An apparatus includes processing circuitry that calculates, for each of a plurality of sign prediction hypotheses, a cost of the respective sign prediction hypothesis by performing sign prediction on a subset of a plurality of transform coefficients based on a subset of samples in at least one of a topmost row or a leftmost column of a current block. A number of samples in the subset of samples is a constant number and less than a total number of samples in the at least one of the topmost row or the leftmost column of the current block. The processing circuitry selects one of the plurality of sign prediction hypotheses with a minimal cost among the costs of the plurality of sign prediction hypotheses. Further, the processing circuitry coded the current block according to the selected sign prediction hypothesis.