Patent ID: 8150234
Filing Date: 2012-04-03
Classification: H04N

Abstract:
1. A method of evaluating a video signal comprising a plurality of video frames, the method comprising: (a) in the plurality video frames, analysing the number of pixels changed from one frame to the next; (b) identifying a frame as being a repeat if a set proportion of the pixels present in the current frame match those present in the previous frame; (c) recording a pattern of repeat frames in the video signal; (d) scanning the pattern to determine whether or not a given repeat frame is part of a temporally repetitive pattern; and generating an indicator of quality by identifying those repeat frames not determined to be part of the temporally repetitive pattern; (e) scanning the pattern by establishing a first window of multiple frames referenced in the pattern to a first frame and a second window of equal size in the pattern; (f) arranging the second window at an offset relative to the first window; (g) comparing the patterns of repeat frames in the first and second windows and recording the number of mismatches between the patterns; (h) repeating the comparison for each value of offset over range of offsets and recording the results; (i) selecting a new value of window size for the first and second windows, repeating the comparisons over the range of offset values and recording the results; and (j) determining a target window size that provides the least variation in mismatch values over the range of offset values.