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What is compression?
• Compression – Refers to reducing the quantity of data used to represent video images with the goal of retaining as much of the original’s quality as possible. • On the next few slides we will go over the different types of compression that are more prevalent in the CCTV industry.
Spatial vs. Temporal compression
• Compression techniques revolve around two basic concepts: Spatial compression and Temporal compression.
• Spatial Compression – Used on a single image as a completely independent entity with no relation to other frames, and removes data unuseful for describing the image. (JPEG)
• Temporal Compression
– Focuses on storing the changes between subsequent frames rather than the entire frame in isolation. If very little changes between subsequent frames then very little storage space is consumed. (MPEG)
• JPEG – An extremely popular spatial compression algorithm focusing on individual photographs or very low framerate video.