libaisdec is a library to decode ais packets as documented in ITU-R M.1371-4.

It requires the bdec decoder library (www.protocollogic.com).

https://github.com/asdf1011/bdec

The easiest way to install bdec is to use python's easy_install 
(https://pypi.python.org/pypi/setuptools#installation-instructions) application. 
Run: easy_install bdec


To decode an aivdm encoded file, run

   ./decode.py somefile.aivdm

To generate a c-language decoder / encoder, run

   mkdir output_dir
   bcompile -d output_dir --encoder spec/ais*.xml

Note that this will decode the binary representation, not the aivdm; to
convert aivdm to and from binary also compile the aivdm specification;

   bcompile -d output_dir --encoder spec/aivdm.xml

In code, populate the generated Aivdm structure (in aivdm.h) (one byte per
array entry), and call the encodeAivdm function to get the binary
representation. Pass this encoded buffer in the EncodedBuffer structure
to decodePacket in 'packet.h'.