Hi,
We suggest you break down the pipeline to clarify where the leak is from.
rtspsrc location=rtsp://${usrname}:${pwd}@${ip}:${port}/cam/realmonitor?channel=1&subtype=0 protocols=tcp ! rtph264depay ! h264parse ! omxh264dec ! video/x-raw, format=NV12 ! fakesink
rtspsrc location=rtsp://${usrname}:${pwd}@${ip}:${port}/cam/realmonitor?channel=1&subtype=0 protocols=tcp ! rtph264depay ! h264parse ! avdec_h264 ! video/x-raw, format=NV12 ! fakesink
rtspsrc location=rtsp://${usrname}:${pwd}@${ip}:${port}/cam/realmonitor?channel=1&subtype=0 protocols=tcp ! rtph264depay ! fakesink
rtspsrc location=rtsp://${usrname}:${pwd}@${ip}:${port}/cam/realmonitor?channel=1&subtype=0 protocols=tcp ! fakesink