It is widely accepted that the emerging concept of immersive media is one of the key technologies for future entertainment. One feature of immersive media is to use large panoramic screens with ultrahigh resolution. This technology requires a completely new production grammar that is not necessarily compatible with conventional production formats. Against this background the paper describes a new approach called format-agnostic production that bridges the gap between different target formats and applications. It does not use fixed numbers of frames, lines and pixels, or even geometry. The philosophy is to merge video signals from different camera sensors with different spatio-temporal resolutions and dynamic ranges to a wide-angle panoramic view of the scene. Hence, to support a wide range of applications from mobile devices to immersive media, any desired shot framing and resolution can be obtained by scanning, panning, or zooming. Apart from a general description of the concept and the system architecture, the paper will mainly focus on technical details of ultrahigh-resolution panoramic imaging which plays a central role in the concept of format-agnostic production.