Preserving DTS LaserDisc tracks, specifically Jurassic Park — Page 13

Surely what was on the disc WAS the theatrical DTS standard? 

Ah OK, thanks for the clarification

Theatrical sound systems are calibrated such that a -20 dBFS pink noise tone will play at 85 dBSPL from the front left, right, and center channels, while the rear channels measure at 82 dB.  This is to maintain backwards compatibility with Dolby Stereo analog tracks, which have a monaural surround capability rather than stereo rears.  In Dolby Stereo, the entire array of surround speakers is treated as one unit, which together measures at 85 dB.  So when 5.1 came along, they essentially split the existing surround in half, with the left and right each playing the same signal at 82 dB instead.  When heard together, the combined result of all the surround speakers is at 85 dB as it should be.

What this means is that because the surround channels in movie theaters and post-production stages are deliberately set to play back at a lower level than the front channels, the content of the surrounds will end up being 3 dB louder than it otherwise would be.  The mixers will set the level of the surround effects to sound 'correct' to them on the system they are listening on.  When this is played on home theater systems, which are calibrated with all channels set equally to 85 dB, the surrounds will end up being 3 dB too loud.

Because of this, a theatrical mix played on a home system must have the rear channels lowered by 3 dB in order to sound the way the mixer originally heard it.  5.1 encoders typically have a selectable option to do this automatically when creating the files for home use, but this was not always the case.

Fantastic answer, thank you.

I was just worried this was changed to adapt it to a near field enviroment

sega3dmm said:

Endian, I watched the CAV LaserDisc of Jurassic Park last night. Good old PCM Lt/Rt audio. And yes, I noticed the distortions on some lines of dialogue. I'm glad to find out I wasn't the only one.

Wooow. I definitely need to subscribe this thread here in order to be notified - someone in fact is replying in this regard and I almost missed it ...

Many thanks for having a check. At least one did it, great! After I had posted my experience here, in the meantime I also had the chance to listen to the Japanese release in Dolby Surround [PILF-1926] and it has the same weird distortions.

Perhaps those distortions were inherent to the mix. Not a miscalculation in the transfer, but dialogue distortion right in the master.

This seems to be indeed the case. At least, that slightly distorted source seems to have been used for plenty of releases. However, the interesting question is which source has been used for the 7.1 remix on the Blu-ray releases. I'm not totally sure but I wonder if it would be possible to create the audibly distortion-free parts out of the distorted ones through post-processing. Maybe I'll try that. Maybe the distorted source is the real deal as it is and they tried to make the best out of it during remixing.

Strange.

Very indeed.

Also Jurassic Park is a very hot film. It's loud and never lets go.

You think so? Compared to nowadays stuff like "Pacific Rim" which for me is just loud all the time, I would consider the soundtrack of Jurassic Park to be relatively dynamic. However I really have to watch this again myself.

Even with its imperfections, I prefer the 1994 CAV LaserDisc audio to the 2013 IMAX audio for the 3D version.

With "IMAX audio", are you referring to the 7.1 remix shared by all Blu-ray releases or is there yet another one?

Also, can you by any chance hook me up with the theatrical far field DTSHDMA of JP? I really want to listen to it right now.

By absolutely pure chance I happen to have the preserved cinema DTS stuff spread over several hard disks to lower any risk of data loss. As we know, data of which no backup exists, is not important data and this beast - distortions or not - definitely must not get lost.

However, I also are about 10000 km away from those hard disks so I could I only offer it in mid October. But I could ask the last one I shared it with to reshare it which would be only fair. Let me know via PM accordingly, maybe you already got it.

A quick update regarding the distortions:

After I finally had the chance to listen to the DTS release of the Jurassic Park LaserDisc, I can confirm that the dialogs are slightly distorted as well during the meeting scene.

Unfortunately, but hardly any surprise. After all, it’s quite likely that all home video releases had been created from the same mix at that time.

