VidFIRE is the videoising process developed and trademarked by Peter Finklestone to restore the 'video look' to film recordings. For the first time, it has been possible to recreate the way that Doctor Who looked on its original transmission.
To understand the importance of VidFIRE, one needs to explain a little about the history of the older Doctor Who episodes. With only one exception, every Doctor Who story in the sixties and seventies was made using interlaced studio video cameras and generally recorded onto Quad videotape. Film was only used for location shoots.
However, all of the surviving episodes from the sixties and a good many from the early seventies now only exist as film recordings - literally video pictures transferred onto black and white film stock. Most of these recordings were on 16mm, made for overseas sales to countries which had yet to make the leap into colour broadcasting. Film was cheap, durable and free of the problems caused by incompatible video standards. A few episodes also exist as 35mm film recordings, usually because this was the way that they had been transmitted originally. This might happen for various reasons, including easy of editing film for complex sequences or because VT recording facilities were not available that day.
In interlaced studio video, each video frame consists of two video fields - one containing all the odd numbered lines, the other all the even numbered lines. Each field is captured 1/50th of a second from the last, so the position of any object moving through the fields changes fifty times per second. This gives a fluid, live 'video look' to the pictures, with a 'temporal resolution' of 1/50th of a second.
In contrast, film images are captured at intervals of 1/25th of a second, giving moving objects a jerkier characteristic, often referred to as the 'film look'. When interlaced video is transferred to a film recording, the two interlaced video fields, 1/50th of a second apart, are irrevocably imprinted onto one film frame. When this film is run, the original video look is lost, as the images now only update every 1/25th of a second. The original video look is replaced by the film look, with a temporal resolution of 1/25th of a second.
VidFIRE was developed to try to reverse this process - or at least to give the illusion that the process has been reversed. Using motion-estimation techniques, pairs of film frames are examined and the paths of moving objects in the frames is calculated. A new frame is estimated, midway in time between the two existing frames, using software that calculates where objects will have moved to 1/50th of a second after the first frame. By taking one video field from the real film frame and the second from the subsequent motion-estimated frame and interlacing them together, pictures with a temporal resolution of 1/50th of a second have been recreated and the 'video look' is re-established.
VidFIRE processing works hand in hand with our existing remastering techniques. Indeed, it is vital that the film recordings are cleaned up as much as possible prior to the application of VidFIRE in order that the illusion of videotape is not spoiled by the presence of film grain, dirt or sparkle. Because we are trying to achieve the look of the original transmission, those parts of the episode which were originally on film - ie titles, location inserts etc - are not VidFIRE processed, although there would be no technical reason why they could not be.
The results of the VidFIRE process were first seen on the VHS release of 'Planet of Giants' and the DVD release of 'The Aztecs'. A short VidFIRE sequence could also be found hidden away as an Easter Egg on the region 2 and region 4 DVD releases of 'The Tomb of the Cybermen'. VidFIRE made its broadcast debut on BBC2 at Christmas 2001, where it was applied to the two recently returned episodes of 'Dad's Army'. Since then it has been used to critical acclaim in the restoration of 'The Seeds of Death', 'The Dalek Invasion of Earth' and the 'Lost in Time' collection.
Copyright Steve Roberts, 23 August 2004