Perceptual difference evaluation of video alternatives in adaptive streaming

Adaptivity, which is the most important requirement for any video streaming systems, is usually supported by creating multiple versions of video content at the server. A practical question in this context would be “Which versions should be generated to support adaptivity?” For this purpose, we investigate, through subjective tests, the number of JND (Just Noticeable Difference) levels existing in the practical quality range of streaming video content. It is found that the typical number of video versions is 4 to 7, among which most versions are located in low bitrate range. The results of this study give useful insights for streaming content providers to prepare a reasonable set of video versions.