DTS-HD MA Workflow?

[emanswfan]

So, any easy workflow where I can keep and process this lossless track while video editing? I've never worked with DTS before but would love to keep it. Currently I use premier pro cs5 and encore cs5 to work, but I'm pretty sure I can't work DTS through this. I just want to have a simple workflow (plus upmixing for deleted scene insertion) in which I can keep the track. I know others here have done it, but I just have no experience with this.

 

[Captain Khajiit]

Keeping your track lossless through your workflow is not really a problem because you should convert to an uncompressed format for editing, such as a .w64 file or individual mono wavs. The real issue is decoding your DTS-HD MA track. I would do this with eac3to and either Sonic or Arcsoft decoders, but both are paid software. I do not know if there is a free decoder available: NicDTS will do lossy DTS, but I do not know about lossless tracks.

If you can manage to decode your audio, you can edit losslessly all the way through your workflow, and either use LPCM on your final Blu-ray, or see what the encoder Geminigod was discussing recently can do for you.

 

[geminigod]

^

It is not possible to edit in DTS, and it is extremely expensive or difficult to encode and decode with DTS. To my knowledge, the best way to go if the disc has it is to use eac3to as-is to decode the Dolby True HD audio track to one of the two formats CK mentioned above.

At some point I need to update the thread that CK linked to, but that free program only works for encoding to DTS.

(Not sure if this is still the case, but Arcsoft used to allow you to download a trial version of their total media theatre which includes the DTS decoder that eac3to needs!)

 

[booshman]

Just want to echo what geminigod said about arcsoft. If you decode with eac3to with sonic or another decoder, you will only get the DTS core, and the other info will be discarded. Your audio will then no longer be lossless.

 

[Captain Khajiit]

If you decode with eac3to with sonic or another decoder, you will only get the DTS core, and the other info will be discarded. Your audio will then no longer be lossless.

I have never heard this about Sonic. What is the source of this information? The only limitation listed for Sonic by madshi in the first post in his doom9 thread is that it cannot output 7.1 and decodes DTS-HD MA 7.1 as 5.1. Madshi is very thorough, so I would expect there to be information about this at the start of the doom9 thread -- unless, of course, I have overlooked it, which is always possible.

While Arcsoft is no doubt preferable if you have a 7.1 track and wish to keep all the channels, outputting 5.1 is not the same thing as using only the core and discarding the rest. Are you sure that you are not thinking of Nero or libav/ffmpeg? You might be right, but I need a source for the information.

 

[nightstalkerpoet]

Most core tracks I've seen for 6.1 or 7.1 DTS-HD are DTS ES 6.1... not sure what to use for this. I will say that from my personal experience, there is a near inaudible difference between the core track and the lossless one, MUCH less of a difference than the jump from DVD quality to core. Not really worth it for edits, IMHO.

 

[geminigod]

I have never heard this about Sonic. What is the source of this information? The only limitation listed for Sonic by madshi in the first post in his doom9 thread is that it cannot output 7.1 and decodes DTS-HD MA 7.1 as 5.1. Madshi is very thorough, so I would expect there to be information about this at the start of the doom9 thread -- unless, of course, I have overlooked it, which is always possible.

While Arcsoft is no doubt preferable if you have a 7.1 track and wish to keep all the channels, outputting 5.1 is not the same thing as using only the core and discarding the rest. Are you sure that you are not thinking of Nero or libav/ffmpeg? You might be right, but I need a source for the information.

This should serve our purposes well enough rather than foraging through a very long doom9 thread. http://en.wikibooks.org/wiki/Eac3to/In_Depth_Technical_Explanation#DTS-HD_tracks

Somewhere in the eac3to thread here http://forum.doom9.org/showthread.php?t=125966 it goes into the differences between decoding with the included sonic decoder vs. the external arcsoft decoder. To my knowledge, I think what you all have said is mostly true.

Booshman is definitely right that sonic only captures the core DTS information and kills all the "extended information." This extended information is the extra two tracks as CK indicated but also appears to include additional audio information to make the DTS-HD MA track "lossless". I don't 100% understand the specifics of this somewhat confusing setup, but I think that "core" arrangement design has to do with SPDIF output compatibility and also backwards compatibility with older decoding hardware.

