Criterion's Brazil Blu Ray apparently has a matrix-encoded Dolby Pro Logic stereo track.
In other words, it's a 2.0 stream, BUT this stream has "matrix-encoded" 2 additional channels into it which can be extracted to have 4 separate channels. I tried this with foobar2000 and free_dsp_surround (which aims to do precisely that) and it seems to work. I actually get a center channel with much of the dialogue and SFX as opposed to the front channels. I only tried the plugin with the 5.1 channel layout which isn't really true to Dolby Pro Logic (which has 4 channels = front, left, center and a back center), but it still seems to do a decent job, as far as I can judge.
The Criterion website is a little ambiguous, says "with DTS-HD Master Audio surround soundtrack on the Blu-ray edition", but obviously it only has 2 channels, as seen on blu-ray.com.
So anyway, that was kinda tough to figure out. Even the blu-ray.com review doesn't mention it, so I'm guessing this knowledge has become kind of obscure. I wonder if there's any list of movies that have such a track? Downmixed back to headphones (with Dolby Headphone plugin) it definitely sounds like a step up from the original 2.0 track. Much more "roomy" and alive. (I don't have a real surround system, so this is the best I can try)
This could improve the experience of a lot of movies and more importantly give an option to create actual surround tracks for movies that don't seem to have one.
I wonder how many movies are out there with such a track without anybody (even the studios) knowing about it?
And by the way, this is just the original Dolby Pro Logic. The later version Dolby Pro Logic II (which some claim to be compatible) apparently can even mix full 5.1 channels into a stereo track. This is rather impressive, considering that it is (to my knowledge) a fully analogue technique. The original one is, anyway.
UPDATE: imdb has a "Matrix Surround" list but I am not yet sure how complete it is and whether it includes Dolby Pro Logic. Brazil for example is not on that list, nor is it mentioned in its technical specs.
UPDATE 2: Found another very interesting article on the subject in general: Matrix audio. It boldly claims that pretty much every movie since 1977 has such a soundtrack. Makes you wonder ...
UPDATE 3: Just realized I'm not the first one to bring this up. Nevermind. Still, anyone know of a list of movies that have this?
I don't have a list but there are plenty of older films that have the 2.0 on Bluray. It's fairly common as far as I know. Is there something specific you're looking for?
No nothing specific really. I know many have 2.0, but it would be nice to know whether they are using matrix technologies; and if they do, which. Sometimes it's known, other times it's kind of a "hidden knowledge" like with Brazil. For example, there's the Burbs Blu Ray with a PCM 2.0 soundtrack, but there's no telling whether it uses Dolby Pro Logic. imdb simply says "Dolby". Could mean anything right? But somebody has to have that knowledge, I'm thinking.
I mean, you can just use any decoder and see if you like the result, right? But, at least theoretically, you wanna know how it was encoded so that you can get the most "true to the intent" decoding possible.
And since it's so difficult to come by, it would be nice to have a list, I think. Similar to that Open Matte list by sporv perhaps.
I wrote this up for someone else in another thread, but can't remember where. So the short version:
Despite any 2-channel associations you might have with the word 'stereo', theatrical Dolby Stereo is a 4-channel format: left, right, centre and rear. After some earlier releases to test the water, Star Wars launched the format in a big way in 1977, with many theatres re-equipping to support it.
Dolby Stereo uses a matrix process to encode the four channels into 35mm film's two-channel optical track. Compatibility was key, and the intent was that the track would still play in a theatre with mono playback (or it was only set up with L/R stereo for some reason).
Prior to this, the only mainstream way to hear multichannel sound was on 6-track 70mm presentations. After Dolby kicked in, 6-track still had its place in high-profile venues, but its value gradually diminished until the more refined Dolby SR process arrived in 1987, after which 6-track was all but abandoned (it's worth mentioning that 6-track did maintain the advantage of stereo surround channels, though this was rarely exploited in practice).
5.1 Dolby Digital turned up in 1992 and DTS in 1993, after which Dolby Stereo tracks, though still included on 35mm prints for backwards-compatibility, began their decline.
