Why is the flag `GST_PAD_FLAG_EOS` set for element `v4l2src`, when the pipeline is modified dynamically?

vk_gst venkateshkuppan26 at gmail.com
Wed Sep 5 09:52:23 UTC 2018

Hi Antonio,

1. With the flushing event sent to the pipeline, the freeze-unfreeze
transition seems better as compared to previous idea of  setting the state
of complete pipeline to READY->PLAYING. 
However, with the flushing I observe that since the first transition from
freeze -> unfreeze, the rendering video displays a complete gray screen
(image attached) for a few seconds, before it starts displaying the live
video again. I think sending the flushing event, is introducing a delay in
at sink, which in turn renders the gray screen at the screen (code
I tried introducing a delay after the flush event, but that seems to be the
most inelegant way of doing when it comes to live video src. 
Is there another way to avoid this issue? 

2. With the output selector, I am still figuring out, the correct usage
since the switching of output is not possible yet. I always see a freezed
video on the rendering window. May be its just my implementation which I
need to correct. For eg: setting the pads, in the following way based on
user-input does not seem to work : 

#request pads
pad1 = op_selector.get_request_pad("src_%u") -- link to glimagesink (normal
pad2 = op_selector.get_request_pad("src_%u") -- link to

#based on user input activate one of the src pads
op_selector.set_property("active-pad",pad1) -- no user input or every second
user input
op_selector.set_property("active-pad",pad2) -- user input 

3. My final application will to have one of the following sources to receive
the video data packets.
- udpsrc 
- filesrc 
I am unsure if the same flushing event, will also work out in case of a
'udpsrc' . I would need to try this out as well. 

Code : 


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