Would there be an advantage to copying data from managed stream to an intptr in blocks of 4096?

Question

In my libsndfile wrapper currently im using this. To read my stream (Must be a stream im loading from resource) But is this the best way i can fill the pointer with the requested data?

public static void ReadStream(Stream input,IntPtr output,int size)
{
    byte[] data = new byte[BufferSize];
    int i = BufferSize;
    int ptr_offset = 0;

    while (i == BufferSize || ptr_offset==size)
    {
        i = input.Read(data, 0, BufferSize);

        if (i + ptr_offset > size)
            i = size - ptr_offset;

        MarshalExt.Copy_MU(data, 0, output, ptr_offset, (uint)i);
        ptr_offset += i;
    }
}