An efficient near-optimal energy allocation method for multimedia data transmitted using multicarrier modulation is investigated in this research. Our algorithm allocates energy to carriers by solving a simple set of linear equations, which is near-optimal for almost the entire SNR range. Furthermore, based on the proposed energy allocation algorithm, we develop asymptotic limits for the approximation error, the carrier energy, and the carrier rate. While limits for the special case with uniform noise and BPSK modulation were obtained before, our derivation applies to the more general case with nonuniform noise and higher-order M-QAM constellations. Finally, we link these limits with several types of multimedia and non-multimedia sources.