Dirac is an open source video codec. It uses a traditional hybrid video
codec architecture, but with the wavelet transform instead of the usual
block transforms. Motion compensation uses overlapped blocks to reduce
block artefacts that would upset the transform coding stage.
Dirac can code just about any size of video, from streaming up to HD
and beyond, although certain presets are defined for different
applications and standards. These cover the parameters that need to be
set for the encoder to work, such as block sizes and temporal
prediction structures, which must otherwise be set by hand.