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Composite Long-Term Reference Coding for Versatile Video Coding(VVC)

In this paper, a composite long-term reference picture coding algorithm for Versatile Video Coding (VVC) standard is proposed that can be used for the scenarios with large motionless area. In order to generate a high quality composite reference, a new generation method based on combined cost is adopted to compose the picture for long-term reference. After the generation of a composite long-term reference, VVC / High Efficiency Video Coding(HEVC) reference management high-level syntax is exploited to encode the reference as a no-display picture. Experiments are conducted under the common test condition in VVC and the results demonstrate that the proposed algorithm can achieve 2.55% bit-rate reduction on average with only 10% encoding time increase and negligible decoding time increase. For the certain sequence with large background area, e.g. BasketballDrill, the coding gain can be up to 13.47%. The proposed scheme was adopted by Joint Video Experts Team as an encoder coding tool for VVC standard under low delay configuration.