Download MP4Box, which comes as part of GPAC. The only part of GPAC needed is MP4Box.
I wrote a little python script. If I drag and drop any number of .mp4 videos to it, _track1.mp4 audio files will be written out. (Adjust as necessary to point to MP4Box or change which track id to export).
import os,sys,subprocess def go(): for arg in sys.argv[1:]: print arg s = 'full/path/to/MP4Box.exe' if not arg.endswith('.mp4'): print 'must end with .mp4' return outfile = arg.replace('.mp4','_track1.mp4') assert not os.path.exists(outfile) scmd = '"%s" -single 1 "%s"'%(s,arg) # -single 1 means to extract track id 1 in an mp4 container. subprocess.call(scmd) go() os.system('pause')
If you want a full GUI (at the expense of bulk operations), Yamb looks like a candidate. It depends on MP4Box.