DTS-HD MA - Why are MA and Core both selectable ?

[SiliconKid]

I've read every post on the forum related to this and I haven't found any direct answer to my specific question yet.

What I'm not understanding is why it's even possible at all to select both the DTS-HD MA track and the Core DTS track contained within that MA track at the same time in MakeMKV and then produce an MKV file with both ?

It just seems to me that the MakeMKV UI should prevent selection of the Core track nested under the MA track IF the MA track is selected because the MA track will, by definition, contain the Core track, and anything that support DTS playback will know how to play only the Core track if it doesn't support full DTS-HD MA ?

As far as I can tell there is NEVER a reason to have a DTS-HD MA track and the DTS Core track both in the same MKV ?

With Dolby TrueHD I understand that a separate 5.1 Core track must be supplied in addition to the HD track because it is not wrapped like the DTS-HD MA tracks are. But with DTS-HD MA you do NOT need a supplementary 5.1 track for backward compatability.

It just really seems like a simple update to the MakeMKV UI could avoid a LOT of confusion in this regard.

I'm pretty well versed in these things and even I was initially unsure if I was doing the right thing by only selecting the DTS-HD MA track and NOT selecting the nested Core track.

The UI makes it look like you need to tick both in order to get everything you need for full HD MA, as if the top level tick box is only for the "extra" extension data that wraps around the Core, but if you do tick both it's actually redundant and you end up with the full HD MA track which contains the Core and then the Core as a separate audio track as well.

I'm fairly certain that it must be confusing to a lot of people.

I would expect the UI to gray out and lock the nested Core track, unticked, if I've already selected the full HD MA track.

I can understand that some people might ONLY want to select the Core, so it needs to be there nested, but if they opt to take the full HD MA, the Core checkbox should immediately untick and lock in the UI.

Am I missing something ? Or am I making sense ?

[SiliconKid]

To add some context to my confusion the image below might help.

As you can see, not only is there a DTS-HD track with a nested DTS 3/2+1 track, but there is also another DTS 3/2+1 track on the same level as he DTS-HD track, and they are all english !

For the uninitiated that is very confusing. I really wasn't sure what to select there.

And the thing is, if you select audio tracks you don't actually need it's not a trivial mistake in this case. Both of those Core tracks weigh in at around 1.5 GB each !

That means if you aren't sure what to select and select all 3 of those tracks, you will end up with around 3GB of extra audio tracks that you don't actually need.

[Romansh]

Some people only want the core (for e.g. file size considerations). I suppose it could be a toggle.

Regarding TrueHD, the TruehD and AC-3 substreams on Blu-ray are interleaved, but fully independent, it's not a core+extension architecture like DTS-HD.

[smashey]

The extra DTS core track (the one highlighted in blue in your pic) must a distinct track on that particular Bluray because I tested some of my discs and that does not show up.

I can not think of many reasons why someone would want both the DTS-HD track (containing the core) and also another core track in addition, so maybe a toggle would be better but I don't see it as being a big deal.

[SiliconKid]

For me, the primary source of confusion is around the nesting of the Core track as a tree node under the HD node.

On the face of it, because they can both be selected at the same time, it looks like there is some kind of relationship between them, and that you need to tick both to get the full HD track.

Maybe it's just because I'm a software developer by trade and build UIs myself and I'm being picky, but it genuinely confused me at first and when I ended up with an MKV that had 2 audio tracks in it I couldn't understand why at first.

The fact that both can be ticked together makes it seem like the upper level tick is only for the "Extension" part of the HD track.

The thing is, the way the UI currently works it makes you uncertain about what to do. You don't want to not tick the Core because you aren't sure if that's going to leave something behind that you actually want.

[SiliconKid]

"Regarding TrueHD, the TruehD and AC-3 substreams on Blu-ray are interleaved, but fully independent, it's not a core+extension architecture like DTS-HD."

