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Tuesday, December 27, 2005

What a Pain

One of the things I got for Christmas was the Memoirs of a Geisha soundtrack. As with all my other CDs, I immediately wanted to rip it for my MP3/Ogg collection. This sounded simple, but ended up being rather unpleasant.

The first sign of trouble came when AudioCatalyst couldn't calculate checksums for the tracks. Looking at the manual, the reason this would occur is that there wasn't at least one frame of silence at the beginning and end of each track. One thing this may mean (which is what I initially suspected) is that the tracks are not discrete, but transition directly from the end of one track to the beginning of another, with no inter-track delay (the Gladiator soundtrack did this, just to name one prominent example). This is troublesome because it's difficult to perfectly mimic this in lossy audio formats, as well as that it sounds bad when you play the tracks on shuffle (like I do).

Well, the real reason turned out to be even more annoying. A quick look at the tracks revealed that there was noise at the beginning and end of each track; but even just looking at the waveform, it was oddly shaped noise. The frequency graph confirmed what I'd suspected from looking at the waveform: there was a prominent spike at an upper frequency, embedded in otherwise brown noise; further investigation revealed that this spike was centered at 15,733 hz. At the beginning and end of tracks (it fades out in towards the center), this peak stood about 50 db above that of the surrounding noise.

While this spike was only present at the beginning and end of the tracks, I soon found that a different spike was present throughout most of the track. Some careful isolation revealed that this spike was centered at 15,700 hz. The intensity of this spike varied anywhere from 14 to 27 db, and may be different intensity on the two channels.

The 15,700 hz spike I managed to dispose of, by means of manually performing notch filters on each track. The 15,733 hz spike, however, I left, as it would be a pain to deal with, only at the beginning and end, and it's not present during most of the tracks.

So, now that we know what these spikes (hums) are, why are they there? Unfortunately, I don't know the answer, though I can think of a number of possibilities. It could be the hum of some piece of equipment in the studio, during the recording of the music (though I've never encountered this kind of thing before); I'm told that power supplies could produce hums in this frequency range. It could also be some sort of resonance with a stray instrument or item in the studio, causing it to vibrate and amplify those particular frequencies. Finally, it could be some kind of watermark or rip-protection system; if it was the latter, I could test for it by recording the music directly from my stereo (a significant amount of work, considering that the stereo's in a different room than my computer), but I don't really have any way to test the first.

So, there's Q's unsolved mystery of the week.

Sunday, December 25, 2005

Q's Do-It-Yourself Anime Christmas

Yeah, so that title kind of sucks. What it's supposed to mean is: what anime/manga (note the glossary at the end of the post) Q recommends you get yourself for Christmas (and would consider them all worth the money).

