Security Oxford

Video compression exists to facilitate the timely movement and efficient storage of image data. Without it, storage devices and communication systems would be swamped almost instatntly by the high amount of data in modern viedo footage. Consider HD Video compression on CCTV algorithms work in different ways, and whilst it’s not essential to understand the complex processing going on in the background, it does help to have some understanding of the techniqes in order to better appreciate the pros and the cons of compression. By appreciating why certain effects occur, you can better tune them out of systems.

The algorithms will capture a full frame of video, referred to as the I- Frame, and subsequent frames are then referenced against this to ascertain what change, if any, has occured. The algorithm then creates a frame containing only the change, the P-Frame, rebuilding the image with the remaining content of the I-Frame. It will continue to do this until a new I-Frame is captured. This time period can vary, but is usually around one second in CCTV devices.

Picture perfect?

Once a cornerstone of CCTV, JPEG- later followed by M-JPEG- compression were developed by the Joint Photographic Expert Group with the goal of efficient storage of individual photographic frames.