Hybrid video coding using variable size block transforms
Mathias Wien, Achim Dahlhoff · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2002
Adaptive Block Transforms (ABT) were recently proposed for inter coding in the emerging video coding standard H.26L. The basic idea of ABT is to connect the block size used for transform coding of the prediction error to the block size used for motion compensation. The maximum possible signal length is exploited for transform coding. In this paper, the concept variable block size transforms (VBST) is proposed for intra coding. The selection of the transform block sizes is based on a rate/distortion criterion. Several prediction modes including directional prediction are employed. In terms of PSNR the simulation results reveal better or at least comparable performance for the VBST coding scheme compared to the TML. A gain of about 0.5 dB can be observed for intra as well as for inter coding. The VBST scheme tends to preserve more detail information of the signal. Therefore, the subjective quality of the decoded video is generally increased.