Video retargeting refers to the process of changing the aspect ratio of a given video signal, e.g. from 16:9 to 4:3 or cinemascope to 16:9. With the growing diversity of terminal devices, such operations remain important in production and distribution. Simple operations like linear scaling, letter boxing or pan-scan cropping are often inacceptable as they cannot make use of the full display or do not handle the content faithfully. Instead, our system applies non-linear warping of the images in a content-adaptive way. Important areas (such as faces, salient objects) remain unchanged while stretching and squeezing is hidden in image areas, where it is less noticeable. Automatic image analysis extracts information from the video (e.g. saliency, edges). For offline production this can be combined with interactive user input. A constraint energy minimization results in a non-linear warping function to deform the images to the new aspect ratio in a content-adaptive way. Besides immediate application for video retargeting, this ground-breaking project laid the general foundation of know-how about non-linear, content-adaptive warping of images and video to change certain properties. In the next step, this was extended to stereoscopic 3D.