Video Compression

Fig. 1: Basic structure of a hybrid video encoder

Digital video compression is the enabling technology in many multi-media applications, as it reduces the bit-rate requirements for transmitting digital video and decreases delivery costs. With these appealing properties, digital video is rapidly becoming an experience of everyday life. For example, video telephony assists corporate and research users in a variety of collaborations utilizing the Public Switched Telephone Networks or the Internet. DVD players, High-Definition Television devices, digital camcorders, digital video recorders (DVR) and time-shifting products provide consumers with enhanced entertainment environments and novel methods for accessing media content. In the near future, wireless videophones promise un-tethered video communication between users.

Several compression standards are key to the success of digital video applications. These standards are targeted at different viewing and transmission environments and include ITU's H.261, H.263, H.263++ and H.264 as well as MPEG's MPEG-1, MPEG-2, MPEG-4 and MPEG-4AMD1. Most service providers and manufacturers prefer to develop and manufacture products that are compliant with one of these standards. However, it is important to realize that these standards are not bit exact, in that they only specify the decoder. Design of the encoder and development of efficient rate-control algorithms are specified by the manufacturer and are factors that distinguish one standard compliant product from another. The other crucial component that differentiates compression systems is the pre- and post-processing of the video sequence. Please feel free to look at the currently ongoing projects here at IVPL for more information.