C++ vector of vector slicing

Assuming I have a 2-dimension std::vector object representing a multi-channel data buffer.

std::vector<std::vector<int>> buffer = (2, std::vector<int>(512));

I would like to design a convolution filter function which takes a 2-D sliced data buffer as input. For example each slice is of size (2, 16).

/**
 * This is my current design.
 * I have to copy part of
 * my original buffer and return
 * a 2-D vector which I don't like
 */
std::vector<std::vector<int> convolve(std::vector<std::vector<int>> &sliceOfBuffer);

/**
 * I am looking for something similar to this
 */
void convolve(std::vector<std::vector<int>> &sliceOfBuffer);

For 1-D vector I can use 2 iterator to achieve the vector slicing. Is there any efficient way for 2-D vector as well?