@Romansh: That's an interesting one for me because I've always understood that with TrueHD the BluRay standard dictates that if a TrueHD track is supplied on the disc then another separate Dolby AC-3 5.1 "core" track must also be supplied as an additional audio track to supplement that because, as you rightly say, there is no "core+extension" methodology being employed like with DTS-HD, and the core track cannot be extracted from a TrueHD track and isolated like it can with DTS-HD.

From here: http://www.highdefdigest.com/news/show/ ... ained/1064

Level of support: TrueHD is an optional format on Blu-ray. And since TrueHD is not built in a core+extension configuration, Blu-ray discs that contain a TrueHD track are also required to contain a standard Dolby Digital AC-3 track for compatibility with players that don't support TrueHD.

[SiliconKid]

Regarding TrueHD, the TruehD and AC-3 substreams on Blu-ray are interleaved, but fully independent, it's not a core+extension architecture like DTS-HD.

@Romash:

This is an interesting point for me because I've always understood that if a TrueHD track is supplied on a BluRay disc then the standard dictates that another separate Dolby Ac-3 5.1 core track MUST also be supplied on the disc. There is no "core+extension" methodology employed as with DTS-HD, as you correctly pointed out, and therefore the core cannot be isolated from the TrueHD track.

From Wikipedia:

Regarding TrueHD, the TruehD and AC-3 substreams on Blu-ray are interleaved, but fully independent, it's not a core+extension architecture like DTS-HD.

From here: http://www.highdefdigest.com/news/show/ ... ained/1064

Level of support: Support for TrueHD up to at least 2 channels is mandatory on all HD DVD players, but the majority will support it all the way to 5.1. Because there are rare cases of disc players that limit TrueHD to 2 channels (such as the LG model BH100), discs with TrueHD tracks must also contain a Dolby Digital Plus track for 5.1 compatibility.

[necrosis]

It was my understanding that with DTS-HD MA the core track MUST be selected because DTS-HD MA is only the audio data dropped after converting to lossy DTS.

Where as with TrueHD (very uncommon from what I have seen when backing up my BluRay collection) is the full audio track so you can drop the core audio if you don't want it (but lose 'backwards compatibility' if your receiver does not support it [bitstreaming] or your player can't downmix).

[mike admin]

Two notes, guys.

1. There are two ways to encode DTS HD MA stream - with core (HD stream encodes residue) or without core (HD stream encodes everything). I've never seen a no-core stream on blu-ray though.

2. Each checkbox in UI represents a stream. The confusion comes from the excellent backward compatibility of DTS HD MA - if core is present (and it is almost always present) then most players recognize and play it properly.

[Chetwood]

See these:

http://www.avsforum.com/t/1415816/makem ... t_22149727

http://forum.doom9.org/showthread.php?p ... ost1415246

[Romansh]

Two notes, guys.

1. There are two ways to encode DTS HD MA stream - with core (HD stream encodes residue) or without core (HD stream encodes everything). I've never seen a no-core stream on blu-ray though.

DTS-HD audio stream: A DTS-HD audio stream consists of two sub-streams; one Core sub-stream and one Extension sub-stream.

Just like BD mandates the AC-3 audio track

[SiliconKid]

@Mike Admin: I'm still unclear on what the correct procedure is in terms of the MakeMKV UI.

For DTS-MA, where the UI shows 2 tick boxes with the Core stream nested under the MA stream, do we need to tick BOTH boxes if we want full DTS-MA ?

If we only tick the top level MA box and leave the Core checkbox, what happens then ?

Your comment about there being 2 ways to encode DTS-MA has now confused me even more

It seems fairly clear that if I ONLY tick the Core checkbox I will get the Lossy DTS Core 5.1 track and that's it, but I'm still unclear as to whether I need to tick both checkboxes if I want full DTS-MA.

Please clarify and explain the specific relationship between those 2 checkboxes.

Thanks

[NodNarb012]

You only need to check the DTS-HD stream; it will automatically take the DTS core and DTS-HD extension to give you the full DTS-HD experience you're after.

