A method for adjusting a quantizer parameter (QP) value of a block of samples in a planar source picture that is input to an encoder for encoding may include identifying information associated with the planar source picture that is a projection of a non-planar surface. The method may include determining an initial QP value associated with the block of samples in the planar source picture. The method may include determining, based on the information associated with the planar source picture, a QP delta value associated with the block of samples. The method may include determining a final QP value associated with the block of samples based on the initial QP value and the QP delta value. The method may include coding the block of samples using the final QP value.