Patent ID: 8689275

Claim:
A method of evaluating a profit of a substream of encoded video data, the video data comprising plural substreams of encoded video data, the substreams comprising different frame types and different partition types, the method comprising: separating the substream being evaluated into a plurality of data portions comprising at least some of the data in the substream being evaluated; comparing, for each data portion in turn, using a calculator, a decoded version of the video with the data portion present and a decoded version of the video with the data portion removed and calculating using the calculator an error metric indicative of a distortion between the two versions; and, averaging the error metric for the plural data portions; and, calculating a profit for the substream being evaluated dependent upon the averaged error metric, wherein the error metric is a peak signal to noise ratio, such that the profit of the substream having a frame type t and a partition type p is given by: P t , p = âˆ‘ r âˆˆ T t , p â¢ âˆ‘ f = 1 F â¢ ( PSNR f - PSNR f , r , p ) ï˜ƒ T t , p ï˜„ where PSNR f is the peak signal to noise ratio for a decoded frame f of the video, and PSNR f,r,p is the peak signal to noise ratio for frame f of the video missing a particular data portion having a frame type t and a partition type p, T t,p is a set containing the indexes of the frames of type t containing partition p, and F is the number of frames in the video.