  We present Dv2v, a new dynamic (one-pass) variable-to-variable compressor.
Variable-to-variable compression aims at using a modeler that gathers
variable-length input symbols and a variable-length statistical coder that
assigns shorter codewords to the more frequent symbols. In Dv2v, we process the
input text word-wise to gather variable-length symbols that can be either
terminals (new words) or non-terminals, subsequences of words seen before in
the input text. Those input symbols are set in a vocabulary that is kept sorted
by frequency. Therefore, those symbols can be easily encoded with dense codes.
Our Dv2v permits real-time transmission of data, i.e. compression/transmission
can begin as soon as data become available. Our experiments show that Dv2v is
able to overcome the compression ratios of the v2vDC, the state-of-the-art
semi-static variable-to-variable compressor, and to almost reach p7zip values.
It also draws a competitive performance at both compression and decompression.
