Hi,
It is not supported in default deepstream-app. You have to modify the code and rebuild the application. The cpp file is
deepstream_sdk_v4.0_jetson\sources\apps\apps-common\src\deepstream_source_bin.c
Default source bin is
v4l2src ! videoconvert ! nvvideoconvert ! 'video/x-raw(memory:NVMM),format=NV12'
For MJPG source, it should be
v4l2src ! image/jpeg ! jpegdec ! videoconvert ! nvvideoconvert ! 'video/x-raw(memory:NVMM),format=NV12'