I suppose I could always look on Dolby's site to find out the latest batch of EX releases, but I really shouldn't have to. Anyone from Dolby like to respond to this question: How can I identify your new sound format?????? Russ? I know you're readin'!
 

Searching for "EX" over here is a bit of a pain, since you
get "excited" and "exhibitor" too. Two other threads of some
interest (though there's plenty more):

code:

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surround EX                             02-11-2000
EX? Sorry, not with this title...       06-09-2000

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Anyhow, over in the Blade 2 topic, Chase Taylor commented that 5-digit DTS serial numbers represent EX, and Brad said something similar at some other time.

Is it actually 5-digit serial numbers, or is it all serial numbers with the high-bit set (i.e. 32767-65535)? Is this actually encoded in the serial number, or is that just a convention, and is there actually another bit or code on the DTS discs that reports it for sure?

Back on 09-15-2000 06:18 AM in (Sorry...), John Pytlak said

quote:

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One positive way of identifying the sound encoding on every print would be to write the information in the analog soundtrack area of the sound negative leaders, so it is printed onto every print made from that negative. The responsibility would fall to the sound recording facility that makes the negative, who should certainly know what type of tracks are on the negative.

---

What ever happened with that? It seems like such a good idea...

--jhawk
 

Standard SMPTE 301 "Theater Projection Leader, Trailer and Cue Marks" also specifies the locations in the leader for information about Length, Titles, Track, Lab, Company, Prod. No., Special Data, Aspect Ratio, Sound Type, and Frame Rate.

As you may know, SMPTE Standards and Recommended Practices are voluntary. Affected users are the ones who need to "enforce" them -- this means YOU! Write the distributor, asking that this complete information always be included, and why it will help have "Film Done Right" in your theatre.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
 

In your September 2000 post, you gave the impression that you were going to bring this up at SMPTE and Inter-Society meetings, in order to effect some change. It looks to me that the latest versions of the standards you cited are less recent than your post, viz. SMPTE RP152-1994 ($15) and SMPTE 301M-1999 ($24). So I'm left wondering if the conclusion of bringing it up at those meetings was, "this is already in the standards, all we can do is ask exhibitors to put pressure on distributors and labs to implement them." Or was there something else in mind?

I'm all for drafting letters, but some effort should probably go into if we'd seriously like to effect change. Probably someone who has a copy of the aforementioned standards should draft such a thing, and include clear examples of what is and is not reasaonble.

It also seems that this sort of thing is most effective when other people jump on the bandwagon. A single letter is much less persuasive than 100 letters, or perhaps a single letter signed by a large number of people.

Are folks interested in this, and would participants be willing to lend their names and affiliation to such a communication?

If so, would anyone with a copy of the aforementioned standards care to draft such a communication? If there's interest, it certainly won't break the bank for me to go buy the standards and draft something, though money is relatively tight around here.

A technical question -- what does "edge identification" refer to? Does that mean text in the soundtrack area, or does it actually refer to text outside the sprockets where edgecodes/keycodes are?

--jhawk
 

I thought that QUAD merely meant "SR+SRD+DTS+SDDS"?

--jhawk
 

The DTS-ES unit can be programmed to kick in when it sees DD pulse as well. If you need info on that, send me an email.

Also, 6.1 DTS discs are available for films mixed for 6.1. The way to tell if the disc you have is encoded that way is to look at the serial number on the disc (for the film title). If the serial number has 5 digitsl its a 6.1 mix.

Karen at DTS
khultgren@dtsonline.com
 

The only piece of advertising that seems dependable at all for identifying a Surround EX film is the movie poster one sheet itself. For instance, the "Star Wars: Episode II" poster has the DD-EX logo on it. The movie poster area of a stack ad may feature the DD-EX logo as well. The one sheets for films like "The World Is Not Enough" did not have the DD-EX logo, but the poster art in the newspaper ads did. I've only seen that with actual DD-EX films.

