Patent ID: 9578321
Date: 2017-02-21
CPC Classifications: H04N

Claim:
1. 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 utilizing a variable quantizer step size such that the encoded signal has a quantizer step size parameter associated therewith and utilizing 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 dependent on said quantizer step size parameter according to a predetermined relationship; b) generating a masking measure, the masking measure being dependent on the spatial complexity of at least part of the frames represented by the video signal in the decoded form according to a predetermined relationship; and c) generating a combined measure, the combined measure being dependent upon both the first measure and the masking measure according to a predetermined relationship; wherein the method also includes generating a second measure which is dependent on the prediction residual of the signal according to a predetermined relationship; identifying one or more regions of the picture for which the second measure exceeds a threshold; and wherein the masking measure is dependent on the spatial complexity of the identified one or more regions according to a predetermined relationship.