The Dirac Algorithm
This document describes a prototype video
compression system based on motion-compensated wavelet coding.
The system incorporates tools for motion estimation and motion
compensation based on overlapped blocks to eliminate block
artefacts. Entropy coding is based on adaptive arithmetic
coding, and the reference coder is capable of trading off the bit rate of
different elements of the bitstream using Rate-Distortion
Optimisation techniques. The codec has not been very
extensively tested or optimised, but the performance to date
suggests that the codec is at least twice as efficient as MPEG-2.
This is a general description of the Dirac algorithm, and some details may
have changed since this was written. Refer to the Dirac
Specification for the
most up-to-date information.
Next: Table of Contents
This document refers to Version 0.9.1 of Dirac
Written by Thomas Davies, BBC R&D. Last revised 6 February 2008
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