Unfortunately, there is a larger number of films mixed for DD-EX that are never identified as being mixed for Surround EX. Joe brought up "Fight Club" as an example. I don't remember ever seeing the DD-EX logo on any "Gladiator" or "Mission Impossible 2" art. There's a lot of other films that fall into that category as well, with "Lord of the Rings: Fellowship of the Ring" being one of the most recent examples.

To make matters even worse (well, at least for anyone keeping up with the films once they get into home release) is Dolby Labs does not allow the Dolby Digital Surround EX logo to be used on DVD packaging. They have also put a stop to allowing the logo to be emblazoned on home theater hardware as well. You may see "THX Surround EX" and "DTS-ES" logos all over the place, but the Dolby Digital Surround EX logo is strictly for commercial theater use only. That might be fine and all from a certain standpoint; however, most here would agree the identification of DD-EX theatrical releases has been very very poor overall.

One other item, there are many many Quad Format SR/SRD/DTS/SDDS print releases every year. Very few of those feature Surround EX optimized mixes. Nearly every Surround EX release has been on a Quad Format print (with "The Art of War" being possibly the only exception; it was a SR/SRD only release).

My own personal opinion is that Surround EX is largely a dud in how it has been marketed. There are very few theaters in my area equipped for Dolby Digital Surround EX or even DTS-ES for that matter. And I would bet that there is a small minority of theaters that actually uses the extended surround equipment properly (that being using it only for Surround EX mixed releases).
 

So what happens if you play a non-EX encoded film in EX? That depends entirely on the film.

Scenario #1 - You are playing a film in analog, or the film was mixed with mono surrounds. ALL of the sound in the surround channels will be directed to the rear and the sides will be dead.

Scenario #2 - You are playing a non-EX film in digital, that does have split surrounds. This is where it gets tricky. Now assuming the sound mixers did not really utilize the "stereo" part of the surrounds much, most all of your sound will be directed into the rear channel and the sides will be dead. (A good example of this is "A Knight's Tale".)

However...

Scenario #3 - You are playing a non-EX film in digital, that does have split surrounds and the "stereo" surrounds were used routinely (as is *most* of today's film mixes). You will actually have a very pleasant EX effect. Now as to whether this was intended or not is a completely different story. However I throw the movie "Vertical Limit" out as a movie that I accidentally forgot to turn off the EX decoder when I screened it and WOW! Very impressive!!! In fact, I would go so far as to say this film sounded far better than any film actually mixed for EX.

So really, it all depends.

The same method is used in the surrounds. If volume levels reach the same level of intensity in Right Surround and Left Surround channels for a particular sound element, that element will be pulled back to the Center Surround channel and the sides will go dead as Brad described.

Some films should never be played with Surround EX. That includes all analog Dolby Stereo and SR shows. You have only mono surround with those formats. Side walls will be dead and only the back wall will work. The effect is very distracting. The same thing will happen for people in DVD land when playing discs with 4.1 channel track like "The Abyss". My father did this with his new Denon 4802 receiver and thought something was wrong until I explained why the surrounds were locked to his back wall.

My opinion is no movie should ever be played in Surround EX mode unless it was mixed specifically for the format. If not, it should play in straight 5.1 instead. Now, "Vertical Limit" might be an interesting exception. But at least Brad previewed the film and made sure it sounded good (and as it turned out, very good) before selling any tickets for the show with the system set for EX. I have a strong feeling many theaters equipped for Surround EX or DTS-ES are just leaving the systems turned on for all shows whether they were mixed for Surround EX or not.
 

So really, it all depends."

SMART has taken the position since the introduction of our ex format decoders that you should at least TRY the print in ex format. In fact, we have gone so far as to say that you should leave ex on all the time (for digital soundtracks, obviously, not SR/analog with mono surrounds) and ONLY if it does NOT present a good sound EXperience, then turn it off for that particular print. I have taken heat for that position by people on this forum, but my customers seem to like it that way and are mostly VERY pleased with the results.

When you consider that the ex format is not a big deal at all, just an implementation of normal front channel matrix techniques applied to surround channels, then it is obvious that any stereo surround mix which places sounds in phase and at equal levels between the left and right surround channels is going to be directed to the rear channels. This is a normal thing to happen when sounds are, for example, panned between the surround channels. Heck, it does not even require any special encoding techniques other than a normal panpot on the console.

