Question about gstreamer queue not working as intended with uridecodebin

[Ch'Ng Ming Shin]

Hi,

I have a question regarding gstreamer when an element runs slowly.

I have 4 uridecodebins  as sources (reading rtsp streams) and I link the pads to streammux, then I do
gst_link_many(nvstreammux, nvvidconv, queue, yolo_plugin, appsink, NULL);

To simulate a slow plugin, I sleep for 5 seconds in yolo_plugin whenever it receives a frame upstream. If I do not sleep, yolo_plugin will take 300ms to run. Despite having a queue, it does not give me the latest frame, but it gives me the next frame from the camera stream.

Can anyone help me to understand why is there no dropping of frames despite having a queue? I also noticed that rtspsrc in uridecodebin is only running once every 5seconds from the debug log, this seems very weird to me.

My desired outcome is that the uridecodebin will constantly decode the rtsp stream, and the queue will just drop the frames when yolo_plugin is running too slowly, but this is not the case. Can anyone help?

Regards,
Ming Shin
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