Gary Joseph Sullivan (born 1960) is an American electrical engineer who led the development of the AVC, HEVC, and VVC video coding standards and created the DirectX Video Acceleration (DXVA) API/DDI video decoding feature of the Microsoft Windows operating system. He is currently Director of Video Research and Standards at Dolby Laboratories and is the chair of ISO/IEC JTC 1/SC 29 (Coding of audio, picture, multimedia and hypermedia information – the committee that oversees JPEG and MPEG standardization) and of the ITU-T Video Coding Experts Group (VCEG).
He was the chairman and a co-founder of the Joint Video Team (JVT) standardization committee that developed the H.264/AVC standard, and he personally edited large portions of it. In January 2010, he became a founding co-chairman of the Joint Collaborative Team on Video Coding (JCT-VC) and an editor for developing the High Efficiency Video Coding (HEVC) standard. In October 2015, he became a founding co-chairman of the Joint Video Experts Team (JVET) that developed the Versatile Video Coding (VVC) standard. He has also led and contributed to a number of other video and image related standardization projects such as extensions of ITU-T H.263 video coding, multiview and 3D video coding for AVC and HEVC, and JPEG XR image coding. He has also published research work on various topics relating to video and image compression.