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For images, this step can be repeated by taking the difference to the top pixel, and then in videos, the difference to the pixel in the next frame can be taken.
A hierarchical version of this technique takes neighboring pairs of data points, stores their difference and sum, and on a higher level with lower resolution continues with the sums. This is called [[discrete wavelet transform]]. [[JPEG2000]] additionally uses data points from other pairs and multiplication factors to mix them into the difference. These factors must be integers, so that the result is an integer under all circumstances. So the values are increased, increasing file size, but the distribution of values could more be peaked. {{Citation needed|date=December 2007}} <!-- can someone please explain JPEG2000 for dummies!? Wavelets are fun if taken as continuous real valued function. But all this math for simple integer linear algebra? -->
The adaptive encoding uses the probabilities from the previous sample in sound encoding, from the left and upper pixel in image encoding, and additionally from the previous frame in video encoding. In the wavelet transformation, the probabilities are also passed through the hierarchy.<ref name="Unser" />
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