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Comment: My experience in 1989 (Score 1) 350

I lived in Aptos, CA when the Loma Prieta earthquake happened. My home was about 10 miles from the epicenter.

My home came through it okay. Our cats were pretty freaked out but I don't think we even had any broken windows. (I've heard that the waves increase in amplitude as they get further away from the epicenter, so perhaps we were lucky to be so close.)

We were without power. I think phones were down but I'm not sure.

We didn't have much else to do, so we spent a lot of time listening to the radio. We learned some useful stuff:

* stay at home; the roads should be clear for emergency services.

* Cook and eat the contents of your freezer and fridge before things go bad.

* don't drink the water without boiling it, but it's okay to flush toilets.

* (Later) Okay, the water lines tested out, so go ahead and drink the water.

Also, we heard updates about the freeway bridge that collapsed, the destroyed buildings in San Francisco, etc.

But for the most part, the people talking on the radio didn't have anything too important to say. They filled a lot of airtime with repetitions of the above points, comments like "oh this is terrible", etc. So we stopped listening after a while and read books.

Still, in any future emergency, I will want a radio. The Internet could be down but the radio will still work. Lower-tech old-fashioned solutions are great in an emergency.

Just get a low-tech radio, rather than relying on a radio feature in something complex like a smartphone. Bonus points if you have solar cells and/or a crank to power the radio.

Comment: VP9's place in the landscape (Score 4, Informative) 109

by steveha (#49420363) Attached to: Google Rolls Out VP9 Encoding For YouTube

I'm not a codec expert. I'm just a dilettante, reading blog posts from time to time. I trust that if I screw anything up, someone will correct me.

VP9 is superior to H.264. It's based on VP8, which is not as good as H.264, but it's roughly in the ballpark (meaning it's much better than H.262 used in MPEG-2). My guess is that VP9 probably isn't quite as good as H.265, but it is definitely in the ballpark.

Google got VP8 by buying a company called On2. On2 claimed that their video coder was the best thing ever, better even than H.264, but now that people have seen the source code it's clear that was just puffery. (I guess VP8 is better than the "baseline profile" of H.264, but hardly anyone uses that; they use the more advanced features of H.264 which are better than the best VP8 can do.)

Google paid over 100 million dollars for On2. I believe they did this mostly to get insurance for their YouTube business. YouTube really needs a good video coder: if the videos are terribly high in bandwidth, Google spends too much on the bandwidth and the customers have a bad experience (videos take forever to buffer on phones and/or look bad). But if H.264 is the only game in town, Google would be totally at the mercy of the patent owners. It was worth 100 million dollars to Google to hedge their bets and have a Plan B if the MPEG licensing guys ever tried to take advantage of Google's critical need for a really good video coder.

After buying On2, Google was silent for almost a year. I believe that during that time, Google lawyers were poring over the VP6 code and making sure that nobody would win a patent infringement suit when Google released the code. Then they released the source code to VP8, and forever gave up any patent rights. VP8 is completely open source and unencumbered by patents.

The general strategy of On2 seems to have been to read all the patents from coders like H.264, and then implement something similar, but different enough not to infringe. When VP8 was released, several people here on Slashdot opined that VP8 simply had to infringe on some patents, being as similar as it is to H.264. Well, it's years later now and the lawyers haven't gotten rich by suing Google yet. I think Google is in the clear.

In fact, the MPEG Licensing Authority tried to put together a patent pool, with all the patents VP8 infringes. Over a year later, there were still no patents in the pool. Google made a one-time payment to MPEG-LA, and MPEG-LA gave Google a lifetime promise to not sue. Some here on Slashdot opined that this meant Google was admitting they had infringed on H.264 patents, but no; this was unconditional defeat for MPEG-LA, who got a little money but are not able to charge royalties or in any way control what anyone does with VP8.

Now, here's the thing: VP8 was too late to win the war with H.264. All modern phones contain hardware acceleration for H.264, but likely not for VP8. But VP9 is not too late for the war with H.265; and I'm personally cheering for the BSD-licensed technology to win over the patent-encrusted technology.