Now I will sit and wait patiently for the "not as intended" people to come out and jump on me. That's OK though. I am getting old and cranky. I can take it.

If it sounds good, do it!!

------------------
Oscar Neundorfer
Chief Engineer
SMART Devices, Inc.

oscar@smartdev.com
 

I suppose you're saying, "but that only works if you have DTS or SRD," and I guess that you may be out of luck for SDDS. One should compare this situation to knowing whether you're in Dolby A or Dolby SR...; it's probably a little late to develop some subtle signal hidden in the surrounds to signal EX-on and EX-off. B'sides, you might have all sorts of problems if the EX-off signal doesn't come through for some reason ("What? You only leave 8 ID frames on the last reel of the print? I leave 24!" ), or the head/tail of the trailer is chopped off, etc.

In any case, this thread, as resumed by me (after 2 years of dormancy) is an attempt to garner exhibitor interest in getting the problem fixed. So please don't say no one is trying to fix the problem... (on the gripping hand, no one seems to've chimed in response to my solicitation, hint, hint...).

--jhawk
(who doesn't actually have an EX decoder, but I suppose we could go the spare CP50 route...)
 

Did you then listen to Vertical Limit without EX to see if you could hear a difference and determine which sounded better?

Steve

------------------
"Old projectionists never die, they just changeover!"
 

Steve

------------------
"Old projectionists never die, they just changeover!"
 

quote:

---

Well, speaking of the Dolby implementation now, it appears that prints are not clearly indentified whether or not they are EX-encoded, and the hardware is not able to auto-detect EX material and switch the decoder in/out as necessary. You'd think that exhibitors who invested their $$ in the hardware would raise a stink about lack of info on which films carry EX. I mean, this thread began in 1999 and projectionists are still discussing the same problem 2 1/2 years later!

---

Clearly I spoke to the Dolby implementation, not DTS. Yes, I read Karen's comments first. I simply observed that the pure-Dolby implementation using the SA-10 seems less than ideal since it requires the exhibitor to know whether the print is EX or not (and the prints are not clearly identified, which is the real problem anyway). If I'm still not understanding something about this, correct me, but if you have a pure-SRD house, a DTS-supplied solution is not really a solution.

The DA-20 wasn't mentioned until after my comment. Fault me for not knowing about that if you want, though if you already have an SA-10 but not a DA-20, it doesn't help you much.

And you said:

quote:

---

"In any case, this thread, as resumed by me (after 2 years of dormancy) is an attempt to garner exhibitor interest in getting the problem fixed. So please don't say no one is trying to fix the problem

---

2 1/2 years have gone by and the problem still exists, therefore it seems reasonable to conclude that, up to now, nobody has tried very hard to fix the problem. Jeez, don't take it personally. It's only an observation, not a criticism. If you can get fellow film-techers to mount a campaign to get this situation resolved, more power to you.

It seems odd to me for the comment "SDDS might be left out". Dolby SA-10, DTS-ES and Smart's Circle Surround units can be configured to work with any digital surround format including SDDS. What is happening that does leave SDDS out?
 

Bobby, the comment about SDDS being "left out" was with respect to automated switching to EX. Both the DTS-6D and the DA20 can tell an external EX decoder to switch to EX. But I don't know of any such capability in any SDDS processor. So if you want do EX with SDDS, you're stuck switching it manually.

--jhawk

For starters, ALL surround EX decoders are designed to automatically switch out of EX-mode for optical formats. So (unless the EX unit has been incorrectly installed) if the EX unit is left on all the time, the bunching up of the surrounds in the rear should only happen under two very special circumstances:

1. In the rather rare case where a 5.1 digital film is mixed with mono surrounds.

2. Where an mono effect or atmos has been applied to the surrounds in an attempt to create a pseudo-stereo effect. This happens occassionally (usually in low budget films) but only works for those members of the audience sitting right in the middle of the auditorium. For most of the audience the Hass effect ensures that they hear it from one side only, so sound mixers avoid it.

