This disclosure describes rate control techniques that can improve video encoding. The described rate control techniques exploit relationships between the number of bits encoded per frame and the number of non-zero coefficients of the video blocks after quantization. The number of number of non-zero coefficients of the video blocks after quantization is referred to as rho (ρ). The value of ρ is generally proportional to the number of bits used in the video encoding. This disclosure utilizes a relationship between ρ and a quantization parameter (QP) in order to achieve rate controlled video encoding. More specifically, this disclosure exploits a parametric equation to map a value of a predicted ρ to a QP.