I'll still count it as a win if every phone ships with H.265 and VP9. I don't need H.265 to lose to be happy.

The one thing that worries me a little bit was the recent story that someone is putting together a new patent pool, outside of MPEG-LA. The only sane reason I can imagine for this: MPEG-LA has agreed never to sue Google; maybe someone wants to sue Google and this is the first step.

My guess is that Google lawyers didn't screw anything up, and Google would eventually win the court battle; but perhaps the FUD caused by a lawsuit would make the hardware manufacturers pass on VP9. By the time the court battle was over, H.265 would be the hardware standard the same way H.264 is now.

I hope I'm just wrong about this last part. It could simply be that a few companies want to get more money from H.265.

Comment: Re:What's "bleak" about Starship Troopers? (Score 1) 587

by steveha (#49419887) Attached to: Hugo Awards Turn (Even More) Political

In the first handful of pages you have terror weapons being used on Skinnies, something to the effect of "I'm a bomb and will explode in 30 seconds". Tactical nuclear weapons being shot off left and right. Just with the opening I don't want a future where these are valid military tactics.

I disagree. One of the points in the book was that the Terran military does have the power to obliterate whole cities from orbit (in the same way the "Bugs" obliterated Buenos Aires) but instead of doing so, they use infantry to make the destruction more selective. Right in that scene you describe, Johnny Rico says that destroying the city's waterworks is exactly the sort of thing they are supposed to be doing... it will be a massive headache for the locals with few casualties.

As for the bomb, you may call it a "terror weapon" but I put it in a different class than what we usually call terrorism. Terrorism is cutting off heads and burning people alive and crucifying people with cameras running... blowing up small children, slaughtering civilians in a deli, slaughtering shoppers in a mall, and so on. A bomb that advertises that it will blow up soon, in the locals' language, allows the locals to run far away before it blows up. Johnny Rico said the thing would give anyone a nervous breakdown (or something like that) but it's not remotely in the same class as the horrors we call terrorism.

Also, in the 50's, people believed that tactical nukes would become a battlefield staple. It was a science fiction novel; it's not surprising that it imagines tac nukes having a place on the future battlefield. In the book, most of the infantry didn't have nukes; Johnny Rico had a few, but only because he was an officer (a very junior one). Most of the bombs were simple explosive devices. And keep in mind that this was written not that long after World War II, where the normal course of things had airplanes unloading entire cargo bays full of bombs on cities. As I said earlier, Heinlein was imagining a precise application of force, and at the time that was a pretty science-fiction idea. (These days, American troops can call down a bomb or missile that can hit a single building and leave the buildings around it untouched. That's actually pretty amazing when you think about it.)

One of the core concepts of the book is the franchise is only available through Federal service.

Yes. The narrator protagonist, Johnny Rico, only wanted to serve in the military; but there were other options. His friend wanted to work in a research lab, and since the friend was brilliant, he got his wish. His other friend, a female, wanted to be a starship pilot and got that as well.

The basic idea was that by serving in the government, you showed some ability to put your needs second and the needs of the many first.

So in order to vote you must be indoctrinated into the government and there is no concept of loyal opposition.

Your biases are showing. "indoctrinated"? "no concept of loyal opposition"? I claim that these are not valid statements, and if you want to stand behind them, please cite which chapter illustrates each point.

I don't recall the exact name, but everyone was required to take a class along the lines of History and Moral practices.

"History and Moral Philosophy" They were required to take it, but not required to pass it and indeed I don't think received a grade for it.

My high school had a class called "Civics" that was not completely unlike this class, but I had to pass it. Are you horrified? Is that "bleak"?

One thing that has always stood out for me in those sections is the concept of total war.

Yes. I think it's fair to say that Heinlein believed in "total war", as so: Don't get into a war if you can help it; but once in a war, fight to win. I personally agree with this idea. Don't send our soldiers to die in penny packets; either don't send them, or send so many that they roll over everything in their path. Personally I'm a "live and let live" kind of guy, although it troubles me to think about the Islamic State throwing gay people off of buildings and all the rest of it.