There is NO such thing as EX "encoding". A film which is properly mixed for stereo surrounds should play perfectly (and usually better) with an EX unit. The sad thing in this ongoing and increasingly boring debate is that nobody asks the people who mix these soundtracks what THEY think. All we ever seem to hear is the opinion of small group of technicians who probably have never mixed a soundtrack in their life, wanting to impose their personal view on everybody else. Ask any film sound mixer what he thinks about this topic and nine times out of ten and you find they have a very different view to the technicians. Of course they want their soundtrack to sound as good as it possibly can, but having their stereo surround mix accidentally played back through an EX system is very low on their list of concerns.

The bottom line is it is more likely you will diminish the presentation of the soundtrack by leaving the EX unit off all the time rather than leaving it on all time. Of course we all agree that in a perfect world all films would be correctly marked and the exact format selected every time and everybody would be happy. But in the absense of such never-to-be-achieved pefection, the best approach is to keep an ear on what you are dishing out to the audience. You cannot force the film distributors diligent but you can be diligent yourself. Presumably you have two eyes and two ears, so my advice is play the film in EX and if it is obvious that things are not where they are supposed to be, switch back to standard 5.1

------------------
Ray Derrick
President/Chief Engineer
Panalogic Corporation Sydney, Australia
Phone: 61 (0)2 9894 6655 Fax: 61 (0)2 9894 6935

RP152-1989 discusses edge identification and mandates that the title, reel#, sound type, and aspect ratio be printed on the edge, "between the perforations and the edge of the film". Dave Macaulay, please note that it seems you were not correct---it's not the soundtrack area, but instead the area where Kodak edgecodes/keycodes appear (i.e. the SDDS area).

One suspects that RP152-1989 was never actually applied, and it might interfere with SDDS printing if it did. Anyone?

As for SMPTE 301 (of 1997), frankly it mystifies me (so it must have changed... ). Unless I misread it, it advocates printing all sorts of static stuff on the header, like the words, "Title," "Track," "Length," "Subject," "Reel No.," etc. Not ever printing what the Title of the movie actually is, just the letters "Title."

Perhaps the idea here is that an SMPTE301 negative is produced, and then the information is handwritten on the negative adjacent to the preprinted text?

John Pytlak, what have I missed?

--jhawk

Perhaps the idea here is that an SMPTE301 negative is produced, and then the information is handwritten on the negative adjacent to the preprinted text?"

Yes, SMPTE 301 specifies how the master for the leader is made. It is up to the person (editor/negative cutter/lab technician) making up the roll for printing to write the information on the negative leader, so it will be printed onto all prints.

Yes, SMPTE RP152 was written before SDDS digital sound. But the idea of writing information on the edge or track areas of the sound negative so it will print through onto each print LEADER is still valid. Since different format/language/version sound negatives may be used with the same picture negative, writing sound format information on the sound negative is the best place for the details about the soundtrack.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

I guess what I'm trying to get at is that prints do appear to be compliant with SMPTE 301, and if its intended for the negative cutter to write in this information, it really ought to say so (but again, perhaps this has changed in the -1999 rev).

I certainly agree that putting this on the sound negative is the right thing (regardless of whether it's in the analog soundtrack area, the edge area, or the picture area (if that's even technically feasable)).

I'm still left with the "how do we get that to happen?" question. It certainly appears that some labs do a great job of labeling soundtrack formats in the soundtrack area in printed text, e.g. as "-SR- SRD/DTS/SDDS" on leaders (I think that's generally Deluxe?), though they don't label EX; that's a small incremental change though.

I suppose it would be worthwhile attempting to get proper aspect ratio labelling as part of the same "battle," since its rare to see anything more-specific than "FLAT" or "SCOPE."

--jhawk

 

Sounds mixed in one of either L or R surround would come from that specific set of speakers and sounds mixed to come from both the L and R surround would instead be pumped out the B surround???
 

Maybe many non-EX films would benifit from being played through an EX decoder.

