An Intra String Copy Approach for SCC in AVS3

An efficient SCC tool named Intra String Copy (ISC) has been proposed and adopted in AVS3 recently. ISC has two CU-level sub-modes: FPSP (fully-matching-string and partially-matching-string based string prediction) sub-mode and EUSP (equal-value-string, unit-basis-vector-string and unmatched-pixel-string based string prediction) sub-mode. Compared with the latest AVS3 reference software HPM with SCC tools disabled, using AVS3 SCC Common Test Condition and YUV test sequences in text and graphics with motion (TGM) and mixed content (MC) categories, the proposed tool achieves an average Y BD-rate reduction of 57.7%/39.5% and 77.2%/57.9% for TGM and MC in All Intra (AI)/Low Delay B(LDB) configurations, respectively, with low additional encoding complexity and almost the same decoding complexity.