Again I may have the specifics wrong, but the teachers makes a comment about "ask the leading fathers of Carthage how war never solves anything"

A student made the comment "Violence never solves anything" and the teacher used Carthage as an example of how violence had permanently solved something. Note that the teacher never said that what Rome did to Carthage was moral.

In the book, the "Bugs" attacked human colonies with the specific plan of killing every person and taking over the planets. (Johnny Rico said something about "they like the same kind of planets we like".) Therefore, in the book, there was no chance of simply negotiating a peace with the "Bugs". They started the war, they intended to prosecute the war, and the only way to stop the war would be to render the Bugs unable to continue. For that specific situation, violence was the only way to solve the problem.

Also in the book, an alien race known to humans as the "Skinnies" was initially allied with the "Bugs", but convinced (in part by that raid you didn't like at the start of the book) to ally with the humans. The humans did not exterminate the "Skinnies" and I didn't get the sense that the humans were planning to exterminate all the "Bugs".

Implying that wiping out your enemies is not only a valid tactic but is the best one.

Not in the book. You brought that yourself.

And I'll say again: the humans preferred to use the Mobile Infantry to hit exactly what needed to be hit, rather than smearing whole cities at a time from orbit. If your assertion was correct, why did the humans bother?

I think there was a single throw-away reference to a bomb of sufficient power to crack a planet open, but humans never used such a thing in the book, and there wasn't any dialog like "gee I wish we could just destroy this planet and kill every Bug."

A key message throughout the book is that the ends justify the means, that to me is bleak.

Not in the book. You brought that yourself.

If you want to stand behind that, please cite a chapter that supports it.

Comment: Re:Obligatory xkcd (Score 2) 124

by steveha (#49382507) Attached to: Thousand-Year-Old Eye Salve Kills MRSA


The point of that xkcd comic is that cancer drugs need to be safe as well as effective. A patient whose cancer cells are all dead is not better off if he is dead also.

I read the recipe for the salve and it does not appear to be something that would kill a patient. In fact, you could eat the medicine and it wouldn't hurt you; it's onions or leeks, garlic, wine, bile salts, and some small amount of copper. According to TFA the lab where they tested this smelled like garlic and people thought they were cooking food in the lab.

I'd be willing to have this stuff put on my skin.

P.S. I'm excited by the new technology being called "nanobots". (I think "nanobots" might be overselling what it is, but they didn't ask me.) A nanoscale cylinder is made that can hinge open; some drug is placed inside; and two latches hold it shut. The latches are designed to open only in the presence of a specific protein, such as a specific cancer cell type. Thus we have a nanoscale "robot" that can do exactly two things: it can open when it bumps into a specific cell type, and it can close again when it's away from the specific cell type.

This is exciting because it decouples the two problems of treating cancer: you need to kill the cancer cells and not hurt the patient. With this, you could use a very effective anti-cancer medicine that is as dangerous as a handgun bullet, but make sure that only a nanodose is delivered, and only to the cancer cells (I guess with high but not perfect accuracy).


I tried to find out more about the human trial, but couldn't find anything beyond the video linked in the above article. If these nanobots really do get tested on a human and he really has his life saved by them, I expect significant news coverage. The claim is that the guy would be dead by summer with conventional treatment, so if it's real we won't have to wait more than a few months to read more about it.

Comment: Re:Such a bad summary (Score 1) 126

by steveha (#49327705) Attached to: Boeing Patents <em>Star Wars</em> Style Force Field Technology

I stand corrected. Mod parent up. Mod me down if you like.

US patent: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8981261.PN.&OS=PN/8981261&RS=PN/8981261

With each of the embodiments discussed, the system 10 is deployed to attenuate the energy of an advancing shockwave 24 form an explosion 22 by creating a second fluid medium 30 that differs from the first fluid medium 26, which may be ambient air, positioned so that it interacts with the shockwave. As shown in FIG. 10, as the shockwave contacts the interface 90 between the first fluid medium 26 and the second fluid medium 30, the difference in refractive index reflects a fraction of the incoming energy toward the explosion 22, as indicated by arrows A. This partial reflection occurs a second time as the shockwave passes through the second fluid medium 30 and contacts the interface 92 between the second medium and the ambient 26 as it exits the second medium. All gradients or discontinuities in the medium provide a reflection point for the incoming shockwave 24. For example, if the second medium 30 is non-uniform, reflection will occur at each of many places within the medium.

