DTS-HD MA and core DTS and how it works with MakeMKV

[PlumberOfDeath]

I'm a bit new to the process so if I go astray, please feel free to correct me.

My understanding of DTS-HD MA is that it can (and typically is) bundled with a core audio of simply DTS, that it can fall back to DTS with DTS-HD MA is not supported. In MakeMKV it appears as a nested track and that you can select each individually, allowing you to create a larger or smaller file. My confusion is in the result when both are selected. The resulting file is not a single audio track with both the DTS-HD MA and DTS but two tracks, one DTS-HD MA and the other DTS, between you must manually select. This does not appear to be the case with other remuxing processes.

Why is this the case?

Example:

MakeMKV where both DTS-HD MA and DTS are selected. When the DTS core 'subtrack' is not selected there is no Audio #2:

Code: Select all

Audio #1
ID                                       : 2
Format                                   : DTS
Format/Info                              : Digital Theater Systems
Format profile                           : MA / Core
Mode                                     : 16
Format settings, Endianness              : Big
Codec ID                                 : A_DTS
Duration                                 : 1h 34mn
Bit rate mode                            : Variable
Bit rate                                 : Unknown / 1 509 Kbps
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 24 bits
Compression mode                         : Lossless / Lossy
Title                                    : Surround 5.1
Language                                 : English
Default                                  : Yes
Forced                                   : No

Audio #2
ID                                       : 3
Format                                   : DTS
Format/Info                              : Digital Theater Systems
Mode                                     : 16
Format settings, Endianness              : Big
Codec ID                                 : A_DTS
Duration                                 : 1h 34mn
Bit rate mode                            : Constant
Bit rate                                 : 1 509 Kbps
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 24 bits
Compression mode                         : Lossy
Stream size                              : 1 016 MiB (5%)
Title                                    : Surround 5.1
Language                                 : English
Default                                  : No
Forced                                   : No

Non MakeMKV created remux (different source):

Code: Select all

Audio #1
ID                                       : 2
Format                                   : DTS
Format/Info                              : Digital Theater Systems
Format profile                           : MA / Core
Mode                                     : 16
Format settings, Endianness              : Big
Codec ID                                 : A_DTS
Duration                                 : 1h 31mn
Bit rate mode                            : Variable
Bit rate                                 : Unknown / 1 509 Kbps
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 16 bits
Compression mode                         : Lossless / Lossy
Title                                    : DTS-HD MA 5.1 / 48 kHz / 2259 kbps / 16-bit (DTS Core: 5.1 / 48 kHz / 1509 kbps / 16-bit)
Language                                 : English
Default                                  : Yes
Forced                                   : No 

[ndjamena]

You can't pass DTS-MA through SPDIF, so in some cases it may be necessary to have both the Core AND Master Audio in different streams for compatibility, the Core DTS stream will be duplicated in both tracks as the DTS-HD components cannot exist without its DTS core.