This book constitutes the refereed proceedings of the 20th International Forum on Digital Multimedia Communication, IFTC 2023, held in Beijing, China, December 21-22, 2023. The 57 full papers included in this book were carefully reviewed and selected from 150 submissions. They were organized in topical sections as follows: CCIS 2066: Image Processing, Media Computing, Metaverse and Virtual Reality, and Multimedia Communication. CCIS 2067: Quality Assessment, Source Coding, and Application of AI.