do a search on gstreamer tools - i'm pretty sure it should be able to do it
I'm thinking allong th elines of a script that

# Create the player_name sink
player_name = gst.element_make_factory(“playbin”, “Multimedia Player”)
# Create the fake video sink
fake_video_sink = gst.element_make_factory(“fakesink”, “Fake sink for Videos”)
#Add the fake video sink to the player
player_name.set_property(“videosink”, fake_video_sink)
#Set the file
player_name.set_property(“uri”, “file:///home/peter/mymusic.mp3”)
#Set the State
player_name.set_state(gst.PLAYING)
#Play the file
.....
#After x seconds run gst.STATE_PAUSED or gst.STATE_NULL — Used to stop file
.......


Pretty sure you can use self.time_format = gst.Format(gst.FORMAT_TIME) to figure out where to start / stop too...