IMAGE OR VIDEO ENCODING AND DECODING

A method of encoding image or video content within a set of targets such as a time, a complexity, quality, and bitrate, using an encoder having a plurality of coding configurations, comprises setting an initial coding configuration in the encoder, where coding configurations differ one from the other in the number of options tested for each of one or more tools. A first part of the content is encoded in the initial configuration and measures are made of the number of times a specified tool is used and a representative time taken to test an option for that specified tool. From those measures a prediction is made of the time difference between the time taken to encode content using the initial coding configuration and the time taken to encode content using another coding configuration in which a different number of options are tested for that specified tool.