How to custom preprocess in SGIE base on Deepstream 5.0?

I still need do some debug,but I just know How to modify gst nvinfer, first you need to read the info that bcao mentioned, then check the code:

and

the first one is preprocess for frame infer,the second one is for object infer.
all those function called a func named “convert_batch_and_push_to_input_thread” this func is used to do preprocess async.

pls read " DeepStream SDK FAQ" to understand some background info.