This...is very, very difficult to explain. Basically, the best way I can do so is to talk about an example from ComicFury that happened quite a while ago. (Somewhere between 2012 and 2014. No idea where.) It was talking about how JPEGs, when properly done, can look just as good as PNGs. The person advocating this gave a picture, originally some other file type (BMP I think), and posted what it looked like as both a JPEG and PNG. Most people agreed that it looked the same.
...But it wasn't. I could tell there was something different about the two images by looking at them side-by-side. I couldn't tell what it was, but I could tell there was a difference between them, and I struggled to figure out how to explain this to them. After a little back and forth, the person managed to figure out that, yes, I did have a sharp eye for it--there were in fact differences. I believe it mainly had to do with the JPEG doing some aliasing (or is it anti-aliasing? Whichever is the one that blurs the differences between colors), albeit very subtly, as part of the compression, whereas the PNG left it as-was.
This made sense, since to me, when I looked at the images, I never was saying that one was better than the other. I was just saying they looked different from one another, especially in the colors, and that's because I was right. I ultimately was concluding that the difference between the two could easily be an artistic choice in style (because some artists prefer sharp, crisp differences, and others don't), but I knew that it was a difference, something that most people didn't notice that I did.
That type of thing happens all the time. I spot little things that others don't. My eyes just work differently. In what I see, in what I focus on, too. I will jump to areas that others don't. I find things that way a plenty. And then there's also how my eyes perceive the world. Think about things like objects. I see the lines in them. I see the shapes in them. I see them as if they were a 3-D object being created in a program, sometimes complete with a spine, an outline, and whatnot. I see things flow. I see things blocked out. I see both the architecture and natural methods, compiled simultaneously in my head to project what the object is.
At the same time, I can also see how that object would be applied. A pencil may be just a pencil in my hand. It may be a pencil in the hand of a character. It may become a Jokeresque weaponized pencil. It might actually be a dagger or even lightsaberesque energy blade of some sort. It could be a spear. It could be a gun. It could even be a spaceship. I calculate all of these whenever I hold the objects I fiddle with: I'm projecting not only what their shape is, but what that shape is good for.
My ears work the same way. They've got a distinct downside. I can't make out what others say very well. I often have to ask them to repeat what they say multiple times for me to hear them, and even then, I probably didn't perfectly get the message, with me mostly relying on body language to more or less guess at what they just said rather than actually having heard them. I fake it, but words from others simply don't get processed in my brain very well.
It goes both ways, too. I can't actually vocalize myself and know I'm getting the message across clearly. I mumble. This has a bit to do with my autism, but it's also my ears. I can't really hear my voice that well so I don't know if it's barely a whisper or a loud shout. Volume is all wrong all the time. It simply doesn't work, my ears' ability to pick up on language and know sound-wise what to do. (This, incidentally, contributes to why I'm considered tone-deaf. Yes, I hear crystal clearly, with absolute clarity and precision, EXACTLY how my voice is off. I'm well aware of the problem. It's just I utterly and entirely lack the capacity to FIX it.)
That's the downside. The upside? My ears are hyper-sensitive in ways that surprise others. I can hear things long-distance that most people think I shouldn't be able to hear. (Admittedly it works the other way, though; I can't hear things long-distance that people think I should. Again, fundamental difference in how my mind works compared to theirs.) I can pick up on multiple conversations from multiple places (though this has the disadvantage that I need to listen to one with focus else I end up listening to none), even with distractions, in a way that I imagine is pretty rare.
Not too unusual, but I'm getting warmed up. My ability to hear background sounds is incredibly good. All those sounds other people filter out? I can hear them. This sounds good, but...the result is more often than not a minor form of misophonia. Especially chewing, ESPECIALLY smacking lips when chewing. (Don't even get me started there.) That sensitivity to sound can be extremely disruptive to my ability to focus, get rest, etc.