Although I can’t answer your question regarding the authenticity of this Mortal Combat release, I want to note that you should verify the mix and it’s quality on priority. Whether the track is full-rate or half-rate DTS is secondary from a technical point of view since the difference in “transparency” (ability to distinguish it from a PCM source) will be minor to non-existent for sure compared to the difference which can occur due to different mixes they might have used (or screwed up). Just so you keep that in mind while hunting for the nominally best source.

The behavior of your recorder is interesting. I’m not totally sure but I doubt that usual LD-Players even flag the 14-bit DTS as such via S/PDIF. Af far as I’m aware, every LD-Player capable of outputting PCM is able to playback DTS indirectly as well since it’s encapsulated in regular PCM anyway. So neither should the recording device care, weird.

In general, if you have a desktop PC, I can recommend a cheap PCI soundcard with the CMI8738 or CMI8768 chipset. In conjunction with the custom driver by “D0gbert”, you can capture PCM, DTS and AC3 “bitperfectly” for less than 20 dollars which is quite nice.

Judging by my own experience so far, there are at least two “mix sources”, while the newer one might have been derived from the old one by cleaning it up. Without any offical inside information, it’s difficult to say, though.

Former LDs and DVDs seem to share the same mix source with differences in mastering though:

http://www.videophile.info/Graphs/JP/JP_01.htm

The slight distortions on the dialogs, I mentioned several times here and which for reasons unknown, virtually no ones seems to care, are shared by at least the AC3 and DTS LDs and the Cinema DTS of Jurassic Park. Hence, slightly distored dialogs or not, this is most probably how Jurassic Park was simply meant to sound back in 1993.

The 5.1 LDs (whether AC3 or DTS) are nonetheless considered to sound superb despite that there is some debate whether the DTS LD has the correct mixing levels now or not.

On the first Blu-release and its 7.1 mix, the dialogs sound a lot cleaner to me but the mix and the placement of several effects (most easily to recognize during the first raptor scene) is definitely different which makes me wonder why “Disclord” in his review came to the conclusion that they essentially left the mix as it is and only seperated the back channels.

Still more than 23 years later, there seem to be still mysteries unsolved about Jurassic Park.

Regarding Jurassic Park showing up on eBay: patience! Got two copies of it myself at a surprisingly reasonable price (at least compared to highly collectables like “Fight Club”). 😉

little-endian said:

The slight distortions on the dialogs, I mentioned several times here and which for reasons unknown, virtually no ones seems to care, are shared by at least the AC3 and DTS LDs and the Cinema DTS of Jurassic Park. Hence, slightly distorted dialogs or not, this is most probably how Jurassic Park was simply meant to sound back in 1993.

Still more than 23 years later, there seem to be still mysteries unsolved about Jurassic Park.

Regarding Jurassic Park showing up on eBay: patience! Got two copies of it myself at a surprisingly reasonable price (at least compared to highly collectables like “Fight Club”). 😉

I think you underestimate the love and respect people here have for Jurassic Park. Actually having a print with cinema DTS to synch it to says a lot about how we feel. Since the slightly distorted dialog is present in more than one format I would conclude that it was there because it is probably supposed to be there.

Jetrell Fo said:

I think you underestimate the love and respect people here have for Jurassic Park.  Actually having a print with cinema DTS to synch it to says a lot about how we feel.  Since the slightly distorted dialog is present in more than one format I would conclude that it was there because it is probably supposed to be there.

While I definitely understand that, I myself am not only seeking for authenticity but also the best quality possible. And I think that Jurassic Park because of its uniqueness deserves the differences to be investigated and having cleaner dialogs on the Blu-ray is at least worth not only to be mentioned but followed up in my option.

As for passion, I keep the preserved cinema DTS audio as well as the DTS audio I diligently captured myself from the LD I aquired on eBay, on three hard disk drives with CRCs in the file names in order to never lose them or get them currupted without noticing.

How’s that for love and respect towards the original mix? 😉

Several years ago, I came across one of the original Jurassic Park DTS CD-ROM discs that was used to playback the movie theater audio back in 1993.

https://imgur.com/a/CZjGn

I’ve been trying for years to figure out how to extract the individual 6-track audio files from the disc without having to use the special DTS audio decoding equipment that was installed in movie theaters.

