| 摘要 |
A method of generating a measure of quality for a video signal representative of a plurality of frames, the video signal having: an original form; an encoded form in which the video signal has been encoded using a compression algorithm utilising a variable quantiser step size such that the encoded signal has a quantiser step size parameter associated therewith and utilising differential coding such that the encoded signal contains representations of the prediction residual of the signal; and a decoded form in which the encoded video signal has been at least in part reconverted to the original form, the method comprising: a) generating a first quality measure which is dependant on said quantiser step size parameter according to a predetermined relationship; b) generating a masking measure, the masking measure being dependant on the spatial complexity of at least part of the frames represented by the video signal in the decoded form according to a first predetermined relationship; and c) generating a combined measure, the combined measure being dependant upon both the first measure and the masking measure according to a predetermined relationship, wherein, the method also includes: generating an first measure which is dependant on the prediction residual of the signal according to a first predetermined relationship; and identifying one or more regions of the picture for which the first measure exceeds a threshold, wherein the masking measure is dependant on the spatial complexity of the identified region(s) according to a predetermined relationship; and further comprises: generating a background measure which is dependant on the prediction residual of the signal according to a second predetermined relationship; and identifying one or more other regions of the picture for which the background measure is below a threshold, wherein the masking measure is dependent on the spatial complexity of the identified other region(s) according to a predetermined relationship. |
