Copy memory blocks of different sizes
If it is possible that the strides match then you can add a if check to just copy it all in one go:

if(src_stride == dst_stride){
    memcpy(dst, src, count * dst_stride);
} else {
    while (count--) {
       memcpy(dst, src, dst_stride);
       src += src_stride;
       dst += dst_stride;
    }
}