I would use FFprobe (it comes along with FFMPEG):
ffprobe -i INPUT -show_streams -select_streams a -loglevel error
In case there's no audio it ouputs nothing. If there is an audio stream then you get something like:
[STREAM]
index=0
codec_name=mp3
codec_long_name=MP3 (MPEG audio layer 3)
profile=unknown
codec_type=audio
codec_time_base=1/44100
etc
etc...
[/STREAM]
That should be easy enough to parse regardless of the language you're using to make this process automated.
