Spatial encoded video is used for a large number of mapping projects for various applications (McCarthy T., 1999). GPS data can be encoded onto the video or audio track using different techniques. One encoding/decoding hardware system, designed by Navtech (NavTech, 2007), enables 1 Hz GPS ASCII data strings to be encoded onto a single audio channel of any video recording format. Frequency shift keying modulation (FSK) (Miyagi M., 1968) techniques are used to encode GPS data stream onto audio stream during data acquisition. This GPS stream can be decoded using the same encoding hardware system during post processing whilst a frame-grabbing card is used to digitise single frames of video. Both image and GPS data streams are synchronised on GPS time and are saved to hard disk. These data-streams can be retrieved and analysed in a GIS for various mapping applications. Post processing of the data using frame-grabbing card has, to date, proved to be cumbersome and inefficient. This is due, for the most part, to the setup and operation of frame-grabbing cards. To overcome these limitations, a project was initiated with the key objective of simplifying this approach. This centred around development of a software decoder that can retrieve GPS data directly from the captured spatial video data files without the need for specialised hardware. An obvious advantage of this software algorithm is the ability to transfer audio video using any digital format, onto a PC desktop, using standard methods and systems. GPS can then be retrieved and displayed synchronised to the video stream using software, without the need for frame grabbing cards and cables.