Very Low Bit Rate Video Coding – A Review

This paper presents a review of promising techniques for very low bit-rate, below 64 kb/s video coding. Video coding at such low rates will be a crucial technique in visual services, e.g., visual information transmission and storage. A typical application is to transmit moving videophone scenes through the existing analog telephone lines or via a mobile phone. Video compression techniques have to deal with data enriched by one more component which is the temporal coordinate. Compression techniques developed for still images can be either generalized for 3D signals, or a hybrid approach can be defined based on motion compensation. The video compression techniques can be classified into the following four classes: waveform, object based, model based and fractal coding based techniques. The aim of this paper is to provide an overview of these approaches as applied to low bit rate video coding algorithms.