This paper presents a unified approach to coder control for video coding standards such as MPEG-2, H.263, MPEG-4, and H.264/AVC, using Lagrangian optimization techniques. The performance of these standards is compared in terms of PSNR and subjective testing results. The results indicate that H.264/AVC compliant encoders achieve similar reproduction quality as previous standards but typically require 60% or less of the bit rate. The paper also discusses the syntax features and decoders of each standard, and provides experimental results to demonstrate the effectiveness of the Lagrangian coder control method. The experiments are conducted for video streaming, videoconferencing, and entertainment-quality applications, showing significant bit-rate savings and improved rate-distortion performance for H.264/AVC compared to other standards.This paper presents a unified approach to coder control for video coding standards such as MPEG-2, H.263, MPEG-4, and H.264/AVC, using Lagrangian optimization techniques. The performance of these standards is compared in terms of PSNR and subjective testing results. The results indicate that H.264/AVC compliant encoders achieve similar reproduction quality as previous standards but typically require 60% or less of the bit rate. The paper also discusses the syntax features and decoders of each standard, and provides experimental results to demonstrate the effectiveness of the Lagrangian coder control method. The experiments are conducted for video streaming, videoconferencing, and entertainment-quality applications, showing significant bit-rate savings and improved rate-distortion performance for H.264/AVC compared to other standards.