se pool step calculation 
https://github.com/NVIDIA/NeMo/blob/256236f684cd08abd27008d6a9c41d77993be138/nemo/collections/asr/parts/submodules/jasper.py#L174

https://github.com/NVIDIA/NeMo/blob/256236f684cd08abd27008d6a9c41d77993be138/nemo/collections/asr/parts/submodules/jasper.py#L506

It seems that no matter what timesteps and context_window are, same formula is applied. 

By the way, suggesting to use `.to` instead of `.type`. [Reference](https://discuss.pytorch.org/t/why-does-pytorch-needs-the-three-functions-to-type-and-type-as/20164/2) 