Because using the same number of bits per residual depth offset compression is not the best distribution of bits, the bits per residual may be distributed instead according to the content of the depths of a tile. For example, if the depth differences close to the Zmax are small, then fewer bits can be spent on residuals for the samples that are encoded relative to Zmax. Consequently, more bits can be spent on the residuals for the samples that are encoded relative to Zmin. As a result, more tiles succeed at compressing to the required number of bits.