Hi all, Sorry if this is the wrong place to ask questions about code written with the Python bindings... there doesn't seem to be a python-gst mailing list, so I figured I'd give this a shot. I'm new to gstreamer and trying to write some code that will slurp a stream off the web into a file, and transcode it to MP3 if not already in that format.  The application is to automatically convert it to a form that most portable audio players can understand. I have some working code, but not exactly sure "why" it works ;-)  Basically, what I do is I set up a gnomevfssrc ! typefind pipeline, and connect the have-type signal of the typefind element.  Then I start the pipeline playing.  When the have-type signal is received, I pause the pipeline, and then:   (a) if the detected stream is MP3, I make an identity element as the transcoder: transcoder = identity   (b) if it's not MP3, I make a real transcoder: transcoder = decodebin ! audioconvert ! lame Next, I link this transcoder to the end of the pipeline and link that to a filesink, so I end up with:   gnomevfssrc ! typefind ! transcoder ! filesink Finally, I unpause the pipeline, and the MP3 output stream magically goes into the output file.  Hooray! Here are a few things I'm trying to understand: * Are there any subtleties to modifying a running pipeline?  When I pause the pipeline, append to it, and then unpause it, should I be worried about data getting lost, or buffer overflows, or anything like that?  This doesn't seem to be a problem, but maybe I've just got lucky. * If I add() the transcoder and sink elements to the pipeline BEFORE I'm ready to actually link their pads, then the pipeline runs, and typefind works... but I get no output.  Why? * Typefind identifies MP3 files as application/id3 sometimes, rather than audio/mpeg.  Is there a more correct and reliable way to identify an MP3 stream? * How can I identify the duration of the stream processed by the pipeline?  pipeline.get_clock() seems to keep track of the REAL time, rather than the amount of audio processed. Any help will be appreciated!  Thanks a lot! Dan Lenski PS- The relevant parts of my code so far: class transcode_to_mp3(gst.Bin):     # a bin containing decodebin, audioconvert, and lame     # to auto-convert any audio stream to MP3     ... class StreamRecorder:     def __init__(self, uri, filename):         # stream reader         self.stream = gst.element_factory_make('gnomevfssrc')         self.stream.set_property('location', uri)         # automatically identify stream type         self.typefind = gst.element_factory_make('typefind')         self.typefind.set_property('minimum', 100)         self.typefind.connect('have-type', self.autoconfigure )         # convert arbitrary audio stream to MP3, or do nothing to an MP3         self.transcode = transcode_to_mp3()         self.identity = gst.element_factory_make('identity')         # write to file output         self.sink = gst.element_factory_make('filesink')         self.sink.set_property('location', filename)         # partially assemble pipeline         self.pipeline = gst.Pipeline()         self.pipeline.add(self.stream, self.typefind)         self.stream.link (self.typefind)     def autoconfigure(self, tf, prob, caps):         self.pipeline.set_state(gst.STATE_PAUSED)         ismp3 = (caps[0].get_name() == 'audio/mpeg' and caps[0]['layer']==3)         if ismp3: stage = self.identity         else: stage = self.mp3ify         self.pipeline.add(stage, self.sink)         gst.element_link_many (self.typefind, stage, self.sink)         self.pipeline.set_state(gst.STATE_PLAYING )     def start(self):         self.pipeline.set_state(gst.STATE_PLAYING)     def stop(self):         self.pipeline.set_state(gst.STATE_NULL)