Bottom line, with sonic decoding, the core audio that you retrieve appears to be 5.1 @ 1509 kbps in lossy format. Now, while DTS encoded at 1509 kbps is technically "lossy", it is still a considerable objective improvement over ripping from the ac3 audio track instead. Nightstalkerpoet, you raise a good argument about whether or not there is a detectable quality difference between the DTS core audio and the DTS master. I am inclined to agree with you that at this level the difference gets highly subjective. Any detectable difference probably has more to do with psychoacoustic factors than the actual compression (except for the fact that you are losing the info in those two extra audio channels!).

I personally would rather capture that info to a lossless w64 file for editing and then downmix it myself to 5.1. Those two channels may also prove to be valuable in some way for editing. These two reasons are enough for me personally to want to use arcsoft decoder or convert from Dolby True HD instead (if there is one), which doesn't have this limitation with eac3to.

 

[nightstalkerpoet]

In the known problems section, it states this:

DTS decoding fully supports 6.1, but 7.1 tracks are decoded as 5.1 only.

Meaning that it is an eac3to problem in general, since every 7.1 or 6.1 DTS-HD track has a 6.1 core.

I can see where access to the full 7.1 tracks would be helpful in separating out individual effects.

 

[geminigod]

According to the link I posted, the core is not 6.1. It says the core is just regular DTS, which is 5.1... though maybe regular DTS actually supports up to 6.1 but 5.1 is just some kind of spec standard or something?? What the hell is 6.1 anyway? 3 sets of speakers with no center speaker?

Nightstalkerpoet, please post links to where you are getting your information. Thanks!

Also, just to clarify, it isn't an "eac3to" problem. It is a sonic decoder problem. There is no problem using eac3to with arcsoft codec. Thus this is more academic in nature now since a workflow has been outlined above to solve this issue. Nevertheless I want to make sure I understand, so please post links.

 

[STANKPAC]

What the hell is 6.1 anyway? 3 sets of speakers with no center speaker?

A center speaker in the back. 3 in the front + 3 in the back + LFE (subwoofer) = 6.1 Surround Sound. ;-)

 

[geminigod]

Funky. Never seen a center speaker in back before. Sounds a bit pointless... I guess that is why 5.1 and 7.1 are more popular arrangements.

 

[Neglify]

Funky. Never seen a center speaker in back before. Sounds a bit pointless... I guess that is why 5.1 and 7.1 are more popular arrangements.

I personally prefer Ghetto Surround Sound.

 

[Captain Khajiit]

Booshman is definitely right that sonic only captures the core DTS information and kills all the "extended information." This extended information is the extra two tracks as CK indicated but also appears to include additional audio information to make the DTS-HD MA track "lossless".

Well, I actually indicated both those things by saying that outputting 5.1 is not the same thing as decoding only the core. I have always understood that Sonic does decode all eight channels, but downmixes to six channels and outputs those, so the other two surround channels are no longer present, but the extra information is included in the output file. The wiki page does not state anything to the contrary, and I am not trawling through over five hundred pages looking for something that I am almost certain would be mentioned in the first post by madshi, especially as use of the core only is specifically mentioned for other decoders, such as Nero.

Again, I might well be wrong, but I will need to see it confirmed. For 7.1, Arcsoft is undoubtedly preferable for the reasons that you have outlined, but I can still see no reason why Sonic should not be used for DTS-HD MA 5.1 tracks (or 6.1 tracks in most cases).

I don't 100% understand the specifics of this somewhat confusing setup, but I think that "core" arrangement design has to do with SPDIF output compatibility and also backwards compatibility with older decoding hardware.

Yes; that's right.

 

[geminigod]

Lol, sometimes its just best to go to the source! http://www.dts.com/professionals/sound-technologies/codecs/dts-hd-master-audio.aspx

The audio codec overview pdf explicitly states that DTS supports "• Up to 6.1 channels at 48 kHz, 5.1 at 96 kHz" and "• Constant bit rates from 255 kbps (2 ch) up to 1509 kbps".

So we were both right! DTS does support 6.1 channels, but 5.1 is the standard I think? You said that every core is 6.1, but I have never read that anywhere. I can't find anything that 100% confirms the core is 5.1 either, but it seems highly illogical in my mind for it to be otherwise. Big reason #1: How would a rear center channel be of any use to a 7.1 setup? Many more reasons also come to mind. Thus this is what I am pretty sure gets encoded to the DTS-HD Master "core" and the rest goes to "extended" data, which is why that is what you get when you try to use eac3to with sonic decoder on DTS-HD master audio track.

SEMI-RELATED NOTE: Everyone should make sure their home audio output settings is set to "compressed" or "bitstream" instead of "PCM" if you want your audio to decode these multi-channel formats properly as the director intended it to. It is amazing how often they are not set properly because people think "compressed" sounds bad (me included before I knew better so don't feel bad if anyone reading this is one of them). Click on the spoiler for the clinically insane tech nerds who want to learn more about SPDIF and how it relates to all of this.

