Hi,
The case is no supported:
... ! video/x-raw ! nvvidconv ! video/x-raw ! ...
Please run like:
... ! video/x-raw ! nvvidconv ! 'video/x-raw(memory:NVMM)' ! nvvidconv ! video/x-raw ! ...
You may customize nvv4l2camerasrc to have captured frames in video/x-raw(memory:NVMM) buffers directly. Please take a look at
Macrosilicon USB - #5 by DaneLLL