[Duplicity-talk] controlling compression?

[Andreas Schuldei]

the duplicity manpage says:
      --no-encryption
                    Do not use GnuPG to encrypt files on remote
                    system.  Instead just write gzipped volumes.

this gives me the idea that backups are gzipped by default.
is this correct?

now i have a list of files (about half of my backup volume) which
is in formats which do not have a good compression ratio, like
jpgs or mp3s. i would like to be able to disable compression for
files matching a certain pattern, like *.jpg or *.bz2.
I wish those files were just encripted/stored as they are.

how can i do that?