Ai Yori Aoshi (manga & anime). A "guys'" love story about two rich (before the guy ran away from his home, that is) kids betrothed to be married, and trying to get along living together (and, of course, plenty more female characters that love the guy as well). Lots of humor, an amusing story, and typical Japanese ecchi* (though not hentai). I originally started watching this series because it sounded similar to one of the stories I wrote; this similarity ended up being pretty shallow, but I still liked the series a lot.
Azumanga Daioh (manga). Awesome comedy series about the daily life of a group of... unique Japanese high school girls, and their equally unique teachers. There's also an anime version, but I don't consider it near as good, as the conversion from the comic strip format of Azumanga Daioh to anime is quite poor.
Elfen Lied (anime). An extremely vicious diclonius (a two-horned human subspecies, with a number of invisible arms - vectors) escapes from a research facility that has been experimenting on her (and other diclonius) for years. A second, infantile personality develops, allowing her to live peacefully with a boy and his cousin, until the research facility attempts to reclaim her, and her original personality reappears. Primarily drama and action (with very graphic violence), but also a good amount of comedy, and ecchi. There's also a manga, which covers almost twice as much material as the anime, but it has yet to be released in English (and fan translator groups have only gotten about 1/4 through translating).
Full Metal Panic (manga and anime). An elite mercenary (raised in war zones worldwide) has difficulty adjusting, when he is sent to live the life of a Japanese high school student while protecting a female student from a terrorist organization. Best for it's comedy, but also a moderate amount of drama. Can occasionally be ecchi.
Great Teacher Onizuka (manga and anime). None-too-bright biker gang leader turned teacher takes on the school's most delinquent class, and proves that he can do a better job teaching with his brawn and heart than the other teachers can do with their ivy-league diplomas. Comedy and drama, with a bit of ecchi. The manga is almost twice as long as the anime.
Love Hina (manga). The lord of ecchi (more than my taste, actually, but it has more than enough good stuff to make up for it). The story of a boy (attempting to enter Tokyo University, the most prestigious college in Japan) who inherits an inn turned girls' dormitory from his grandmother. In this process he develops various relationships (of various natures, and only one of them ending up being romantic) with the girls in the dorm. Hilarious comedy, as well as drama, and a bit (okay, maybe more than a bit) too much ecchi. There's also an anime, which contains some material not in the manga (although the reverse is true, as well), but I don't like it as much as the manga (although I do prefer the ecchi-light of the anime, which is the one I saw first).
Noir (anime). A pair of assassins make their services available for hire under the name of 'Noir', but soon discover that the name was already used by an ancient secret society. An interesting and amusing series (primarily drama), though things sort of start to suck near the end.
Rurouni Kenshin (manga and anime). Fictional story set in historical Japan (around the 1860s) and anchored around real events and people. Kenshin, a legendary assassin/warrior from the Meiji Revolution (a fictional character, although inspired by the real Hitokiri Gensai from that time) vowed that after the revolution he would no longer kill, but find another way to continue to help the people of the world. So, he wanders from place to place, doing what he can, using his legendary swordsmanship and sakabato (a reverse-bladed katana, where the normal cutting blade is merely a blunted edge, and thus cannot be used to kill). Primarily drama, with a good dose of comedy. I'd consider the manga better than the anime, although both contain material not in the other.
School Rumble (manga and anime). Kenji (male) enters high school with a proud reputation as a delinquent, and has his eyes set firmly on Tenma (female). Tenma, however, is too thoroughly smitten by Oji (male) to notice; Oji also seems to be pretty clueless in general, let alone about her interest in him. Primarily comedy, some drama.
Stars (Seikai) Trilogy (Crest of the Stars, Banner of the Stars, Banner of the Stars II; manga and anime). A sci-fi series about a noble human boy entering the Abh (you just know the original design concept was 'blue-haired elves in space') military, where he becomes a friend of an Abh princess also in training, who commands her own small ship. Ultimately, a war breaks out between human and Abh, which they must participate in. War, culture clash, growing up, falling in love, etc.; primarily drama, but some comedy (and it's rare for the Japanese to not throw in at least a tiny bit of ecchi for good measure).
Yotsuba &! (manga). Another hilarious comedy series by the author of Azumanga Daioh, about an exuberant (and rather psycho) little girl, enjoying life to the fullest.

Anime: Japanese "cartoons". Unlike American cartoons, anime may be for any age group, and may, in the extreme case, be pornographic.
Ecchi: Kind of like 'risque' or 'lewd'. Anything from panty shots to actual nudity (in Japan this is acceptable material for network television).
Hentai: Animated pornography (note that nudity alone is not sufficient to call something hentai).
Manga: Japanese "comics". Again, may be made for any age group, and may even be pornographic.

Thursday, December 22, 2005

& Debates - Fidelity

This one (registration required) is actually not one of my debates, although it's a timely topic that was brought up in another thread (and thus I'd been thinking about it, as well):
So this is the place to discuss serious matters. I love it.

Anyway, I also have something that I'd like us to talk about. Throughout the generations, we're taught that once one reaches a certain age, one marries, has children and continues to live on, without thinking much about it anymore.

At the center of all of this lies fidelity. When you're in love, you can't imagine ever wanting someone or something else. But I've been thinking about this for most of my adolescent life, and even though I am romantic and I really want to believe in eternal love and faithfulness, I think fidelity is against human nature. And that love and desire sometimes go hand in hand, but that they're not one and the same.