Today, I finally figured out how to extract the individual audio tracks from the DTS CD-ROM. I’ll outline the steps I took if anyone is interested.

It’s actually quite simple meanwhile thanks to a Foobar plugin available here:

https://sourceforge.net/projects/dvdadecoder/files/foo_input_apt-x100/

So the big challenge isn’t to decode it but to get one’s hands on those DTS CDs in the first place. 😉

little-endian said:

It’s actually quite simple meanwhile thanks to a Foobar plugin available here:

https://sourceforge.net/projects/dvdadecoder/files/foo_input_apt-x100/

So the big challenge isn’t to decode it but to get one’s hands on those DTS CDs in the first place. 😉

Yeah, that’s the software I used to decode the tracks and convert them to a usable format. I then opened the individual tracks in an audio editing app and I was able to isolate and mix the levels of each track.

https://i.imgur.com/mIXa7Ls

It’s really exciting to be able to listen to the original audio that I would have heard when I saw it in theaters back in 1993.

Doesn’t that plugin already output the correct mix including generating the LFE out of the bass part contained in the rear channels? Actually it should be possible to create a FLAC file or other format “on the fly” directly in Foobar as well.

little-endian said:

Doesn’t that plugin already output the correct mix including generating the LFE out of the bass part contained in the rear channels? Actually it should be possible to create a FLAC file or other format “on the fly” directly in Foobar as well.

Well, it kind of does. It does output all 6 channels, including the LFE channel, but for my purposes I wanted more than just a single file of all combined channels.

The CD-ROM disc contains PLAYLIST.TXT, DTS.EXE, and a folder called DTS. Inside the DTS folder are 4 files. Each file contains roughly a 20 minute section of audio from the movie. All 6 channels for that 20 minute section of the film are contained in each single file. For example, the file “S1003T6.R1” contains the first 20 minutes of 6-channel audio in the movie, starting from the DTS logo at the start of the movie till about the time the helicopter lands on the island.

https://i.imgur.com/CXTyyKT

The problem is that Foobar couldn’t open those 4 files in their native format on the CD-ROM. The files on the disc didn’t have a recognizable file extension. So, I copied the disc files to my computer and added the .AUD extension to each file. I was then able to open the files and play them back in Foobar. I still wanted to take a look at the individual waveforms themselves, so I used Foobar to convert the .AUD files to .WAV files. Each .WAV file contains all 6 discrete channels, although some of the individual tracks are paired as a L/R stereo track.

Opening each .WAV file in an audio editing app allowed me to separate those paired stereo tracks back into individual mono tracks that I could then pan left or right depending on what the track was. And I could isolate each individual track and listen to them separately, just for fun.

https://i.imgur.com/mIXa7Ls

Ah yeah okay, the channel assignment has to be adjusted. But the biggest leap is that this decoder plugin takes care of the mixing whereas the Winamp plugin puts out the raw 5.0 audio “as is”.

This plugin is so inconspicuous and unadvertised that it took me a while as well to discover it. Good find and very well worth archiving - which I would recommend doing with your DTS CD also. One never knows …

little-endian said:

Ah yeah okay, the channel assignment has to be adjusted. But the biggest leap is that this decoder plugin takes care of the mixing whereas the Winamp plugin puts out the raw 5.0 audio “as is”.

This plugin is so inconspicuous and unadvertised that it took me a while as well to discover it. Good find and very well worth archiving - which I would recommend doing with your DTS CD also. One never knows …

Indeed. I made an ISO of it back when I bought it just in case anything were to ever happen to the original disc.

Honestly, one of the coolest things I noticed when listening to the Jurassic Park theater audio tracks was being able to hear the original DTS logo that played before the movie. It brought back memories. I had forgotten about it because it wasn’t included on any of the VHS, DVD, or Blu-Ray releases.

https://www.youtube.com/watch?v=aC27RkbGuoA