The Video Coding Experts Group or Visual Coding Experts Group (VCEG, also known as Question 6) is a working group of the ITU Telecommunication Standardization Sector (ITU-T) concerned with standards for compression coding of video, images, audio signals, biomedical waveforms, and other signals. It is responsible for standardization of the "H.26x" line of video coding standards, the "T.8xx" line of image coding standards, and related technologies.

Administratively, VCEG is the informal name of Question 6 (Visual, audio and signal coding) of Working Party 3 (Audiovisual technologies and intelligent immersive applications) of ITU-T Study Group 16 (Multimedia and related digital technologies). Its abbreviated title is ITU-T Q.6/SG16, or more simply, ITU-T Q6/16.

The goal of VCEG is to produce ITU-T Recommendations (international standards) for video coding and image coding methods appropriate for conversational (e.g. videoconferencing and video telephony) and non-conversational (e.g., streaming, broadcast, file download, media storage/playback, or digital cinema) audio/visual services. This mandate concerns the maintenance and extension of existing video coding recommendations, and laying the ground for new recommendations using advanced techniques to significantly improve the trade-offs between bit rate, quality, delay, and algorithm complexity. Video coding standards are desired with sufficient flexibility to accommodate a diverse number of transport types (Internet, LAN, Mobile, ISDN, GSTN, H.222.0, NGN, etc.).

In 2023, VCEG began working toward standardization of coding technology for biomedical signals and other waveform signals.

Question 6 is part of Study Group 16, which is responsible for standards relating to multimedia service capabilities, and application capabilities (including those supported for next-generation networking). This encompasses multimedia terminals, systems (e.g., network signal processing equipment, multipoint conference units, gateways, gatekeepers, modems, and facsimile), protocols and signal processing (media coding).

VCEG was preceded in the ITU-T (which was called the CCITT at the time) by the "Specialists Group on Coding for Visual Telephony" chaired by Sakae Okubo (NTT) which developed H.261. The first meeting of this group was held December 11–14, 1984, in Tokyo, Japan. Okubo was also the ITU-T coordinator for developing the H.262/MPEG-2 Part 2 video coding standard and the requirements chairman in MPEG for the MPEG-2 set of standards.

The first digital video coding standard was H.120, created by the CCITT (now ITU-T) in 1984. H.120 was not usable in practice, as its performance was too poor. H.120 was based on differential pulse-code modulation (DPCM), which had relatively inefficient compression. During the late 1980s, a number of companies began experimenting with the much more efficient motion-compensated block transform hybrid compression model for video coding.

In 1994, Richard Shaphorst (Delta Information Systems) took over new video coding development in ITU-T with the launch of the project for developing H.324. Schaphorst appointed Karel Rijkse (KPN Research) to chair the development of the H.263 video coding standard as part of that project. In 1996, Schaphorst then appointed Gary Sullivan (PictureTel, 1999–2022 Microsoft, since 2023 Dolby) to launch the subsequent "H.263+" enhancement project, which was completed in 1998. In 1998, Sullivan was made rapporteur (chairman) of the question (group) for video coding in the ITU-T that is now called VCEG. After the H.263+ project, the group then completed an "H.263++" effort, produced H.263 Appendix III and H.263 Annex X, and launched the "H.26L" project with a call for proposals issued in January 1998 and a first draft design adopted in August 1999. In 2000, Thomas Wiegand (Fraunhofer HHI) was appointed as an associated rapporteur (vice-chairman) of VCEG. Sullivan and Wiegand led the H.26L project as it progressed to eventually become the H.264 standard after formation of a Joint Video Team (JVT) with MPEG in 2001, completing the first version of the standard in 2003. (In MPEG, the H.264 standard is known as MPEG-4 part 10.) After 2003, VCEG and the JVT developed several substantial extensions of H.264, produced H.271, and conducted exploration work toward the creation of a future new standard with better compression capability. Wiegand has remained an associated rapporteur of VCEG since that time.