As shown in FIG. 11, shockwaves 24 obey Fermat's theory of least time and therefore an effective refractive index for the shockwave can be defined that is inversely proportional to the shock speed. The properties or composition of the second medium 30 are chosen such that the effective refractive index of the second medium 30 differs from the first medium 26 in at least one of temperature, molecular weight and composition. As the shockwave passes into or out of the second medium 30, the difference in effective refractive index refracts the wave, as shown by lines B, diverting it and defocusing it away from the protected asset 18. In the disclosed embodiments, the second medium 30 is created such that the shockwave travels faster in the second medium 30 than in the first medium 26, so the refractive index of the second medium is less than that of the first medium. Further, the second medium is created to have a convex shape and therefore acts as a divergent lens, so that the energy of the shockwave 24 spreads out, as shown by lines C, so its intensity drops as it approaches the protected asset 18.

In addition, the second medium 30 may absorb some shock energy as the shock travels through it. Factors contributing to the absorption of energy include energy retained in the molecules of the second medium itself (e.g., enhanced rotational energy, excited molecular bonds, excited electrons, molecular decomposition, and ionization) and shock energy converted to electromagnetic energy through blackbody emission from hot particles or photon emission from de-exciting various excited states.

A further mechanism for attenuating the energy density of the shockwave 24 is momentum exchange. If the second medium 30 is moving relative to the first medium 26, then it will exchange momentum with the shockwave 24. The result is a combination of reflection, slowing, and redirection of the shockwave. Any or all of the foregoing mechanisms may operate in a given embodiment. The composition, temperature, speed and location of the second medium 30 may be chosen or created to create any one or all of the aforementioned mechanisms.

So, it's not necessarily lasers that generate the plasma, and the protection comes mainly from the plasma having a different refractive index than the air through which the shock wave has propagated.

My comment that this serves as a "counter-wave" is in the patent but only as a "it might also do this" thing, not as the main thing.

Countering a shock wave with a generated one would be horribly complex.

I never thought they were trying to cancel out the explosion with another explosion whose sound waves have opposite phase to the first.

I tried to read TFA and figure out what the invention really did. You are right, going to the actual patent text was a better idea. That article did not do a good job of explaining the science.

Comment: Re:Star Wars? (Score 1) 126

by steveha (#49324043) Attached to: Boeing Patents <em>Star Wars</em> Style Force Field Technology

the shields really didn't appear to do a damn thing as far as I could tell. I remember the "double front" thing now that you mention it, but I'm not sure what those shields actually accomplished.

I think the in-universe explanation is that the shields were double front to protect against fire from the laser turrets on the Death Star, but when Vader and his TIE fighters hit the fighters from behind, the front shields didn't do any good.

This has always been fine with me. These are fighters, and it would be silly for the fighters to be invulnerable. They are small, and they have decent engines, decent weapons, and (at least X-Wings) even have a hyperdrive. It would be hard to believe they could have all that and also impenetrable shields. As with jet fighters in real life, their best defense is to blow up attackers before being attacked, or avoid the attack completely. If you can hit a modern jet with a missile you likely destroy that jet, and similarly if you can get a solid laser hit on a "snub fighter" you likely destroy it.

If you accept the LucasArts video game as canon, "double front" disables all shields to the rear, using the full output of the shield generators toward the front.

the shields on Hoth did what exactly?

The in-universe explanation was that the base was secure inside its shield bubble; the ships in orbit couldn't breach the shield. So the Imperial Walkers were landed somewhere outside the perimeter of the shield, then walked up until they could attack the shield generator.

