Two-dimensional transformation with minimum buffering

A method for transform with minimum buffering, comprising the steps of:

• (A) generating a sequence of intermediate matrices by multiplying a sequence of original matrices by a predetermined matrix;
• (B) writing said intermediate matrices into a memory in a first order that alternates between (i) a first of said intermediate matrices in a row order and (ii) a second of said intermediate matrices in a column order;
• (C) reading said sequence of said intermediate matrices from said memory in a second order that alternates between (i) said first intermediate matrix in said column order and (ii) said second intermediate matrix in said row order;
• and
• (D) generating a sequence of transform matrices by multiplying said intermediate matrices as read from said memory by another predetermined matrix.

An apparatus comprising:

• means for generating a sequence of intermediate matrices by multiplying a sequence of original matrices by a predetermined matrix;
• means for writing said intermediate matrices into a memory in a first order that alternates between (i) a first of said intermediate matrices in a row order and (ii) a second of said intermediate matrices in a column order;
• means for reading said sequence of said intermediate matrices from said memory in a second order that alternates between (i) said first intermediate matrix in said column order and (ii) said second intermediate matrix in said row order;
• and
• means for generating a sequence of transform matrices by multiplying said intermediate matrices as read from said memory by another predetermined matrix.