In a particular implementation, a clipping bound may be different from the signal bound. For example, to derive the upper clipping bound, a reconstructed sample value corresponding to original sample value Y is estimated to be Y+Δy. Thus, for a candidate upper clipping bound x, the difference between the clipped value and the original value is calculated as min(Y+Δy, x)−Y. The distortions using different candidate clipping values around signal bound M may be tested. The test starts with signal bound M and moves towards smaller values. The distortion may first decrease (or maintain the same) and then increase, and the turning point is chosen as upper clipping bound M′. Similarly, the lower clipping bound m′ can be chosen. For more effective clipping, the color components may be transformed such that the transformed color components may be more tightly enclosed by a box defined by the clipping bounds.