Padding=1 and "same" give different result

[ptrblck]

@ximing

Based on what I know, in the Conv2D, padding has two value: 0 and 1. 0 equals to “valid” which is no padding while 1 equals to “same” which means add 0 as padding and make the output size the same as input size.

That’s not generally true since the padding argument accepts different values and the “same” or “valid” option also depends on the kernel size, the stride, and other arguments.
In your use case you are using a kernel size of 1 which yields the same output size without any padding.