Originally posted by: Vigo Hmmm, where did I hear these would be D1 master tapes... Another source claimed it would be D2 master tapes.
http://www.smr-home-theatre.org/frames.html?http://www.smr-home-theatre.org/THX/LucasFilm-THX.html
NTSC laserdiscs, videocassettes and DVD’s all fall under the mantle of THX Digital Mastering, a program started in 1993 – the first release being The Star Wars Trilogy on laserdisc. In the PAL format, only videocassettes are included, and these on a very small scale. Once again, Thomas Holman headed the project along with LucasFilm video engineer Dave Schnuelle.
The most important part of THX mastering is the video test signal. This is inserted into the space between each video field (the vertical interval) after the film has been converted to D-1 digital video tape. LucasFilm engineers only have an advisory role in this first stage – it is important that the image looks as the director intended. The video test signal allows constant monitoring of the black level, white level, chroma level, chroma noise, phase, frequency response etc., of the video signal throughout subsequent stages of reproduction.
The audio signal, be it Dolby Stereo, Dolby Digital, DTS or even monaural, is constantly assessed with the assistance of engineers from Dolby Laboratories or DTS to ensure consistent and accurate frequency response, phase, azimuth, and level. It must be stressed the THX software does not use a different sound format.
The audio and video elements come together on D-2 digital tape which is then converted to analogue in the case of laserdisc and videocassette (but not DVD) images, this is then used to master the final software. The THX test signal remains even in the final software and is again evaluated by LucasFilm engineers (who have the power to reject the entire inventory) at this stage.
http://www.rebelscum.com/gallery/swdeflaser/image6.asp...artifacts of the D2 (Digital videotape) intermediate format.