Low computational cost improvements of the rate-distortion performance in MPEG-2 rate control

Abstract

Rate control in standards such as MPEG-2 or H263 plays an important role in controlling the compression rate and stabilizing the decoding and playback quality. In this paper, we combine the simplicity of the rate-distortion (R-D) predictive models with the improved R-D performance offered by the iterative approaches and we design effective rate control algorithms for low encoding delay and low complexity video compression. The proposed algorithms initially utilize the Lagrangian formulation in order to add a local R-D optimization component into the current rate control scheme of the standard. Subsequently, two online controllers are designed based on this local optimization scheme for adjusting the bit rate produced by the standard. Extensive experiments show improvements over the MPEG-2 scheme of 0.5–1 dB per frame for a variety of test sequences when the same target bit rates are maintained.