Info about... How the T2 high-definition film to digital master was made.

The previous transfer of T2 (the version that, appeared on T2 The Ultimate Edition DVD) was created at the highest quality available at that time. However, since that time, many improvements have taken place in the realm of film-to-video transfers (also known as telecine). Upon evaluation of the 1997 master elements, THX and Artisan determined that the picture Quality and format of the high-definition (HD) images might not meet today's standards for HD distribution in the future. While video processing on this older master could have created a good quality image for DVD, time and effort would be spent on a master that had little future. THX is proud to take part in Artisan's decision to retransfer T2 using the latest telecine and post production technologies. This new film transfer has resulted in the superior images you will find on this DVD release.

Starting from the same interpositive (IP) print created from the original negative of the film used in 1997, THX supervised the transfer of the film into HD video. This new HD master could be called an "electronic film master" since it is an exact representation of the film recorded onto HD-D5 videotapes. The transfer . and subsequent mastering were performed at International Video Conversions (IVC) in Burbank, California. .

The technical format for the T2 electronic film master is 1920x1080 24PsF. Here is a brief explanation of what that means. 1920x1080 is I the size of each video frame and is the current standard resolution of HD video. Each frame of the film is scanned into a frame of video that is 1,920 pixels wide and 1,080 lines high. Doing some math reveals that a picture size of 1920x1080 has an aspect ratio of 1.78:1 (1920 ÷ 1080) which means that the width of the picture is 1.78 times the height of the picture. 1.78: 1 is also known by the term 16x9 because 16 ÷ 9 also equals 1.78.

Any movie that has an aspect ratio of 1.78:1 would fill a 1920x1080 frame size perfectly. However, T2 was released in an aspect ratio of 2.35:1 which means that the width of the picture is 2.35 times the height of the picture. Movies that have an aspect ratio larger than 1.78 would have to have black mattes (also known as letterboxing) added to the top and bottom portions of the screen in order to fit the entire width of the wider film frame into a 1.78:1 picture as shown below.

For the left example, assuming that the heights of the boxes are the same, notice that a picture with an aspect ratio of 2.35 is wider than a picture that has an aspect ratio of 1.78. Therefore, in order to fit the width of a 2.35 frame into a 1.78 frame, empty space would appear at the top and bottom parts of the frame. These empty areas are filled with the black letterbox matte.

When a 2.35 feature is letterboxed in a 1.78 frame, only 815 lines out of a total 1080 lines are used for actual picture content. The rest is taken up by the letterboxing.

Because of letterboxing, in a frame size of 1920x1080, a 2.35:1 picture would have used, the entire resolution width of 1,920 pixels, but would only use approximately 815 lines of the 1,080 available lines. The rest of the 265 lines would be used and wasted by the black mattes. A decision was made early to optimize the new master by transferring the movie full frame by scanning each film frame so that it filled the entire 1920x1080 area, thus increasing the resolution of the image. While this master is not formatted properly, it utilizes every single line for the actual picture content and maximizes the ability to perform needed restoration.

In order to use every pixel and line available for the picture content, the film frames were scanned so that content filled the entire frame. However, note that the picture is stretched vertically (i.e. people look tall and "skinny").

24PsF (or Progressive Segmented Frames) describes two things: the frame rate and how the picture is created. The number "24" means that the electronic film master plays back at 24 frames-per-second, just like film. In fact, the electronic film master matches the film, frame for frame-one frame of film equates one frame of video.

"Progressive Segmented Frames" means that each frame of video is created progressively, just like film. In order to understand what progressive means, here are the differences between the two ways of creating video frames: progressive and interlaced. The majority of standard definition consumer televisions create frames of video using interlacing, while many HD consumer televisions are capable of creating video progressively.

With interlaced scanning the video frame is scanned as two separate fields, thus:

. Top field (odd scan lines) scan line numbers 1, 3, 5, 7, 9, 11, etc. followed by

. Bottom field (even scan lines) scan line numbers 2, 4, 6, 8,10, 12, etc.

. The video frame does not always capture the exact same content that a film frame contains

. Motion does not appear as smooth; diagonal lines are jagged

With progressive scanning the video frame is scanned in one complete pass thus:

. The complete video frame as: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12. etc.

