Abstract: A method of encoding image data, including: frequency-transforming input image data to generate an array of frequency-transformed input image coefficients by a matrix-multiplication process, according to a maximum dynamic range of the transformed data and using transform matrices having a data precision; and selecting the maximum dynamic range and/or the data precision of the transform matrices according to the bit depth of the input image data.

Abstract: A method of image processing for image conversion, comprises the steps of calculating a difference measure of the difference in pixel values between corresponding blocks of a current image field and a preceding image field, calculating a variability measure of the variability of pixel values from at least one of said corresponding blocks, determining whether the difference measure exceeds the variability measure, and if the difference measure exceeds the variability measure, then setting an inter-image mixing value for each pixel in the corresponding block of the current image field to indicate that the current image field should not be mixed with the preceding image field at that pixel position.