Please do not think that I'm pleading for adultery here, I just want to know what you think.

Sunday, December 18, 2005

Q1 Register Set

As mentioned previously, the Q1 has 32 32-bit general purpose registers, as well as the instruction pointer, instruction register, and various flags. I've adopted the MIPS register naming convention (registers 0-31 being $0 to $31), because it elegantly allows the use of register nicknames: aliases for certain registers, based on the designated function of the register (we'll come back to this in a couple paragraphs).

Of these 32, 31 are truly general purpose - the software can do anything it wants with them, and the CPU doesn't care. Register 0, however, has a very special purpose: it is the zero register (a concept I read about in the MIPS architecture, and found particularly useful). The zero register always contains the value 0, regardless of what is written to it; this allows the value 0 to always be available to the program, as well as allowing unneeded values (such as the result of subtraction, when all you really care about is the value of the flags - for a conditional branch) to be discarded without overwriting another register.

$31 is nicknamed $ra - the return address. This register is supposed to hold the return address for the current function (at least when the function returns). If the function calls other functions, it must be sure to save and restore its own $ra. As with all the registers that follow, this is not a hardware restriction (as it was in the case of $ra on MIPS), but a software convention that should be followed so that all code remains compatible.

$30 is $sp: the stack pointer. As previously described, the stack is a software structure on Q1; however, as it's integral to the operation of functions, it must be standardized. As with MIPS, $sp always points to the NEXT available stack location (rather than the first occupied stack location, as with x86).

$29 is $gp: the global pointer. This is more of a reserve for function use. Well-behaved Q1 programs should not hard-code the addresses of their global variables. Rather, they are expected to, should they need to access global variables, construct a pointer to their global variables by adding a (negative) offset to the instruction pointer (which can be obtained with the LRA - load relative address - instruction). The global variables can then be accessed through $gp + offset. This variable is nonvolatile; if a function uses it, it must save and restore the previous value, so that it does not overwrite the previous function's $gp.

$2-$5 are $p0-$p3: the first four 32-bit (or smaller) parameters passed to a called function. On return, $2 is $rv: the return value (if the function has a return value of or less than 32 bits).

$2-$15 are also $v0-$v14: the volatile registers. Functions may use these registers however they like, without regard to saving previous values. Thus, if a function needs a value preserved while calling another function, it must either use a different register, or save the value on the stack. These registers allow for functions to do short-term calculations (where the intermediate values are inconsequential, and may be overwritten, and only the end result is important) without the need to save registers on the stack.

$16-$25 are $n0-$n9: the nonvolatile registers. Functions may use these functions however they like, but must save and restore the previous values of any registers they use. These registers are thus saved across function calls, and may be used to store values needed after the call, without the need to save the registers to the stack.

Having both volatile and nonvolatile registers allows for best-of-both-worlds optimization. Intermediate values that will not be needed more than a few instructions later (and not across a function call) can be placed in the volatile registers, and no prolog or epilog code is needed to clean them up. On the other hand, important values can be placed in nonvolatile registers, where cleanup overhead is only needed if the called function actually uses the registers (a probability that is decreased by the fact that the volatile registers are available for quick computations).

The remaining 4 registers are reserved, at this time. The register set isn't 100% final, and I may yet find a use for them.

Saturday, December 10, 2005

Asynchronous I/O - Emulation Plan

One of the really cool things I have planned for LibQ is an emulated asynchronous I/O server. This server emulates asynchronous I/O either on systems that don't support it natively (like Windows 9x) or on data sources that operate synchronously. This latter item, in particular, is useful, because it allows you to add on asynchronous I/O support on almost anything (for archive file libraries, for one example).

The basic design of CAsyncServer (a singleton) is pretty straightforward. It maintains two thread pools (and separate request lists), which function almost identically: dequeue a request from the request list, perform the operation synchronously, perform the completion notification, then grab another request, sleeping if none are available. It's very straightforward.