In summary, then: if you find a DVD or Blu-ray of a film released from 1977 onwards, with the *real* theatrical stereo track (we're wary of remixes around here), it should be a 4-channel mix, which a home cinema Pro Logic decoder will reproduce (DPL II will try to simulate stereo surrounds, which isn't ideal if you're a purist). Arrow, Criterion and Shout are great at including the original tracks; Fox's Blu-rays often include the 6-track mix as a 4.1 track. Aside from those cases, there's a healthy culture of laserdisc soundtrack restoration in these parts - check out the audio forum.
Essentially every film from 1977 to the first modern digital sound age should have a four channel matrixed Dolby variant. Until Dolby Digital, DTS and SDDS fully took hold in the mid to late 90's the final matrix variant Dolby SR was still the standard mix and many films were still intended to be heard this way as it was both the standard and due to many theaters being slow to upgrade if ever.
If a film has a 2.0 track on any release and it isn't audibly mono then there is a good chance that a receiver will decode it properly into ProLogic unless there has either been trickery and it is a remix or if it was merely a stereo only release or a stereo track-or if it is a folddown of a mutichannel remix.
The first official Dolby Stereo release was the 1976 A Star Is Born. The system was implemented into standard Dolby theater decoder mechanics, so that you had Dolby A type Stereo surround decoders which lasted into the late 80's with several updates before being replaced by the SR system with much improved fidelity. SR is still 35mm standard and prints to this day have it. Many times the digital sound would go out-particularly on Dolby ac3 prints as it was placed stupidly between sprocket holes- and all you could rely on was the optical Dolby. This is why I feel it is very important to preserve matrix audio mixes up through the 90's.
There were several attempts to have other competing systems, such as the 4 optical track Vistasonic which notably failed and was canned causing Raiders to be hastily redone in Dolby, or the similar non-licensed UltraStereo, and the evvntual DTS variant DTS Stereo. Also of note is that magnetic audio was still applied to release prints well into the 80's. Mono sound was still utilized well into the 80's but this is generally going to be on lower budgeted films or ones studios didn't believe in very much as the Dolby licensing was usually deemed unapproachable on smaller budgets.
The modern ProLogic varieties are actually very well done and in the cinema mode try to be accurate to the mono surround source. I've run many classic tracks in every version of PL and DTS Neo 6 and currently find that the PLIIx 7.1 system does a remarkable job at giving breath to a mono surround channel without stereoizing it inside of a 7.1 configuration. While I'd like to be as theatrically accurate as possible, home theater doesn't usually allow for that and PL went way beyond the efficiency of the theatrical decoder many many years ago.
So in short: if the film is 1977-2005 and has a 2.0 track included it is very likely to be matrix encoded if it isn't mono. Also look for the end credit Dolby logo as this is surest indicator that they were used on the film. However don't always go by that as that credit is nowhere on The Spy Who Loved Me despite it being the first matrix stereo Bond film release (there is no sound indication whatsoever) however Dolby is credited on Moonraker.
Noteable mono releases (oft lamented by the filmakers) due to budgetary reasons are The Terminator and Evil Dead 2.
I was under the impression that the sprocket space was chosen for AC3 as it was deemed less prone to wear/damage? I do recall that the 'drop' back to the optical was quite noticeable. Never got to watch anything in SDDS but I think my local cinema was using DTS just before it went fully digital.
What is interesting is that early multichannel stereo formats were mainly front based with 5 front channels for improved panning of dialogue etc., surrounds were predominantly mono until Dolby introduced split surrounds. Even then most mixes used mono surround as they were just discrete versions of the LT-RT with baby boom.
Great thread, thanks for all the info!
A few years ago I emailed the Dolby.com website asking for a list of all Dolby Stereo films. Surprisingly, the archivist took the time to scan the two official lists they have there, and emailed them back to me, giving me also permission to share them. So, here they are.
(2018-03-06, 01:13 AM)nickdiba Wrote: A few years ago I emailed the Dolby.com website asking for a list of all Dolby Stereo films. Surprisingly, the archivist took the time to scan the two official lists they have there, and emailed them back to me, giving me also permission to share them. So, here they are.
Thank you for sharing this. Long time lurker here. but being able to see the PDF finally prompted me to join.
