How did you make a lossless DTS-HD Master Audio soundtrack out of the 1983 70mm Magnetic Six Track Mix?
That’s the hairy_hen project (it’s a separate project from despecialized, synced to the same standard so that the audio is interchangeable and can be included with many preservations). IIRC this is a reconstruction of that six-channel mix using what we know of the four-track master, the matrixed Laserdisc stereo run through a dolby decoder, and some love (and some educated guesswork when it comes to the LFE). From what we can tell, it’s very close to the real thing. Then you just encode it in a slightly more home-video-friendly format (5.1) instead of the original 4.2.