Lets take a hypothetical digital film from say a few years ago (pre-EX). The mixer often had sounds mixed in both L and R surround channels. Played back in EX these sounds eminate from the back surround. Effectively giving a better effect that the person originally imagined. Or would someone argue otherwise?

Give us the question.

Is a sound effect comming from BS better than comming from both LS and RS channels?
 

It's generally considered that surround coming from only the "back surround " speakers is worse than surround coming from both left and right, but of course it depends on context. This contextual dependancy is why it is hard to say "always leave it on," when that was not intended. Sometimes it's good, sometimes it's not, and where the boundary falls is the subject of many different opinions.

--jhawk
 

???
 

For example, let's say there's a point in the film's narrative where someone's voice comes over an intercom system and has to be heard all around. A normal 5.1 mix might sum the same audio across both LS and RS channels at the same level (a good example would be the MCP's voice in "Tron"). If you have EX activated, the audio will pull only to the back wall channel leaving the side walls dead. Intensity levels in the RS and LS channels would have to be intentionally varied to keep from isolating the audio element to the back wall speakers.

To get back to the identification problem with Surround EX, I noticed last night when visiting the Carmike 8 theater that "Blade II" was Surround EX mixed (according to the logo on the end credits). There's nothing on the film print to ID the format and nothing saying EX on the film cans either. And I don't remember seeing the Surround EX logo on any of the "Blade II" posters, just the straight digital format logos.
 

This is the difference to using the matrix for the analogue formats. For EX the steering of the matrix is not always wanted.
For this reason there is some 'encoding' involved in mixing for EX.
And in fact there is an EX encoder unit the Dolby EX-EU4 (previously called SEU4-EX).
This unit is doing something different than the 4-2-4 encoder.
The LS input is send with a -45° phase shift to the LST out, RS input is send with +45° phase shift to RST out and the BS input is added with -6 dB to both outputs.
Panning a signal between the LS and RS inputs results in a fly across the cinema.
A mono signal to LS and RS inputs is reproduced by all channels. The +/- 45° phase shift disables the steering of the matrix. The matrix just does not recognize a direction anymore.
The surround voices mentioned by Bobby are mixed in the same way.
EX can be mixed without the unit. Then the phase shift is done with a plug ins or other decorrelation techniques are used.

As for any matrix mixes it is mandatory for an EX mix to monitor through an EX decoder (switchable to check 5.1 compatibility). Otherwise the mixer has no control what he is doing.

So what happens when the EX decoder is switched on for a non EX movie.
It depends. It may sound great if there is enough decorrelation for the ambience. It may sound strange with a ambience gap between the stage systems and the back suround.
So before using the EX mode for non EX movies you should listen to the entire movie. And perhaps you should not watch for the directional effects but for the ambience sounds.
 

I guess this begs the question, "How much extra work is it for sound mixers to mix films so that they sound correct in EX, even if they're not using EX features?" Perhaps, as EX equipment becomes more prevalent, we'll move to that case where every mixing room will have an EX encoder and even if the engineer chooses not to make use of the back surround channel, we can avoid having mono surround directed exclusively to the back channel by phase adjustment.

--jhawk

It seems kind of backwards that DTS has a 6.1 Discrete format for home theater where Right Surround, Center Surround and Left Surround are all discrete, full range and with proper phase. Commercial theaters should have something equivalent to that, but none of the theatrical digital systems offer it. None of the digital projection systems do either (although I think they could add extra LPCM channels with too much hardship). I think SDDS shot themselves in the foot locking the 8-channel system into the five-up-front scheme. The extra channels might have worked better if they were reassigned to the surrounds. Tomlinson Holman's 10.2 concept is the only "next generation" idea being hawked that features a discrete 3 channel set of left, back and right surrounds (not counting the controversial ceiling surrounds).
 

With 5.1 you cannot create an all-round ambience effect with a mono signal fed to both the LS and RS channels. As I stated earlier, the Haas effect ensures only those members of the audience seated dead centre will hear this as coming from both sides. Everyone else only hears the wall nearest to them - hardly what was intended by the mixing engineer (who incidentally is usually seated very close to the centre of the mixing theatre).

