eac3to is able to convert E-AC3, TrueHD, PCM and DTS-HD audio tracks to AC3, DTS or FLAC. Converts E-AC3, TrueHD, PCM, DTS-HD and FLAC tracks to AC3 / DTS / FLAC. Removes Dialog Normalization from AC3, E-AC3, DTS and TrueHD tracks. Extracts AC3 frames from Blu-Ray AC3/TrueHD tracks. Extracts DTS core from DTS-HD tracks. Can remux the video track of a EVO / VOB source to Matroska (mkv). Command line tool but GUI (UsEac3to) also available. Requires external audio decoders.
forum.doom9.org/showthread.php?t=125966
Alternative Graphical User Interface (GUI):
References:
en.m.wikibooks.org/wiki/Eac3to
en.m.wikibooks.org/wiki/Eac3to/How_to_Use