1. A method of decoding video from a bitstream of encoded video using a video decoder, the video including a picture partitioned into blocks, the method comprising: determining an activity rank for a block, based on a block size of the block and an intra-coding mode for the block; calculating a normalization value based on the activity rank divided by an average activity rank determined over a plurality of previously-decoded blocks; and dequantizing a set of decoded quantized coefficients for the block using a quantization step size adjusted by the normalization value.