. The video frame captures the exact same' content that a film frame contains at any instance of time

. Motion is smoother; diagonal lines are smooth

. Video frames are easier to work with since they are complete frames and not parts of frames

During the transfer, the film was colour-corrected and approved by James Cameron's production company Lightstorm Entertainment. The new master was digitally restored by removing dirt, scratches, and chemical stains using the latest in Digital Restoration Service (DRS) technologies. THX created a list of flaws from the master and the DRS computer artists highlighted all noted areas and digitally removed dirt and scratches to create a cleaned-up master. On average it takes 10 seconds to remove one piece of dirt in addition to the time needed to load and off -load the data to and from the hard drives. For these new masters of T2, the team performed a substantial number of hours of DRS. The services selected for the re-mastering of T2 allowed the superior image qualities of the movie to be retained and to maintain this quality throughout the post- production process without the need for post- processing of the image.

Because a special edition version on film of T2 never existed in its entirety, the special edition version had to be edited together from the theatrical version and the additional special edition scenes. The theatrical version of the film and the individual special edition scenes were all transferred and put through the DRS process using the above methods to 1920x1080 24PsF video. Because the HD version was similar to film in regards to being 24 frames per second progressive, editing the special edition version together was much easier than dealing with interlaced video masters.

The 24PsF format enables scenes to be added due to the 24-frame-per -second video rate. Prior HD formats were 3D-frame based which meant the film images were recorded with a 3:2 sequence in order to fit 24-frame- per-second film on a 30-frame-per-second video format. The 24PsF format allows seamless editing and  post production to take place without the 3:2 sequence, implementing this only after scenes are added. This produces a perfect 3:2 sequence integrity which is critical for the MPEG- 2 compression for DVD.

In addition to the special edition edit, two of the scenes in the special edition version were scene extensions to the theatrical shots. Because of the nature of the original film editing for the theatrical version, one frame was naturally missing between the theatrical shot and the extended shot for the special edition. The DVD producer, Van Ling,. recreated the missing frame from the before and after frames; these new frames were inserted into the special edition HD master to make a seamless transition between the original theatrical shot and the extended special edition scene.

The choices made in post production of the new master tapes provided a marked improvement over the 1997 masters. The new full-frame HD master can be used to create any other versions needed, in any frame rate or sizing: digital cinema masters used in theatres, HDTV broadcasts, or standard- definition masters for DVD. Subsequent conversions to full frame 16x9 and even 4x3pan- scan are simply a matter of applying a horizontal stretch to the full-frame image and performing the needed horizonta1 positioning necessary for these formats. Vertical resolution is left alone. A full-frame master is also perfect for any future digital cinema presentation as well. In the case of the T2 Extreme DVD the next step was to create the DVD masters.

THX supervised the creation of the new standard definition masters for the DVD release from the HD-D5 tapes (also called the down-conversion process). During this time, several experiments were performed to select the proper settings for the down-conversion image. After the settings were chosen, the feature was down-converted to create the proper aspect ratio for a standard definition 16x9, 2.35:1 master.

While the new transfer masters were being created, THX supervised a number of tasks to prepare the audio. The 24-bit 5.1 EX and stereo audio mixes were placed on both the theatrical and the special edition HD-D5 videotapes. The D5 tape format allows up to 8 discrete channels of 24-bit audio to reside along with the picture material.

The 5.1 EX audio was sent to POP Sound in Santa Monica, California, where the audio was compressed for DVD and reviewed by THX. Meanwhile, using the new down-converted masters, the video was compressed at DVCC in Universal City, California. Because the video compression for DVD strips away nearly 98% of the original bits used on the uncompressed DVD master, THX reviews every shot to verify that the compression matches the source as closely as possible in order to maintain the artistic intent and integrity of the film.

After DVCC finalized the programming of the navigation and features on the discs, THX, DVCC, and Van Ling scoured the disc data in a process called emulation. During the emulation stage, data that resembles the finished DVD is played back on a DVD emulator. The emulator acts like a set - top DVD player, but instead of playing data off a disc, the emulator plays back the data off a hard drive. The emulation stage reduces the cost and amount of time needed to create a DVD disc for test purposes.

After THX and Artisan approved the emulation stage, DVDs were created at Cinram USA in Huntsville, Alabama, and reviewed once again by THX, DVCC, Artisan, and Van Ling before being replicated, packaged and shipped to the distributors.

THX was present at every stage of the mastering and DVD process to ensure that quality was maintained throughout.

Please visit the THX website at www.thx.com/T2 for more details on the mastering and DVD process for T2.

THX Ltd. is the founder of quality assurance programs for superior cinema presentation. It was established in 1983 by George Lucas to ensure that the entertainment consumer experienced films as the director intended. Today, THX Certification assures the finest picture and sound quality for cinemas, mixing studios, home theatres, DVDs, multimedia products, and luxury automotive vehicles.

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