Both methods RNAseq are transforming raw counts in a log2 scale using the
variance stabilizing transformation ("vst") or regularized logarithm ("rlog").
Both methods aim at removing the dependence of the variance on the mean.
Both methods include a normalization with respect to library size.

For details, see 

Love MI, Huber W, and Anders S (2014), Moderated estimation of fold change and dispersion for RNA-seq data with DESeq2. Genome biology, 15(12), 550.