Reveal message

If anyone is bored, here are a couple not-so-fun reads about the history of SPDIF back in the 90's and how it influenced the current shape of all these audio formats.
http://ac3filter.net/forum/index.php?topic=10.0
http://www.epanorama.net/documents/audio/spdif.html

 

[geminigod]

I have always understood that Sonic does decode all eight channels, but downmixes to six channels and outputs those, so the other two surround channels are no longer present, but the extra information is included in the output file..

Crap. You may be right about that. Good catch. Hopefully somebody can confirm. I am too tired to research it any further.

Outstanding question #1: Does sonic downmix or throw away extra channels and/or extra sound information?

Question #2: Is DTS-HD Master core 5.1 or 6.1 channel?

 

[AEmovieguy]

Geminigod: When converting Captain America's DTS-HD MA 7.1 track to FLAC in Eac3to with the Arcsoft DTS decoder, the command line interface stated that the DTS core track was 5.1.

A little off topic: Since Sony Vegas doesn't support 7.1 audio, is it preferable to use the official 5.1 Dolby track in this instance? This is my first fanedit with a 7.1 audio source. How good of a job does Eac3to do downmixing 7.1 to 5.1 versus the official lower quality 5.1 mix on the disc?

 

[Captain Khajiit]

Question #2: Is DTS-HD Master core 5.1 or 6.1 channel?

I have seen both 5.1 and 6.1 cores. In respect of DTS-HD MA, 6.1 mixes seem to have 6.1 cores and 7.1 mixes seem to have 5.1 cores. (I am going from memory here, but I am almost certain that this is the case.) Lossy DTS-ES mixes can quite merrily be 6.1 -- e.g. the original R1 Gladiator DVD release -- so I do not see why a lossy core should not be 6.1.

Since Sony Vegas doesn't support 7.1 audio, is it preferable to use the official 5.1 Dolby track in this instance? How good of a job does Eac3to do downmixing 7.1 to 5.1 versus the official lower quality 5.1 mix on the disc?

Eac3to does a good job in my experience, so I would say downmix the 7.1 rather than use the lossy Dolby Digital track.

 

[geminigod]

I have seen both 5.1 and 6.1 cores. In respect of DTS-HD MA, 6.1 mixes seem to have 6.1 cores and 7.1 mixes seem to have 5.1 cores.

That makes sense from an efficiency and scalability standpoint. I have always understood that to be the case but started to doubt myself with all this 6.1 talk.

 

[AEmovieguy]

Eac3to does a good job in my experience, so I would say downmix the 7.1 rather than use the lossy Dolby Digital track.

Thanks for the feedback, Captain.... Somehow....... I've always known. Another week replacing the Dolby track!



On the subject of Lossless: How would you create an uncompressed LPCMtrack that's Blu-ray compliant?

(All the content on my upcoming fanedit combined is under 90 minutes, which leaves plenty of room for a LPCM option in addition to the Dolby 640. And I'd realy like a lossless option another edit coming up.)

 

[geminigod]

On the subject of Lossless: How would you create an uncompressed LPCMtrack that's Blu-ray compliant?

AEmovieguy, I don't think I have ever seen a PCM multichannel track on a BD or DVD, even though they are supported in spec. The obvious reason why is simply to conserve space by using a compressed format instead, but I believe there may be other more technical considerations pertaining to consumer hardware compatibility as well. I know it was an issue in the past, but not sure its relevance to modern times. (I allude to one reason in a spoiler box in an above post.) Perhaps CK can shed more light here.

I know I can listen to multi-channel PCM fine with 6 discrete channels on my setup with a decent receiver decoding and an optical transmission line, but can't speak beyond that. What I do know is that achieving this end result is a little tricky because the channels have to be broken up into separate streams and then either multiplexed together to send via one cable, or sent simultaneously via a bunch of cables. PCM and SPDIF interface at its most basic design level only supports 2 channels. Because of this, >2 channels are more often than not down-mixed to 2 prior to transmitting as PCM. Then the surround receiver does its best to up-mix these 2 channels back out to 5 or 7 speakers.

Heavy technical stuff aside, my recommendation is to include a stereo PCM track if you want, but don't bother with a multi-channel PCM. If you want something higher quality than ac3, I would be happy to show you my free workflow I put together for DTS encoding. :-D