For this reason nearly all 5.1 films use STEREO ambience surround tracks if an all-round effect is desired. A stereo track contains enough information which is different between left and right that even people seated well off-centre can tell the sound is coming from both sides of the room. When a stereo ambience surround track is played through an EX system it will come from all three channels (i.e even better "all-round").

Dolby's so-called EX encoder is simply a way of generating a pseudo-stereo track from a mono signal. The 90 degree phase shift applied between LS and RS for a mid-panned mono signal provides a similar de-correlation to a true stereo track and hence as Gunter says prevents the EX matrix from steering in any one direction. However Dolby's box is not required for mixing EX unless you do not have a source of stereo ambience material (like maybe if the film is being mixed in Siberia!).

The best argument for playing 5.1 films in EX is this - imagine a sound engineer trying to create an effect where the sound goes around behind the audience, such as the helicopter scene in The Matrix. With 5.1 he can only pan a mono signal from left through to right surround. However this results in the chopper going through the audience's heads not around behind them. Playing the same 5.1 track through an EX decoder produces exactly the effect the engineer was trying in vain to achieve in the first place. So the EX system often, and in fact more often than not, creates a better representation of what the engineer had in mind than playing it in 5.1

I have listened to many a 5.1 film through an EX system and only on very rare occasions has it caused the wrong thing to happen. In nearly every other instance it actually improved the directionality intended by the mixing engineer. How do I know? - I am a mixing engineer!

Also Gunter said "As for any matrix mixes it is mandatory for an EX mix to monitor through an EX decoder (switchable to check 5.1 compatibility). Otherwise the mixer has no control what he is doing".

I do not agree with this in the least! EX is very different from a fully matrixed system like Dolby Stereo. Any professional sound mixer worth his salt knows precisely what will happen when his 5.1 mix is played through an EX system. Of course it is better for him to hear his mix under all likely playback conditions, but "mandadory" - nonsense!

I think Brad has the right idea by at least giving it a try.

------------------
Ray Derrick
President/Chief Engineer
Panalogic Corporation Sydney, Australia
Phone: 61 (0)2 9894 6655 Fax: 61 (0)2 9894 6935

quote:

---

Interesting, prints of Spooky House came with a big red sticker on each reel stating "DOLBY EX".

---

I had a print (Chicken Run or Gladiator I think) last year which had the red EX stickers on the cans.
 

in my experience Dolby requires to do at least the final mix in an approved mixing facility capable of EX monitoring in order to license the movie as Dolby-EX. The more important mixing theaters are equipped with EX anyway.
So I have no idea at all why the mixing engineer could be keen to mix without EX monitoring. All the mixing engineers I work with of course use EX monitoring to do EX mixes.
Sure mixing engineers have a pretty good idea what the EX decoder will do. But sometimes the matrix is not doing what was expected. Probably you had the same experiences when mixing for the matrix that sometimes the steering of the matrix jumps between (any) channels due to some phase interaction of the various sound elements. These artefacts may happen with the matrix for 4-2-4 and the EX use. In fact there is no difference in decoding EX and the front channels of Dolby A/SR.

The surround tracks of a 5.1 mix are not allways 'true' (uncorrelated) stereo. The surround tracks usually are a mix of stereo atmos and added sound elements that are usually mono. These additional elements are not allways intended as directional sound effects and therefore often just send to both 5.1 surrounds. With the EX decoder on these sound elements will be steered to back suround. The use of the Dolby EX-encoder prevents steering if it is not wanted.
I do not agree that non directional mono elements are very rare. There is not need to move to Siberia as you mentioned, to find those 5.1 mixes. Just at the weekend I watched a French movie 'Les riveres pourpres' that did not work with EX decoding at all. E.g. they obviously used mono reverbs. This is no problem with 5.1 as it allways worked with SR mixes. When switching EX on the reverberation was steered to the back channel. Now it did not work anymore and the reverberation was annoying.

As Brad said there are 5.1 mixes that work with EX decoding and there mixes that don't work.
My point is that before using EX for 5.1 mixes you should check not only for obvious directional effects, but for subtle atmospheric effects.