Here we go again with the age-old question: how do we determine whether a given audio track is either plain stereo, or "Surround"? Currently there's an update pending for the U.S. region 1 version of 'Hot Shots! Part Deux', changing two Surround-audiotracks to stereo, saying:

Quoting kaput5:

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Verified with Nero and DVD Home Theater:

- English has 3+1 tracks L,R,S, and Sub
- French and Spanish are only Stereo (2 tracks)

The problem is: I don't believe Nero (I thought that as of yet, we had not found any piece of software being able to determine this), and my HT system recognizes them as Surround. It's true that the English audio track of 'Hot Shots! Part Deux' has four channels - that in itself is pretty rare, and can easily be verified using both hardware and software players. But for the other two there is no fool-proof software solution: certain pieces of software can check whether the "Surround"-flag is set, but that's all. So I understand that Nero shows the difference between the 4-channel English track and the others, but it just isn't capable to determine whether those other two have either 2- or 3-channel audio.

Again: my HT system recognizes the other two audio tracks as 2-channel stereo with mono surround encoded (Left, Right, Surround). I know that, using the ProLogic II-feature, I can force my HT system to produce fake surround sound from even a mono track, but I've switched that off. Still it says that it has three channels, and actually produces sound from the surround speakers - which it obviously doesn't do when I put in a disc with an actual stereo track. To me, this is the only sure-fire way to establish whether something is either stereo or surround: when my HT (without engaging the ProLogic feature to force fake surround sound) recognizes three channels, then I list it as such.

If it's plain stereo I'm happy to change my ways, but then I need a way to establish it. If anyone knows of a sure-fire way of determining this, please let me know! And if there isn't, maybe we should re-think how we deal with these in DVD Profiler. Currently I see people changing plain stereo tracks to surround because they have the ProLogic-feature engaged without even realizing it, and I see people changing surround tracks to stereo using various pieces of software which aren't even able to tell the difference. People are voting yes either way, because they just don't know or just don't care. If we can't agree on what "surround" is or how to establish it, should we even track it?

I always check these tracks with PowerDVD in Media Files mode, I've never seen it disagree with my system (Denon DVD-1940, I think, to a Sony STR-DG910 receiver) in the matter of stereo vs. 2.0 surround. I don't check using the HT equipment religiously, but often if I've identified a track as surround rather than stereo using PowerDVD and I subsequently watch the disc, I'll just have a quick look and I've never noticed a different result.

Quoting Daddy DVD:

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In fact stereo movies are very rare. Most of them are made for TV. Since 1976 a lot of movies have been recorded in Dolby Stereo which when played back with a Dolby Pro Logic decoder produces sound through the LCRS speakers, before that most movies were mono.

While I see your point, I have problems with that approach as well, because of the "when played back with a Dolby Pro Logic decoder" bit. As I said, my Dolby ProLogic II decoder can produce sound through the surround speakers from a mono-track (even from a single-channel one!). That doesn't make it a "surround"-track, though. That's why I switch off the Dolby ProLogic-feature to determine whether a given audio track is actually "surround" or not: again, using ProLogic gets me surround sound from anything, so those results are meaningless.

Anyway: this perfectly illustrates the trouble with this issue in DVD Profiler. We all have our own idea of what it means and how to establish it. I'm not saying Martin is wrong - I'm just not sure enough to tell. I just know that the argument "when played back with a Dolby Pro Logic decoder it produces sound through the LCRS speakers" doesn't fly for me, since I can get the same results from a single-channel mono track. That means that I can't use that approach. So Martin and I might enter different specs for the same audio tracks, both referring to our own decoder for "proof". And someone else (see the 'Hot Shots' contribution mentioned earlier) uses yet another approach. If we're going to track this, we really should agree on what "surround" is and how to establish it.

screenshot and PM

Just change it back if you know for sure and can explain it's incorrect.

I would change it back immediately, Tim, I wouldn't even hesitate actual Stereo tracks are as noted by Martin, very rare animals in the film world, I have seen maybe THREE of them. They are more common in TV but still pretty rare. Beyond that.....

Skip

Quoting T!M:

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Now how to explain this to the thirteen (out of fifteen!) people voting for the surround to stereo-change? 

But is it not always showing:
Audio: Dolby Digital Digital Surround 2.0
even is it stereo? If you have a Stereo Dolby DVD you should test this also. Has it not lost the ability to show if it is stereo from earlier releases 3.0 or 4.0?
Rusia House 8717438131078 has stereo Audio on it
Never say Never Again has mono on it 8712626027294
When opening Media file on dvd with Powerdvd 6.0 all mono, stereo and surround are shown:
Audio: Dolby Digital Digital Surround 2.0

Quoting Giga Wizard:

Quote:
If you have a Stereo Dolby DVD you should test this also.

I have, of course, tested extensively. I even happen to own both your examples 'Never Say Never Again' and 'The Russia House', so I checked both of them as well. Especially 'Never Say Never Again' is a good example, because here the back cover indicates two of the four audio tracks to be surround-encoded. And my PowerDVD (again: in media files mode) does identify only those two tracks as "Surround", but not the others. My HT confirms this. 'The Russia House': both PowerDVD and my HT indentify all five audio tracks as plain stereo.

I've tested with about two dozen other discs, and the findings of PowerDVD in media files mode match the results as shown by my HT system every single time. By lack of a better method, I'll stick to the combination of those two checks for determining whether a given audio track is "surround" or not. If someone ever finds a better method, I'd love to hear about it.

I reiterate that it's unfortunate that we can't come to an agreement on what "surround" is or how to measure it, and that makes me wonder why we even try to track it in DVD Profiler. Even stranger is that the last program update removed the possibility to enter "DD4" - something that can easily be detected by lots of software - yet the "surround" thing that nobody agrees on stayed in...