color (color), Edge Histogram, Homogeneous Texture, Texture Browsing (texture), Region-based Shape, Contour-based Shape (shape), Camera Motion, Parametric Motion, and Motion Activity (motion). Other descriptors represent structures for aggregation and localization and include core descriptor aggregates with additional semantic information. These include Scalable Color descriptions (Group-of-Frames/Group-of-Pictures), 3D mesh information (Shape 3D), object segmentation in subsequent frames (Motion Trajectory) and specific face extraction results (Face Recognition), Spatial 2D Coordinates, Grid Layout, RegionLocator, Time Series, Temporal Interpolation and Spatio-Temporal Locator. The remaining set of aggregated descriptors contains supplementary (textual) structures in color spaces, color quantization, and multiple 2D views of 3D objects. Some of these descriptors can be obtained using automated image analysis [22]. The visual features of MPEG-7 have relatively high dimensionality because each feature is a vector. Studies also demonstrated a high degree of redundancy in MPEG-7 visual features [23]. The MPEG-7 features are standardized, well-structured, computationally available, and provide a good basis for indexing, searching, and querying multimedia content. Some key computable features are represented in great detail (e.g., color and texture), whereas other media aesthetic elements are not directly covered.