Measuring received frame rate of rtsp video stream using gscam [closed]

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Hello,

I am transmitting video to a rtsp server using gscam. Here is the code for the gscam nodelet in the launch file:

<node pkg="nodelet" type="nodelet"
name="nodelet_manager" args="manager"
output="screen"/>

<node pkg="nodelet" type="nodelet"
name="$(arg cam_name)"
args="load gscam/GSCamNodelet nodelet_manager"
output="screen">

<param name="camera_name"          value="$(arg cam_name)"/>
<param name="camera_info_url"      value="$(arg camera_info_url)"/>
<param name="frame_id"             value="$(arg cam_name)"/>
<param name="sync_sink"            value="true" />
<param name="use_gst_timestamps"   value="true" />
<param name="gst_clock_type"       value="0" />    <!-- GST_CLOCK_TYPE_REALTIME -->
<param name="reopen_on_eof"        value="true" />

<!-- choose appropriate gstreamer pipeline -->
<param name="gscam_config"
value="gst-launch-1.0 rtspsrc location=$(arg rtsp_stream) latency=$(arg latency) ! decodebin ! videoconvert ! video/x-raw,format=RGB" />

<remap from="camera/image_raw" to="$(arg cam_name)/image_raw" />
</node>

Now, I would like to measure the received and dropped frame rate from the camera and there is a gstream element fpsdisplay for that. If I try this launch operation from console :gst-launch-1.0 rtspsrc location=rtsp://192.168.17.168:553/stream latency=400 ! decodebin ! videoconvert ! fpsdisplaysink, then it displays the frame rate on a pooped up window but if I want to use fpsdisplay in the pipeline in the above gscam nodelet in the launch file like this:

<param name="gscam_config"
value="gst-launch-1.0 rtspsrc location=$(arg rtsp_stream) latency=$(arg latency) ! fpsdisplaysink ! decodebin ! videoconvert ! 
video/x-raw,format=RGB" />

then it does not work, no topics are published. Through the documentations, I could not understand how to combine fpsdisplaysink in the gscam pipeline.

How then this element has to be combined with the pipeline?

Or if it is not clearly possible to get the received frame rate through fpsdisplaysink then how it can be done?

Thanks!