This invention introduces modification to a syntax signaled in slice segment header related to inter-layer prediction. A syntax optimization is proposed where if syntax element NumActiveRefLayerPics is equal to syntax element NumDirectRefLayers[nuh_layer_id] then the inter_layer_pred_idc[i] syntax elements are not signaled. In this case the value of inter_layer_pred_idc[i] syntax elements is inferred based on other syntax elements already signaled.