H.265+ VIDEO SURVEILLANCE 4K H.265+ TAKES VIDEO SURVEILLANCE TO THE 4K ERA H.265+ INTRODUCTION AND BACKGROUND Recently, ultra-high-definition surveillance cameras introduced 4K resolution to the security industry. However, 4K resolution has yet to achieve wide application, mainly because of its tremendous bandwidth and data storage requirements. Limiting the bitrate of an ultra-HD video feed while retaining a high-quality, 4K image remains the biggest problem — a problem whose solution will decide the fate of ultra-HD surveillance videos. Video transmission balances image quality, transmission capabilities and data requirements — i.e., how much information and how it’s handled. Therefore, image transmission optimization lies in advancements in video compression technology. Until now, H.264 compression has been the industry-standard codec. When the H.264 codec found wide use, Hikvision Digital Technology developed its own compatible algorithm to go the next step, calling it “H.264+.” The next iteration in this codec lineage — H.265 — presently stands at the cusp of widespread adoption. And once again, Hikvision has already pushed this compression technology to a new level. H.265+ employs an intelligent algorithm whose encoding technology stems from the H.265/High Efficiency Video Coding (HEVC) standard. H.265+ optimizes the existing codec most strikingly where specific criteria are met in a surveillance video feed. This criteria consists of: 1) a stable background where information rarely changes; 2) a primary focus on the objects moving across that stagnant scene; 3) a substantial period of time where a scene’s moving objects appear only occasionally; and 4) 24-hour non-stop surveillance where visual noise has a relatively large impact on image quality. In this type of environment, field tests show H.265+ radically decreases the required bitrate of the ultra-high-definition surveillance video by up to 67 percent over H.265, thereby reducing required bandwidth and storage. Bitrate reduction means cost reduction for consumers, as well as increased efficiency, stability and reliability of all the hardware in a given surveillance system. Here’s how it works. THREE KEYS: ENCODING, NOISE AND BITRATES With ultra-HD resolutions and higher efficiency transmission as the two primary objectives, H.265+ improves the compression ratio based on three key technologies: 1) predictive encoding technology based on a background or reference frame; 2) digital noise suppression technology; and 3) long-term bitrate control technology. Predictive encoding Predictive encoding can be divided into “inter-frame prediction,” creating a prediction model from one or more previously encoded video frames, and “intra-frame prediction,” where the samples of a macroblock (processing unit) are predicted by using only information of previously transmitted macroblocks of the same frame. With inter-frame prediction, bitrates can be reduced by compressing only the difference in rates between a reference frame and any other frame. This reference frame — usually the background of a scene — will contain few, if any, moving objects. Fortunately, in most security surveillance, the background remains stagnant. Noise suppression In order to guarantee a high image quality of moving objects, the encoding module also encodes the visual noise in the scene. However, using the predictive encoding methods mentioned above, the H.265+ intelligent analysis algorithm distinguishes between the background image and moving objects so that each can be encoded with different encoding strategies. A background image is encoded with high compression in order to suppress noise and applies data to new or moving objects. Since data transmission is limited, the overall bitrate dips substantially when compared against conventional video compression. Long-term bitrate control Hikvision has introduced a concept it calls “Long-Term Average Bitrate” to make full use of a data from a video feed. Long-Term Average Bitrate calculates the rates over a specified time period (usually 24 hours). With the average bitrate control, the camera can assign higher bitrates to busier hours while reducing it during idle hours — e.g., midnight to 6 AM outdoors, or 8 PM to 7 AM in an office. In the case of a constant bitrate mode for H.265 encoding, the bitrate varies slightly but stays near the predefined maximum bitrate value. Using H.265+, average bitrate can be as low as half of the maximum bitrate. Image quality can still be optimized since the H.265+ technology makes full use of every bit.