In response to the potential availability of high speed digital storage and transmission media with transfer rates of several Mbit/s or above, a new generation video coding standard is needed for high quality services. This paper summarizes the one year study carried out in ISO/IEC with collaboration of CCITT and CMTT, whose objective is to identify requirements for a generic video coding standard suitable for various applications such as storage and retrieval, communication and distribution. Necessary functionalities for respective category of applications are first identified, then storage and transmission media characteristics that may have an impact on the video source coding structure are extracted. Since a particularly important requirement for the new generation standard is to consider compatibilities with the existing standards, implementation methods are presented in detail. Finally, areas awaiting intensive technical study are discussed.