• Characteristics of Video Data
  
  All existing database systems deal with alphanumeric data which uses a finite symbol set for description of an object. On the other hand video uses virtually infinite symbols during its productions process.
  

Characteristic	Video data	Alphanumeric data
Symbol Set	Inifinite	Finite
Resolution	High	Low
Interpretation Ambiguity	High	Low
Interpretation Efforts	High	Low
Data Volume	Large	Small
Similarity Measure	Ill difined	Well Defined

• Video Databases: What is needed?
  
  There two basic operations for very data management system:
  (1) suitable data structuring for its representation and organization;
  (2) data indexing and retrieval.
  
  Data Representation
  The spatio-temporal nature of the video data requires spacial attention. Video can be represented at multiple levels.
  

Level	Granularity	Descriptive features
Video	meta	concept, producer, director
Episode	macro	events description
Clip or Shot	mini	action, talk, goal
Frame	micro	object and its spatial relationship

• Video Data Indexing: content based and similarity based
  Videos --> smaller atomic units.
  Video clips + Label: future search and retrieval
  Video indexing: labeling video clips
  
  Content-based indexing: based on human psychology of remembering and recollecting information. e.g., People try to recall a person by their description such as tall, gray hair, blue eyes, long nose, etc.
  Implementation: Manual, Semiautomatic or fully automatic.
  
  Similarity-based indexing: an natural extensions to the image database's similarity retrieval research. Feature-based indexing is used in many indexing schemes.
  

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