Video encoding and decoding using transforms

摘要

Video encoding or decoding utilizing a spatial transform operating on rows and columns of a block, with a set of transform skip modes including: transform on rows and columns; transform on rows only; transform on columns only; no transform. An indication of the selected mode is provided to the decoder. Coefficients are scaled by a factor dependent upon the norm of the transform vector of the skipped transform to bring the untransformed image values to the same level as transformed coefficients.

主权项

1. A method of video encoding in a processor utilizing a row transform operating on rows of a block of image values and having a row transform vector and a column transform operating on columns of the block of image values and having a column transform vector, comprising the steps of:
establishing a set of transform modes including a skip mode in which one or both of the row transform and the column transform are skipped; selecting one of the said modes; for any block where a transform is skipped, applying a scaling factor to the corresponding image values of that block, where the scaling factor is dependent upon the norm-2 of the transform vector of the skipped transform to bring the untransformed image values to the same level as transformed coefficients; and providing an indication of the selected mode for a decoder.