Standard Designs for Cross Random Access Point Reference in Video Coding

In videos like movies and TV shows, similar scenes usually appear alternately. The period between these similar scenes is so long that it even exceeds the length of a random access (RA) segment. This means that the temporal correlation among these similar scenes crosses random access point (RAP). Besides, in videos like surveillance videos, a similar scene usually lasts for a long time which is longer than a RA segment. In other words, the temporal correlation among this scene also crosses RAP. To exploit the cross-RAP temporal correlation for further improving coding performance and keep the random access functionality at the same time, library picture based cross random access point reference is proposed and adopted in AVS3, which is going to be introduced in this paper. Firstly, a library picture is used as a reference picture for similar RA segments to exploit the temporal correlation among these RA segments. Secondly, to support random access, decoder and system layer are both designed to ensure that the decoder can get the corresponding library picture when random access occurs to correctly decode RA segments. Experimental results show that this method can save 6.4% and 31.5% BD-rate on the AVS3 general sequences and special sequences.