Predictive adaptive scan ordering for video coding

An apparatus comprising:

• an inverse scanning unit configured to generate a plurality of two dimensional (2D) arrays of quantized transform coefficients from the plurality of 1D strings according to a plurality of 2D scan order arrays;
• and an adaptive scan order predictor unit coupled to the entropy decoding unit and the inverse scanning unit, wherein the adaptive scan order predictor unit is configured to:
• provide the plurality of 2D scan order arrays that indicate different scanning patterns for the 2D arrays of quantized transform coefficients;
• maintain a plurality of absolute quantized coefficient summation matrices for the inter-prediction modes;
• and generate the 2D scan order arrays based on a descending order of the elements in the absolute quantized coefficient summation matrices, wherein the absolute quantized coefficient summation matrices comprise a plurality of cumulative absolute sums of the corresponding elements of the 2D arrays of quantized transform coefficients, and wherein the 2D scan order arrays comprise the indices of the elements of the absolute quantized coefficient summation matrices that are sorted in descending order.

A method comprising:

• acquiring a plurality of two dimensional (2D) arrays of quantized transform coefficients associated with a plurality of inter-prediction modes and/or a plurality of motion vectors for a first frame in a sequence of frames;
• initializing a plurality of absolute quantized transform coefficient matrices and a plurality of corresponding 2D scan order arrays for the inter-prediction modes and/or the motion vectors;
• acquiring a second plurality of 2D arrays of quantized transform coefficients associated with the same inter-prediction modes for a second frame in the sequence of frames;
• updating the absolute quantized transform coefficient matrices and the corresponding 2D scan order arrays for the inter-prediction modes and/or the motion vectors;
• and scanning the second 2D arrays of quantized transform coefficients of the second frame according to a plurality of corresponding predicted scanning pattern defined by the corresponding 2D scan order arrays, wherein the absolute quantized transform coefficient matrices are updated by adding the absolute values of the elements in the 2D arrays of quantized transform coefficients to the corresponding elements in the corresponding absolute quantized transfer coefficient matrices, and wherein the 2D scan order arrays are initialized by sorting the elements of the initialized absolute quantized transform coefficient matrices in descending order and storing the resulting ordered indices of the sorted elements in the corresponding 2D scan order arrays.