Motion Wavelet
Video signal compression algorithm

Currently the field of video information processing is experiencing a period of rapid development. The main motivating factors of video data compression algorithms development can be:

• Cost characteristics of the equipment;
• Availability of data storage systems volumes;
• Throughput capacity of digital communications;
• Estimation of movement parameters.

There is a significant amount of popular video signal compression algorithms present on the market; however they no longer meet the growing demands of security-market consumers. In fact the majority of the existing formats was created for a different type of consumer several years ago and present demands for compression/decompression and image quality cannot be applied to them.

Motion Wavelet is a compression algorithm developed by STREAM LABS for processing, transferring and storing video data especially for video surveillance systems. Instead of discrete cosine transform, typical for MPEG2, MPEG4, H.264 and JPEG, Motion Wavelet uses the method of wavelet transform. This allows to increase the detailing of registered data, maintaining the high image quality of each frame in video sequence, which is extremely important in security systems in contrast to nonprofessional home systems or digital TV systems.

The main advantages of Motion Wavelet algorithm include:

• Stable video on unstable channel
  If there is some problems with the link or a video frame is lost, the stream is not corrupted, as the calculation of the frame based not on the previous intra frame, but from the last key frame. If a problems with the link result a key frame will lost, a new key frame will be created;
• A highly effective intraframe compression;
• Interframe compression preserving the high quality of each frame of video recording;
• An option of scaling the image without extra computational power;
• Absence of blocks artifacts.

Highly effective intraframe compression

As a result of wavelet transform, the image turns out more even and precise and keyframe size is 25 % smaller than that of algorithms based on discrete cosine transform of identical quality.

Interframe compression preserving the high quality of video data

Motion Wavelet eliminates compression based on the psycho-visual perception model of a moving picture by a person, unlike MPEG2, MPEG4 and its numerous subsorts. This model feature is useful in increasing video data compression efficiency where viewing of «live» recording only is required, like in feature films on DVD-disks. However in video surveillance systems the important part of work is not the viewing of a moving picture, but frame-by-frame viewing or freeze-frame of video recordings, in case detailed analysis of events is required. The interframe compression method in Motion Wavelet allows to preserve equally high quality for keyframes and cut-ins.

Option of image scaling without application of mathematical algorithms

Wavelet-transform is performed by a method of image breakup into several layers similar to the JPEG progressive method of compression. However each layer carries comprehensive information, which allows video data to be viewed in smaller resolution. This algorithm property allows to adjust the load on digital data transfer channels and to eliminate the transmission of an excessive quality image to the automated work station operator.

Absence of blocks has an effect on a picture at a high degree of compression

Motion Wavelet it is completely free from the main drawback of its predecessors. Due to wavelet transform, the images in this format do not have the well-known 8 pixel block grid.