A novel scheme for extracting a JPEG image from an HEVC compressed video
Hyunjae Lee, Jongseok Lee, Dongkyu Lee, Seoung‐Jun Oh · 2017
In this paper, we propose a novel scheme for extracting a JPEG (Joint Picture Experts Group) snap shot image from an HEVC (High Efficiency Video Coding) bitstream. Since both JPEG and HEVC adopt the DCT-based transform coding scheme, we extract the DCT information from the HEVC bitstream and process the data to be suitable for JPEG compression. JPEG uses constant block size DCT whereas HEVC uses variable block sizes DCT. In order to unify the DCT block size, we use the direct splitting and merging in DCT domain. Then, we obtain the coefficients of the prediction frame by performing motion compensation in DCT domain. The coefficients of the current frame are reconstructed by adding the residual coefficients to the prediction coefficients. Then, the reconstructed coefficients are used for JPEG compression. The experimental results show that the proposed method comparatively well maintains the image quality with lower computational complexity.