Probing the element UDP source when no data exists on the port.

vk_gst venkateshkuppan26 at
Wed Sep 19 12:05:13 UTC 2018

Hi James,

With the timeout, I can detect the loss of connection and take appropriate
actions. But once the connection is back, I am unable to resume the live
feed. The detection mechanism for the flow I used is adding probes on the
udpsrc, which does not work in my case.
For eg: my pipeline is a decoupled pipeline. 

Pipeline_src = udpsrc ! rtph264depay ! h264parse ! avdec_h264 !
Pipeline_sink = intervideosrc ! gltransformation ! glimagesink

When the timeout at udp source occurs, I pause the 'pipeline_src'(in the
callback function), because I need to apply gltransformation on the last
received video frame. This works perfectly fine, with the udpsrc timeout and
timeout callback. 

Now to detect, the flow of data through udpsrc, I installed a probe that
probes each BUFFER. But since the pipeline is in paused state, I think the
probes do not work when there is data again at the udpsrc. 

#psuedo code :
        # __init__(self):
        #add probe on UDP src
        self.mainsrc = self.pipeline_src.get_by_name('source')
        self.srcpad = self.mainsrc.get_static_pad('src')
        self.probeID = self.srcpad.add_probe(Gst.PadProbeType.PUSH,

    # udp source timeout callback
    def on_timeout(self, bus, msg):
            print("UDP timeout occured")

    #loop that applies gltansformation
    def apply_gl(self):
    #probe callback
    def probe_cb(self):

So is there a way to make the probes work even when the pipeline is PAUSED.
Or is there a workaround?


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