I have tested this; my PopcornHour C-200 plays it as DTS-HD while my WDTV Live extracts and plays the DTS core since it doesn't support DTS-HD.

If you check both boxes, the first audio track will be the full DTS-HD core+extension and the second track will be just the DTS core. As long as all of your devices can playback the full DTS-HD track or at least extract the DTS core from that same track, then there is no reason to select the box for the DTS core.

[joe42]

I believe the confusion arises because MakeMKV will never create an MKV stream with just the "residue" which makes up the difference between the lossy core DTS track and the full lossless DTS-MA audio track. I guess (but don't know) that the reason MakeMKV will not create such a stream is that it is either specifically not allowed in MKV, or else it is not well-supported in MKV.

Since MakeMKV will only create "complete" MKV streams, then there are two possible streams it can create from the core and residue parts of the DTS/DTS-MA track: a complete lossy core stream, or a complete lossless stream. The top/outer checkbox generates the complete lossless stream, and the bottom/inner checkbox generates the (complete) core stream. Note that you can select neither, either, or both, so your MKV can include none of those streams, just the core, just the lossless, or both.

Clearly it is necessary to have two checkboxes in order to account for all 2 x 2 = 4 of those possibilities. However, it is not clear that the core track should be shown graphically as a child of the lossless track, since from the user's point of view, that is irrelevant. MakeMKV needs to know the relationship so it can generate the complete lossless stream, but all the user needs to know is that it is a core DTS 3/2+1 stream or a DTS-MA lossless stream.

Just as you were, I was confused by the way MakeMKV graphically represents the relationship of the streams. I think it would be less confusing if MakeMKV did not show the core stream as a child of the lossless stream. MakeMKV should just show the core stream at the same level as the other audio streams. Except the label needs to have "Core" added to it ("DTS 3/2+1 Core English") so that the user knows it is a core stream and not just an alternate DTS 3/2+1 stream (as in the example you posted here).

[SiliconKid]

Thanks guys, those last 2 posts cleared everything up and confirmed what I was thinking and answered my question directly.

Thanks to everyone for giving intelligent and sensible feedback to my original post in this thread.

Suggestions for potential improvements to the MakeMKV GUI based on all this discussion are:

1. Don't nest the Core track under the MA track visually. Put them on the same level.

or

2. If they remain nested, then if the user checks the top level MA checkbox, the nested checkbox should automatically tick too and
should gray out and disable so it cannot be toggled independently.


In the meantime I also did my own further investigation and ripped the same BluRay with DTS-MA audio several times with
MakeMKV using different combinations of those checkboxes to see what would happen.

The results are summarised as follows:

1. Rip with ONLY the top level DTS-MA checkbox checked: Produces an MKV with ONE audio track which is the full DTS-MA
track that includes the DTS 5.1 Core and is fully backward compatible with older players that don't support DTS-MA.

2. Rip with BOTH the top level MA checkbox and the nested Core checkbox checked: Produces an MKV with TWO audio streams,
the first being the full DTS-MA track as per point 1 above, the 2nd being the DTS 5.1 Core track on it's own.

This situation is redundant and is the scenario that caused me confusion. There is NEVER a reason to do this because
effectively you now have the DTS 5.1 Core track on in the MKV twice, once as part of the MA track and once as a standalone
track. But because of the excellent backward compatability of DTS-MA, this is completely unnecessary because older media
players that don't support DTS-MA will simply extract the Core track from the MA track and play that, they do NOT need
the supplementary track.

3. Rip with ONLY the nested Core track checkbox checked: Produces and MKV with ONE audio track which is the DTS 5.1 Core track.

This scenario is valid for people who simply don't care about DTS-MA and would like to save disk space and only want the Core 5.1
track.

Given the following difference in track sizes between DTS-MA and Core only (for the disc I was experimenting with):

Full DTS-MA track: 4.78 GB

Core 5.1 track: 1.33 GB

I think it's fair to say that this is a legitimate scenario and probably worth consideration for many people because MA takes up a
LOT of space.