pipeline problems - what am I missing?

[Gary Thomas]

I can run this command successfully:
    # gst-launch rtspsrc location=rtsp://some.server/url ! decodebin ! xvimagesink

However, when I try to code what I think is the equivalent pipeline in Python:
         player = gst.Pipeline("player")
         src = gst.element_factory_make("rtspsrc", "rtsp-src")
         src.connect("pad-added", src_pad_added)
         decode = gst.element_factory_make("decodebin", "decoder")
         decode.connect("pad-added", decode_pad_added)
         sink = gst.element_factory_make("xvimagesink", "image-sink")
         sink.connect("pad-added", sink_pad_added)
         player.add(src, decode, sink)
         gst.element_link_many(src, decode, sink)

it will fail like this:
   File "./client_monitor.py", line 71, in __init__
     gst.element_link_many(src, decode, sink)
   gst.LinkError: failed to link rtsp-src with decoder

Note that I added the 'pad-added' callbacks, but they are never called.

What am I missing here?  How can I get this pipeline built?

Thanks

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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