The first thread pool is exactly what you'd expect: a pool for issuing calls for file system files (things you access directly through the operating system). As all of these are exclusively I/O (save for the bit of processing overhead required for each call), the size of this pool is capped only at a large number of threads (something to prevent the system from getting swamped by huge numbers of threads), and all of them execute in parallel. If the list of outstanding requests becomes too long, the dispatcher will spawn another worker thread for the pool.

The reason that there are two pools is due to the fact that CAsyncServer is intended to also work as a server for things other than file system files. One thing I plan on using it for is QuarkLib, the library for Quark, my archive file format. In this case, most operations will require a moderate amount of CPU, as most data will be compressed. If you tried issuing a bunch of operations like this on the first thread pool, with a sky-high limit on the number of concurrent threads, the entire system would grind to a halt. The second thread pool, then, is limited to a small number of threads (around the number of CPUs in the system, give or take). While there may be some waste due to file system access, this will ensure that asynchronous I/O server won't strangle the entire system.

Friday, December 09, 2005

& More Infatuation

Just finished watching Elfen Lied, again, and I still like it a lot. Grabbed a beautiful new desktop from it, too. Again, if you can get your hands on it (and can stomach the gore), go watch Elfen Lied.

Wednesday, December 07, 2005

& Debates - Truth and Fiction

The latest installment (registration required) in Q's never-ending supply of debating material, and this one's a whopper:
So, I've got this thing called a-p mail that I invented for one of the stories I'm writing. That's anonymous private mail: an e-mail system that allows a piece of encrypted mail to be routed on a public network from a sender to the intended recipient (which the sender must know) without the mail server ever knowing the identity of either. This is not to be confused with something like an Onion network, which can act as an anonymous, untraceable proxy server; this is a method of getting an e-mail to the intended receiver without so much as an e-mail address to identify the receiver.

This is something I invented from scratch; while I don’t know that no one else has thought of it before, I can say that I have no knowledge of anyone else ever implementing or considering this method. This brings up the question of whether I should look into patenting it.

However, if nobody has considered this method previously, a question of ethics arises. This method was invented as a means of secure and anonymous communication between terrorists and other underworld persons, and could, if introduced to the real world, be used just the same. Assuming nobody else has publicly described the method, would it be ethical to bring it into the real world?

Not Quite Idle

Well, since the last few posts, I haven't been completely idle. I've been (from time to time) researching possible solutions to the distortions in a lot of the Mega Man 6 music. This has been complicated by the fact that I'm not that good at math (at least not anything at or above calculus). Right now I have some ideas that sound promising, but I'll have to try them before I post about them.

Monday, December 05, 2005

& Debates - Propaganda?

My latest debate topic (registration required):
As part of an information offensive in Iraq, the U.S. military is secretly paying Iraqi newspapers to publish stories written by American troops in an effort to burnish the image of the U.S. mission in Iraq.

The articles, written by U.S. military "information operations" troops, are translated into Arabic and placed in Baghdad newspapers with the help of a defense contractor, according to U.S. military officials and documents obtained by the Los Angeles Times.

Many of the articles are presented in the Iraqi press as unbiased news accounts written and reported by independent journalists. The stories trumpet the work of U.S. and Iraqi troops, denounce insurgents and tout U.S.-led efforts to rebuild the country.

Though the articles are basically factual, they present only one side of events and omit information that might reflect poorly on the U.S. or Iraqi governments, officials said. Records and interviews indicate that the U.S. has paid Iraqi newspapers to run dozens of such articles, with headlines such as "Iraqis Insist on Living Despite Terrorism," since the effort began this year.
Los Angeles Times (found via Mac's blog)

So, couple questions for debate. First, is this propaganda, when it's factual? And in either case, is this acceptable practice (not poor ethics)? If yes, how do you handle the fact that the stories lie about their authors? If no, what do you have to say about the fact that the citizens would be less likely to trust (factual, in this case) news from the US-promoted government?

AMD Opteron Architecture

Dark_Brood found me an amazingly detailed site with more than you ever wanted to know about the Opteron architecture.

Spoils - UPDATED

Just a couple of the tracks I've extracted (and had time to edit and encode):

UPDATE: Reuploaded the new files, after recompressing them in standard quality mode, so they should be significantly better quality.

