OPTIMIZATION METHOD FOR ENCODING-BLOCK-LEVEL LAGRANGIAN MULTIPLIER OF EQUIRECTANGULAR IMAGE

The present invention relates to a method for video encoding, in particular to the technical field of encoding in a VR360 equirectangular video image format, and provides an optimization method for an encoding-block-level Lagrangian multiplier of an equirectangular image. In the method, a ratio ρ(θ) of the area of a spherical zone in which an encoding block is located to the area of a pixel zone of an equirectangular image in which the encoding block is located is calculated according to position information of the encoding block in the equirectangular image, optimization calculation is performed on λsys according to ρ(θ) to obtain an optimized Lagrangian multiplier λ(ρ(θ)), and the encoding block is encoded according to λ(ρ(θ)). The method introduces, in the form of an area ratio, position information of an encoding block into block-level correction and optimization of a Lagrangian multiplier, thereby significantly improving the overall performance of equirectangular image encoding. The method is adopted for