The present disclosure relates to video coding.
Video coding finds use in many modern consumer electronic applications. Media players, such as media rendering applications, set top boxes and DVD players, commonly receive video data that has been coded by bandwidth compression techniques. The media players decode the video data before rendering it on a display. In other applications, videoconferencing applications perform bidirectional exchanges of coded video data. Each device codes video data representing locally-acquired video and transmits the coded video to another device. The other device receives and decodes the coded video, then renders it on a display.
Video coding and decoding processes typically are “lossy” processes. Video data recovered by decoders provides a representation of the source video from which it is derived but it possess various errors. When such errors are perceptible by human viewer, they often cause dissatisfaction with the viewing experience.
In many media exchange applications, different portions of a video may have very similar content. Consider, for example, a produced video where two characters are engaged in spoken dialogue with each other. Oftentimes, such events are represented by a video sequence that contains image information of a first speaker, then a second. Image content of the video sequence may toggle between image information of the two speakers for a time as the event progresses.
In many applications, video coders may apply different coding techniques at various points during such an event, which leads to different sets of artifacts. In the example above, a video coder may code image information of the first speaker differently during a first portion of spoken dialogue than during a second portion of dialogue, and the video coder may code representation of the first speaker differently during third, fourth, etc. portions as well. These different codings each may induce different sets of artifacts when the coded video data is decoded and rendered, which may lead to a dissatisfactory viewing experience.