With the recent surge in popularity of digital video, the demand for video compression has increased dramatically. Video compression reduces the number of bits required to store and transmit digital media. Video data contains spatial and temporal redundancy, and these spatial and temporal similarities can be encoded by registering differences within a frame (spatial) and between frames (temporal). The hardware or software that performs compression is called a codec (coder/decoder). The codec is a device or software capable of performing encoding and decoding on a digital signal. As data-intensive digital video applications have become ubiquitous, so has the need for more efficient ways to encode signals. Thus, video compression has now become a central component in storage and communication technology.
Codecs are often used in many different technologies, such as videoconferencing, videoblogging and other streaming media applications, e.g. video podcasts. Typically, a videoconferencing or videoblogging system provides digital compression of audio and video streams in real-time. One of the problems with videoconferencing and videoblogging is that many participants suffer from appearance consciousness. The burden of presenting an acceptable on-screen appearance, however, is not an issue in audio-only communication.
Another problem videoconferencing and video blogging presents is that the compression of information can result in decreased video quality. The compression ratio is one of the most important factors in video conferencing because the higher the compression ratio, the faster the video conferencing information is transmitted. Unfortunately, with conventional video compression schemes, the higher the compression ratio, the lower the video quality. Often, compressed video streams result in poor images and poor sound quality.
In general, conventional video compression schemes suffer from a number of inefficiencies, which are manifested in the form of slow data communication speeds, large storage requirements, and disturbing perceptual effects. These impediments can impose serious problems to a variety of users who need to manipulate video data easily, efficiently, and without sacrificing quality, which is particularly important in light of the innate sensitivity people have to some forms of visual information.
In video compression, a number of critical factors are typically considered including: video quality and the bit rate, the computational complexity of the encoding and decoding algorithms, robustness to data losses and errors, and latency. As an increasing amount of video data surges across the Internet, not just to computers but also televisions, cell phones and other handheld devices, a technology that could significantly relieve congestion or improve quality represents a significant breakthrough.