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.