I must admit I've never bought this. If you handwave a bit, maybe you can make it make sense: they Imperials know the rebels have multiple bases, and they want to capture people alive for interrogation to find other rebels; they could have swatted the base from orbit but it would leave a smoking crater, so they wanted to take the shield down and take prisoners. This seems inconsistent with the Empire that shot down escape pods in the first movie.

Also, I have really never bought the idea that the ground base was able to protect the transports by firing some sort of weapon at the ships in space, from the ground. But never mind.

I don't recall any shields in Star Wars. ;-)

One more: spacecraft hangars didn't have airlocks; just force fields, and the spacecraft could simply fly through the force field while atmosphere didn't leak out. I've never understood how exactly that's supposed to work.

And one more: a major plot point of Return of the Jedi was that the partially-completed new Death Star was protected by a shield generator on Endor. Until that shield was disabled, the rebels couldn't even attack the Death Star.

Comment: Such a bad summary (Score 5, Informative) 126

by steveha (#49323345) Attached to: Boeing Patents <em>Star Wars</em> Style Force Field Technology

Star Wars features force fields that can, for example, hold the air in a spacecraft hangar even while a spacecraft flies out.

Boeing has developed a technology where lasers fire a burst of energy to turn air into plasma, causing a shock wave. When sensors detect an incoming pressure wave (from an explosion or whatever) this system creates a counter-wave.

Even when I squint and wave my hands a lot, those two things don't look much alike.

The prior art on this is not Star Wars, but reactive tank armor.

Comment: Online streaming (Score 1) 59

I just checked, and Rhapsody has this music available for streaming. I'm a Rhapsody customer and I'm listening to this recording right now.

I presume that Spotify and Google Play probably have this by now also. It's public domain so they have no reason not to just add it. (But I haven't checked to confirm.)

Comment: Torrent? (Score 1) 59

I would like to download the music and listen to it. But while I'm not ready to send them any money yet, neither would I like to hit their servers and cost them bandwidth.

So I'd like to torrent this. I did search and haven't found a torrent yet.

Could someone who has already downloaded it please put up a torrent?

Comment: Re:Thinkpad T440s (Score 1) 385

by steveha (#49293693) Attached to: Ask Slashdot: Choosing a Laptop To Support Physics Research?

Or you know, you could configure the ThinkPad you are buying to have a quadcore and a 3K screen.

The T440s is the "Ultrabook" form factor; it tops out at dual-core, and 1920x1080 screen size.

The T440p is the "performance" form factor, and has quad-core available, but it's thicker and heavier.

I just checked the Lenovo web site, and the T440s is discontinued. They are now on the T450s and T450p. The T450p does have a quad-core i7 option and a 3K screen option. It can also be equipped with 16 GB of RAM (vs. max 12 GB for a T440s).

I'm only recommending the ThinkPad I have. I would rather have my T440s than a MacBook Pro, but I'm not sure how well I would like a T450p (thicker and heavier; weight listed as "starting at 5.5 pounds"). Also, the top-spec T450p, if ordered directly from Lenovo, would cost more than a 15" quad-core MacBook Pro.

I think in modern science, the heavy computation is likely being done on servers rather than on laptops, so it would make more sense to go thin and light on a laptop. I'm happy with the T440s so I recommended it.

Comment: Thinkpad T440s (Score 1) 385

by steveha (#49286643) Attached to: Ask Slashdot: Choosing a Laptop To Support Physics Research?

If she's spending her own money, it's hard to beat the value of a Thinkpad T440s. It's an "Ultrabook" so it's similar form factor to a MacBook Pro. Great screen, good battery life, good processor, and Linux works out of the box.

She will need to get a mini-DisplayPort to HDMI adapter, for giving presentations where there is an HDMI connection to use. The T440s has both mini-DisplayPort and VGA connectors built-in.

I have one running Linux Mint 17.1 64-bit MATE. I got the top-of-the-line one with the 1920x1080 display, which I recommend. I got mine from B&H Photo in New York; it was significantly cheaper than other web sites I checked.


I have mine set up on a docking station, which came with its own power supply. So its power supply stays in my laptop travel bag, ready to go. Just undock and you are good to go. This is one way in which this is actually better than a Mac.

