[Matroska-devel] Support for DTS and DTS-HD formats in the mkv container

Phillip Maness Phillip.Maness at dts.com
Wed Jun 15 19:53:45 CEST 2011


Hi Moritz,

I checked with our certification department and they are fine with your proposal. We actually test the digital media players to properly decode the core when they receive Master Audio or High Res., so adding ADTS/EXPRESS and ADTS/LOSSLESS seems like the best approach. Would these still use the same codec ID, (0x2001) or will new ones be assigned to the new profiles?

Thanks,
Phil

-----Original Message-----
From: matroska-devel-bounces at lists.matroska.org [mailto:matroska-devel-bounces at lists.matroska.org] On Behalf Of Moritz Bunkus
Sent: Friday, June 10, 2011 12:57 AM
To: matroska-devel at lists.matroska.org
Subject: Re: [Matroska-devel] Support for DTS and DTS-HD formats in the mkv container

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Hey,

On Friday 10 June 2011 03:14:50 Phillip Maness wrote:

> I would like to add support for some additional DTS-HD audio 
> configurations to the mkv format. Currently we have A_DTS defined, 
> which seems to have been used somewhat successfully with DTS-HD 
> formats that include the DTS core substream (e.g. DTS-HD Master 
> Audio), in that DTS-HD decoders will process the complete substream, 
> and most DTS decoders will process the core substream portion and 
> discard the remainder, but I think there are some decoders that choke 
> on the DTS-HD streams.

That is indeed the case. A_DTS is used for DTS-HD as well with the assumption that DTS decoders must skip unknown content if they don't support it -- meaning the HD extensions. This was done in order not to require existing demuxers to be updated for DTS-HD as they mapped DTS and DTS-HD to the same codecs/media types at that time.

> We have two additional configurations of DTS-HD that we would like to 
> support, and these formats will definitely not play on older DTS 
> decoders, so they need be signaled differently than the other DTS 
> format. One of these formats is DTS Express, a.k.a. DTS LBR, the other 
> is DTS-HD Lossless without a core substream. (we don't have a 
> marketing name for this yet).

If they're that incompatible then they do indeed need their own codec ID in Matroska, yes.

> We have also have registered a code for the original DTS format with 
> MPEG4RA, which is 'dtsc'. I don't know if it would be problematic to 
> have a redundant definition or to switch over from the old FOURCCMap
> (0x2001) and CodecID (A_DTS)? It might make life easier for our 
> partners starting with MPEG-4 ISO media files and embedding them into 
> the Matroska container. I realize the existing codes for DTS were 
> defined prior to our registration in MPEG4RA.

I don't like renaming codec IDs for existing formats just to fit with a new naming scheme. There are tons of hardware and software devices out there that use the existing A_DTS and that would be incompatible for no good reason. Therefore I'd veto renaming A_DTS to anything else (neither A_DTSC nor anything else).

I'm undecided about splitting HD from A_DTS ( -> A_DTS). I'd argue that there are so few problems (in fact I haven't heard of a single problem on doom9 or in private mails) that I again think that breaking compatibility with existing devices is not worth it.

For the other types: the current naming scheme for codec IDs is a bit more verbose than what you're proposing. Also we don't aim to name codec ID the same as they're named in registries for other formats. Therefore what about...

> A_DTSL
> DTS Lossless

A_DTS/LOSSLESS or A_DTS/HD/LOSSLESS, depending on the marketing name

> A_DTSE
> DTS Express

A_DTS/EXPRESS

> A_DTSH
> DTS-HD

Like I said above, but if we split it up then it would be probably be A_DTS/HD.

> A_DTSC
> DTS

Like I said above, I don't want this unless you can convince me of a technical necessity for it.

Regards,
mosu

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