Entropy coders and 3D-Hadamard coefficients sequency scan order for a fast embedded color video codec

This work presents a new 3D-transform coefficients scan order based on the multiplication of the three dimensions sequency numbers of each coefficient. This scan process is developed to a fast embedded color video codec (also described in this article) to be executed in a set-top box on a fiber optics network. Due to its purpose, the codec is focused on reduced execution time, not on high compression rates. Low computational complexity and use of meager computational resources are also required. The Hadamard transform is used in a three-dimensional fashion, in order to avoid costly motion estimation and compensation techniques. The proposed scan procedure allows the coefficients reading in an idealistic “decreasing in the average” order. After the scan procedure, the encoding of the bits of the 3D-Hadamard coefficients is done, bit-plane-by-bit-plane, with an efficient adaptive version of Golomb's run-length encoder, which produces a fully embedded output bitstream. Even with the use of these constrained techniques, good distortion versus rate results were achieved.