The Mac will cost $700 extra, and come with a higher-resolution display, a quad-core processor, and more RAM. That may be a better deal for her if she plans to do a whole lot of work directly on the laptop, rather than using the laptop to access remote computers.

P.S. I recommend that she take a look at the IPython Notebook, if she hasn't already. Running SciPy under IPython will be great for her.


My favorite: XKCD-style plots in SciPy


Comment: Re:i don't get it..... (Score 1) 82

by steveha (#49279969) Attached to: 3D Audio Standard Released

Now that you explained your points I don't think I disagree with you about any of the technical stuff.

I interpreted "nothing is mixed in Neural Surround" as "Neural Surround does not mix anything" which wasn't your intent. I agree that there isn't much content in Neural Surround; that press release was from 2006, and I don't know if that radio station is still doing the 5.1 broadcasts or not.

I'm a feature film sound designer and mixer, DTS is completely out of theatrical and television -- the original theater format is owned by a different company now

Correct. DTS the company split into two, and the theatre-related one changed its name to Datasat.

"optimized" for Neo:X

I think that "optimized for Neo:X" might also mean that an audio mix with height channels might have been run through a downmixer to get a suitable 7.1 mix that can be upmixed properly to 11.1. I don't know if Expendables 2 has helicopters or planes flying overhead, but if so, the people who bought height speakers might as well get some sound out of them.

"Object-oriented" audio encoding formats solve the problem in the best way: if there is a helicopter overhead, there will be an audio object tagged "overhead" and the mix can be adapted to whatever speakers the user has. If the user has height speakers, they get used. That's what I want for my living room anyway.

Comment: Re:i don't get it..... (Score 1) 82

by steveha (#49279445) Attached to: 3D Audio Standard Released

[DTS Neural Upmix is] marketed as a spatializing upmixer that can also decode Neural Surround (which is a third format not necessarily related to Neo:X).

No, there is no "Neural Surround" format as such. Neural Downmix uses phase encodings and the output is just an audio stream (can be analog, saved as a wave file, saved as DTS Master Audio, saved as MP3, etc.).

Look at this PDF. There are two columns: one shows different disk formats and how many bits per second each one needs; the other column has one thing in it, Neural Surround. This is because Neural Surround isn't a format as such.


See also this press release. A radio station was broadcasting in 5.1 using Neural Surround... broadcasting in ordinary stereo FM as well as HD radio. Anyone could listen in stereo, but those with Neural Upmix in their stereo receivers could hear 5.1 sound.


But this feature is sorta incidental, as literally nothing is mixed in Neural Surround.

I'm sorry but you are completely mistaken on this point. Let's look at the DTS web site again:

DTS Neural Surround DownMix technology reduces multichannel surround sound to a stereo mix that accurately represents the original intent of the content creator.

The DTS Neural Surround DownMix uses patented âoeActive Correctionâ technology. By analyzing the audio, the phase and intensity are rewritten, creating a pristine Lt/Rt stereo mix.

This process eliminates problems that traditionally occur in matrix surround downmix systems, such as comb filtering and spatial distortion. DTS Neural Surround DownMix creates a natural sounding stereo mix that is spatially true to the original multichannel localization.


Note the phrase "pristing Lt/Rt stereo mix" and the concerns about comb filtering in the output mix. There is mixing going on here.

DTS Neural Downmix produces a stereo output stream which may be saved in any format. You can feed the result to DTS Neural Upmix, even as an analog waveform, and it will upmix using the encoded signals. There is no disk format for "DTS Neural Surround" as such.

My understand is that the height channels are encoded sum-and-difference with the main L-R channels, and a special decoder reads reads additional channel data to subtract out the height channels from the mains.

I think it is possible that there is some additional metadata embedded in the DTS Master Audio bitstream, because old DTS decoders do understand metadata tags and will ignore them. But there is no bitstream change from plain DTS 7.1 to DTS 11.1, and you can play the 11.1 stream on an old DVD player and you will get 7.1 out. (Just like you could play Dolby Surround on a stereo and get stereo out, if you didn't have the Dolby Surround decoder to upmix from stereo to surround.)

