Reducing error in a reconstructed frame is described. Pixels of the frame are classified into classes based on a classification scheme. Offset values for each class of at least some of the classes are determined, and a respective offset value for a class is applied to each pixel of the class, resulting in offset-adjusted pixels for the class. For the classes, a respective error rate reduction in using the respective offset value for a class as compared to omitting the respective offset value is determined, where the respective error rate reduction is based on the pixels of the class in the reconstructed frame, the offset-adjusted pixels of the class, and co-located source pixels in a source frame decoded to generate the reconstructed frame. A subset of classes is selected for reducing error in the reconstructed frame based on the error rate reductions.