Whence DTS-HD Master Audio 'Limited'

[PS3SACD]

If you've installed system software v2.30 on your PS3 you may have noticed the following logo:



Why 'limited'? Well, reportedly because "depending on how DTS' speaker remapping flags were set during encode, the PS3 will downmix from 7.1 to 5.1. Apparently this isn't a bug, since DTS and Sony have given it a new label: DTS-HD MA Limited. 'Limited' as in a forced downmix, not user-defeatable."

We'll keep an eye on this and add more information about this in FAQ in due course.

[Brandon B]

Well, I just read through a pretty extensive discussion of the issue at AVS with some informed and expert comments sprinkled here and there.

It appears the issue is this:

The DTS spec contains the ability to flag for several different surround configurations:

http://www.dtsonline.com/media/DTS-HD_WhitePaper.pdf

Certain New Line discs mixed by a certain production studio are mixed for a setup with 2 pairs of side surrounds, neither of which are considered "rear" surrounds, and the flag is set to indicate this.

The PS3 is decoding this 7.1 channel DTS-MA track, and mixing the 2 sets of side surround both into the regular side surround channels, yielding a 5.1 mix. Most feel this is being "cheated" out of the 7.1 mix they were looking forward to when they purchased these discs.

In theory, applying DPLIIx post processing should recover this as 7.1 and send the stereo rear surround info to your rear speakers.

This does NOT apply to most DTS-MA 7.1 disks. Some titles is does pertain to are:

Shoot'em up, Pan's Labyrinth and Rush Hour (I think, going by memory on the last one).

So it is not "limited" as in "limited to 5.1", it is limited in that it does not allow input for configuring which 7 channel surround setup you have with proper routing based on that input. Most 7.1 disks WILL output as 7.1.

The real question is, what are everyone else's DTS-MA decoders doing, and are they all limited as well? Most products out that purport to decode DTS-MA do not, to my knowledge, ask which of the 7 configurations you have, so they are either ignoring this flag and doing something incorrect, or they are also this same "limited" decoder, and have just failed to advertise it as such.

Anyone with better or more current understanding of this, please correct me. As it is right now, this does not bother me as it seems like Sony has chosen a reasonable path to deal with the issue, and the only people who will be frustrated are those who own processors which cannot apply PLIIx to 7.1 LPCM input, and those who are perturbed that titles labeled 7.1 do not simply play that way as default. Which is understandable.

BB

[Yuri]

Unfortunately, this white paper is no longer available on DTS's site. I was hoping to find it because today I came across another flavour of DTS-HD Master Audio -- Essential.



It's on the Panasonic DMR-BW930 Blu-ray Disc recorder. See this article (Japanese).

Anyone who knows more about it please share it here.

[Jens]

The White Paper can now be downloaded here but it mentions neither the Limited nor the Essential flavour.

[Brandon B]

Well, nothing beyond some guesses that is refers to processing of DTS-ES, which seem unlikely to me. I'll dig around and see what I can find.

[Yuri]

AV Watch, where I found the above reference, today have got a link to an explanation by DTS.