Hi,
For enabling smart record, currently we have document and the sample is undergoing. You would need to check the document and do the implementation.
For saving to JPG file, the samples in the links calls cv::imwrite(). In 5.0 GA, we have new functions in
deepstream-5.0\sources\includes\nvds_obj_encode.h
Samples:
deepstream-5.0\sources\apps\sample_apps\deepstream-image-meta-test
deepstream-5.0\sources\apps\sample_apps\deepstream-transfer-learning-app
Since samples are there and public, would encourage you take a look and do customization.