It does have the upside of letting me know when something's wrong, or picking up on neat little things others don't (like wolves in the distance, light rain on the roof, and similar), but mainly, my different hearing manifests in the form of music, as I touched upon yesterday. I can't actually harvest this ability, much to my absolute frustration. I've tried, but there's simply no way of describing it and having it be accurate.
But basically, think about any song. The average song has around 5 parts, give or take one, when you include percussion and singing. It can potentially go up to something much higher (orchestral music will have an entire orchestra, after all), but that's around the average, going up to 8 or 9 but generally never below 3. (It needs at least two unless you're a really competent singer.)
Those typically being: singer, backup singer, percussion, bass guitar, guitar, second guitar, keyboard, and other miscellaneous instrument of the band's choice: saxophones were an old rock favorite, which have made a comeback in pop music. Trombones/trumpets are a decently popular choice in genres too for their unique sound. Flutes and other woodwinds exist. A hugely popular one are string instruments, particularly the violin and/or cello.
Obviously, these don't all run at once. Usually, they're replacing something. (For instance, cello can replace base guitar or even normal guitar depending on the part. Woodwinds/violins can replace more traditional keyboards, and trombones/trumpets/saxophones can replace more electronic keyboards. The list goes on and on for what can replace what.) But a band usually can get up to that ~8 range with only 4-5 members, which a lot of bands have.
Singer and backup singer each playing an instrument, percussion, bass guitar, guitar (3), and then whatever else is needed is a really popular combo across most genres. (Keyboards and a second guitar are probably the largest for a band of five that I would listen to, though, because while alternative music is, well, alternative, a lot of alternative bands especially alternative rock bands use that sort of combo to produce epic music.)
...My point in this is that I can pick up on each and every one of those parts, at all times. Most people when listening to a song will only hear the three or so most dominant. The others lay in the background, enriching the song. But I can pick up on them, and if I focus on them, track them the entire song. (Thing is, of course, being that I never can focus; I get distracted by the 'shiny' so to speak in more dominant parts that are catchy at the moment.) Percussion plays the whole song, but it's usually not just hitting the bass drum and more than just simple snares. I can hear the change, I can hear it, at all times, even though my body has trouble tracking the different aspects of percussion at a single moment. (Know that patting head while rubbing stomach thing? Percussion is like that. I suck at it; there's a reason I was a bad percussionist. So in a song, I'll try to tap my foot to one percussion element and use my fingers for another, and it never lasts long.)
It's not just percussion. The bass guitar changes rhythm a lot, producing a lot of different notes. In fact, sometimes, the bass guitar in spite of being in the background is more busy than the actual guitar in the foreground! I know because I listen to the song, can hear it, and pick it out and know it's there, working.
And so on and so forth. This even works for similar instruments. How do I even know there are two guitars playing? Because I can hear them both, at the same time, overlaying one another, with the bass guitar also playing. One guitar will be dominant, being the main instrument, but that second guitar exists. It even works for things that aren't guitars. For electronic music, I can hear different types of electronic music playing even if they're similar, and track the different parts. Different bells? I can tell.
I see these different musical fine points. I can tell a lot about music. Fine details. Small things, changes in volume, pitch, and whatnot. I can hear it all. That's why I can pick up on a band being that particular band. Admittedly, I'm only as good as I am because I listen exclusively to The End. I wouldn't be able to identify different Adele songs. I could be better, if I listened more frequently, if I looked these things up rather than letting them pass as just guesses, if I listened to them outside of The End, basically, if I was more proactive with my musical listening.
...But the skill is still there, as something that most people probably only have the general sense of. My ability is mostly natural, because while I love music, I'm not a music buff. It's just that I can hear that thing, and know it is of this one thing, even though I can't tell you how things worked to get there, or be able to do much about it.
This is the way my mind works. That sharpness, yet having the debilitation of not knowing how to do anything about it. Incredibly frustrating sometimes, but I've learned to live with it.