Upon our thesis we were three computer engineers looking for a suitable project. Some brainstorming, a budget of of a few thousand euros for parts and 4 months later we stood ready with a working Instant Replay prototype. We combined our theoretical knowledge as civil engineers with our practical experience from broadcasting classes at the Luleå University of Technology to assemble and program a cheap, reliable and user-friendly device. The parts used for this prototype might not have been optimal nor adequate for a device used in professional productions. But it showed that a cheap, reliable and easy-to-use instant replay device could be achieved. All it took was a bit of time and ingenuity.

See our LGZ Replay for the improved and professional version of this prototype. It is now ready for demonstrations and has more tricks up its sleeve than the prototype. Keep tuned for more information!



  • 2 HD-SDI 720p50 inputs
  • 1 HD/SD-SDI (720p50 or 576i) output
  • 400GB storage and recording space allowing up to 15 hrs of material to be saved
  • A jogwheel and specially designed buttonset to control the device

We also designed and installed a protective backpanel on which all contacts were installed. The component cost stayed below 3000€. Considering price variations, added features, development costs and assembling costs we are still left with an comparatively cheap Instant Replay machine.


  • An easy-to-use user interface combining broadcasting standards with new user-friendly innovations
  • 3 visual clipbanks/playlists for the user to work with, which can hold several hundred clips each
  • A visual timeline on which the user can follow and control his workflow
  • All these components are gathered on one computer screen avoiding the use of several expensive monitors

Standardized yet innovative User-Interface

As in most Instant Replay machines we adopted the use of a jogwheel and programmable keyboard to browse aorund and work with the recorded material. That way users won't feel confused when later faced with a standardized control unit. What is different and new in our prototype is the grahical user-interface we've implemented.

All the necessary information is grouped and arranged on one screen. It consists of preview screens for the inputs and the output as well as a timeline guiding the users work. Along with a graphical representation of banks and playlists the interface becomes very user-friendly and almost self-explanatory. We believe this gives Instant Replay operators a good overview of what is going on and what they are currently doing.