Friday, December 02, 2005

Vorbis Bad!

Well, this isn't a happy discovery. While editing the music from Mega Man 5 (to archive it in my library of game music), I discovered that Vorbis was destroying the upper frequencies of the tracks at 70 kbps (I set it to encode at 80 kbps, as they're all mono, but for some reason on MM5 it decided to use 70). Take a look at the results:

The original track, after ADPCM decompression:

The same track, after Vorbis compression at 70 kbps:

The track at 80 kbps (forced by reducing the range of allowable bitrates):

The track again, at 96 kbps:

UPDATE: Hmm. Looks like this is actually only a problem when not using standard quality mode (was using average bit rate mode before). In other news, lots of Mega Man 6 music is recorded at high volume, and noticeably distorted. Maybe I should send an e-mail to Capcom...

Thursday, December 01, 2005

Little Change to Asynchronous I/O

I've decided to make a slight change to how LibQ handles one of the three methods of completion notification. Instead of using a CEvent to notify the application of I/O completion, the new method internalizes the waiting process. Practically, instead of waiting on a CEvent you specify when the you begin the I/O, you'll now wait on the CAsyncStatus for the I/O, itself (this requires that the operation be marked as waitable, when initiated).

There are a couple reasons for this. First, it should be a little faster on POSIX systems, due to more direct OS support. Second, it will allow timed waits on I/O completion (remember that timed waits could not be implemented with the CEvent on POSIX, due to technical difficulties).

A third benefit, although I don't know if I'm going to even do this, yet, would be that it allows the possibility of waiting for multiple waitable I/O operations at once, returning when one of them completes (or the timeout expires). However, due to incomplete OS support, this might be slower than desired.

& Debates - Pornography

My lastest attempt (registration required) to incite flame wars for my own amusement:
From Social Psychology, eighth edition (my social psychology text book), by David G. Myers, pages 399-400:
Evidence also suggests that pornography contributes to men's actual aggression toward women. Correlational studies raise that possibility. John Court (1986) noted that across the world, as pornography became more widely available during the 1960s and 1970s, the rate of reported rapes sharply increased - except in countries and areas where pornography was controlled. (The examples that counter this trend, such as Japan, where violent pornography is available but the rape rate is low, remind us that other factors are also important.) In Hawaii, the number of reported rapes rose ninefold between 1960 and 1974, dropped when restraints on pornography were temporarily imposed, and rose again when the restraints were lifted.

In another correlational study, Larry Baron and Murray Straus (1984) discovered that the sale of sexually explicit magazines (such as Hustler and Playboy) in the 50 states correlated with the state rape rates, even when controlling for other factors, such as the percentage of young males in each state. Alaska ranked first in sex magazine sales and first in rape. Nevada was second on both measures.

When interviewed, Canadian and American sexual offenders commonly acknowledged pornography use. For example, William Marshall (1989) reported that Ontario rapists and child molesters used pornography much more than men who were not sexual offenders. An FBI study also reported considerable exposure to pornography among serial kills, as did the Los Angeles Police Department among most child sex abusers (Bennett, 1991; Ressler & others, 1988).

Although limited to the sorts of short-term behaviors that can be studied in the laboratory, controlled experiments reveal what correlational studies cannot - cause and effect. A consensus statement by 21 leading social scientists summed up the results: "Exposure to violent pornography increases punitive behavior toward women" (Koop, 1987). One of these social scientists, Edward Donnerstein (1980), had shown 120 University of Wisconson men a neutral, an erotic, or an aggressive erotic (rape) film. Then, the men, supposedly as part of another experiment, "taught" a male or female confederate some nonsense syllables by choosing how much shock to administer for incorrect answers. The men who had watched the rape film administered markedly stronger shocks, especially when angered with a female victim.

In a sidebar on page 400:
Repeated exposure to erotic films featuring quick, uncommitted sex also tends to
  • decrease attraction for one's partner,
  • increase acceptance of extramarital sex and of women's sexual submission to men, and
  • increase men's perceiving women in sexual terms.
(Source: See Myers, 200)