Blu-ray with DTS and DTS-HD MA

Not exactly encoding related but it fits here best I think. It's more just a general question. I have several Blu-rays here and they seem to contain a DTS and a DTS-HD MA track. What's the purpose of the DTS track? I thought if a device isn't HD MA compatible it would just switch to a "core track" within the HD MA track? So wouldn't the DTS track be redundant? Or is the DTS track I'm seeing actually the core track itself?

Is the DTS track stereo? I've seen that on a number of discs, multichannel core+HD, and a separate stereo track. Usually the core track is not exposed as its own stream, but I guess some tools may do that.

Are you sure it's not a commentary track? QB

There's no information about the disc to actually give an answer. There's multiple possibilities, but unless OP gives any more information like BDinfo read-out or a screenshot of the case, then there's nothing we can really do except give him an idea that may not be the actual answer. Let's presume the original language of the film is English. The main audio track would (most likely) be the lossless DTS-HD MA track. The other DTS (core) track could simply be a commentary, a different language, a special feature track (isolated score, perhaps (aka. "music only)), or even a different mix of the audio (maybe DTS-express 6.1, 4.0, 2.0?). I believe David Finchers's "The Game" (1997) has two separate audio tracks: one "near field" mix and one is "theatrical mix". But those two appear to be both lossless in format (). However, that was an example of the different types of specieal features the other track can be. I've seen several movies where the other DTS track is a core track and usually just a simple stereo mix or some other lesser feature (probably taken straight from the DVD-counterpart that featured the same DTS track). Feature tracks in a different language are often not in lossless, except when they are produced in their own country (a North American production of a movie with Engilsh as main track here would be lossless; while the same movie produced in France with a French translation track would have the French track in lossless while the English may or may not be the DTS-Core track --- However, since the original film is in English, it's likely to have English and French tracks in lossless in France distributions --- common sense on the various distributions concerning language tracks). Furthermore, what are you using to have all these tracks available? In some programs, like MakeMKV, when you insert a disc, while it shows the lossless DTS-HD MA track, it will alwasy show the option to use the DTS-core just underneath the lossless track, so that you can select either both the lossless track and lossy (as two separate audio streams: lossless audio track 1, lossy is audio track 2) or instead of (just the core if you don't want the lossless format). Why this is, is probably for those who have incompatible software that will read just the core only (streaming software/players that don't bitstream/passthru or utilize the dtsdecoderdll.dll in the likeness of LAV Audio Filters) and want to save space. Is there nothing on the case of the blu-ray movie that would indicate the madness of the second DTS track?