查看文章

The compression or coding of a signal (eg, speech, text, image, video) has been a topic of great interest for a number of years. Numerous results and successful compression standards exist. Source compression is the enabling technology behind the multimedia revolution we are experiencing. The two primary applications for data compressing are storage and transmission. Video transmission is the topic of this chapter. Video transmission applications, such as on-demand video streaming, videotelephony, and videoconferencing, have gained increased popularity.

In a video communication system, the video is first compressed and then segmented into fixed or variable length packets and multiplexed with other types of data, such as audio. Unless a dedicated link that can provide a guaranteed quality of service (QoS) is available between the source and the destination, data bits or packets may be lost or corrupted, due to either traffic congestion or bit errors due to impairments of the physical channels. Such is the case, for example, with the current Internet and wireless networks. Due to its best effort design, the current Internet makes it difficult to provide the QoS, such as bandwidth, packet loss probability, and delay needed by video communication applications.