Adaptive λ estimation in Lagrangian rate-distortion optimization for video coding

Abstract

In this paper, adaptive Lagrangian multiplier λ estimation in Larangian R-D optimization for video coding is presented that is based on the ρ-domain linear rate model and distortion model. It yields that λ is a function of rate, distortion and coding input statistics and can be written as λ(R, D, σ²) = β(ln(σ²/D) + δ)D/R + k₀, with β, δ and k₀ as coding constants, σ² is variance of prediction error input. λ(R, D, σ²) describes its ubiquitous relationship with coding statistics and coding input in hybrid video coding such as H.263, MPEG-2/4 and H.264/AVC. The lambda evaluation is de-coupled with quantization parameters. The proposed lambda estimation enables a fine encoder design and encoder control.