If you are still convinced that DTS 11.1 has additional discrete channels, please find a reference and show me. If I'm wrong, I'm wrong, but I think the DTS web page I referenced in the previous post backs me up.

By "actual format" I mean its a communications channel where the sender and recipient agree on what goes into the channel and what is supposed to come out.

Then I would say that DTS 11.1 is an actual format exactly the way Dolby Surround was an actual format. Both rely on specific, agreed-upon phase encodings that are decoded to produce additional channels, and both are played back on older equipment just by playing them back. (Possibly DTS 11.1 uses metadata tags, which have no real equivalent in analog audio. But both just play back unchanged on older equipment; there are no extra channels to be dropped.)

Comment: Re:i don't get it..... (Score 1) 82

by steveha (#49278313) Attached to: 3D Audio Standard Released

There's a fundamental difference between an encoded mix and an upmixer. Dolby Surround is intended to be decoded from 2 tracks into LCRS, the filmmakers mixed the film in Dolby Stereo and were listening to the surrounds so they know what's in them. The phase encoding is part of the channel spec.

I'm with you so far.

An upmixer takes a stereo or 5.1 mix and applies effects to it to make it sound like it was mixed in a wider format, but there's nothing really being decoded, it's just synthesizing or guessing what should be in the additional channels using heuristics, all-pass filters, delays, crossover networks and other stuff that sounds cool or "provide a good experience" but, in fact, interfere with the filmmaker's intent.

The original Dolby surround and DTS Neural Upmix can both be applied to any stereo recording and some sort of upmix will occur, but both were designed to be used with a mix that was intended to be upmixed. DTS also sells DTS Neural Downmix which can take a 5.1 or 7.1 stream and output stereo with intentionally encoded signals that decode back to 5.1 or 7.1 sound.

When DTS Neural Upmix is working from a stereo signal that was made using DTS Neural Downmix, you get a really clean surround sound with no leakage. I used to listen to the multichannel recording of "Money" by Pink Floyd, and the cash register and coin sound effects very cleanly came from all the different directions like the original multichannel mix.

Again, you can't fit 8 kilos of flour into a 2-kilo sack, so 7.1 audio sent through downmix, then upmixed back to 7.1, can never perfectly reproduce the original multichannel recording. But I was impressed by just how well it did.

Despite the name "Neural Upmix", it is designed to work with phase-encoded signals intentionally mixed using Neural Downmix.

Neural Upmix is an upmixer, DTS Neo:X is an actual format that decodes an 11.1. Neo:X home receivers also employ upmixing, mainly because no films are mixed in 11.1 Neo:X, it's a surround audiophile format, and it needs to do an upmix in order to justify people spending money on it.

My understanding is that DTS 11.1 audio uses intentionally encoded signals for the height channels, but the on-disk format is DTS Master Audio 7.1 (no additional discrete channels).

Just as the original Dolby surround could be listened to in stereo if you didn't have surround speakers, the 11.1 mix can be listened to in 7.1 if you don't have height speakers; in both cases, the downmix process is supposed to not add anything objectionable.

I don't know what you mean by "DTS 11.1 is an actual format"... if you mean that it has 12 discrete channels, I believe you are mistaken on this point.

Here's how DTS describes the 11.1 system:

An important goal of the DTS multi-tiered plan is to enable content creators to produce 3D audio and provide it to consumers without changing the delivery chain. With the DTS Neo:X capability for near discrete Height/Wide output, studios can produce directional cues intended only for these speakers, with no audible leakage into other channels. Studios can also produce soundtracks optimized for DTS Neo:X that offer a compatible listening environment in âoestandardâ multi-channel playback configurations.

From the "How it works" tab on this page:


"without changing the delivery chain": no new audio format, disks play fine on older DTS decoders

"no audible leakage": there's no problem with leakage if you have discrete channels; if we are even talking about leakage, we are talking about an upmix.

I don't believe Imade any mistakes in my original post.

Hacking's just another word for nothing left to kludge.