error C4146

[winsieutoc]

When i tried to build source code, I match a error:
error C4146: unary minus operator applied to unsigned type, result still unsigned
at return -(uint64_t)av_rescale_rnd(-std::max(a, -INT64_MAX), b, c, rnd ^ ((rnd >> 1) & 1));
How can I fix it?

Many thanks