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diff --git a/2020/info/35.md b/2020/info/35.md index 910a0949..276d24aa 100644 --- a/2020/info/35.md +++ b/2020/info/35.md @@ -3,9 +3,11 @@ Zachary Kanfer [[!template id=vid src="https://mirror.csclub.uwaterloo.ca/emacsconf/2020/emacsconf-2020--35-waveing-at-repetitive-repetitive-repetitive-music-zmusic--zachary-kanfer.webm" size="122M" subtitles="/2020/subtitles/emacsconf-2020--35-waveing-at-repetitive-repetitive-repetitive-music-zmusic--zachary-kanfer.vtt" duration="9:44"]] [Download compressed .webm video (12.7M)](https://mirror.csclub.uwaterloo.ca/emacsconf/2020/smaller/emacsconf-2020--35-waveing-at-repetitive-repetitive-repetitive-music-zmusic--zachary-kanfer--vp9-q56-video-original-audio.webm) +[View transcript](#transcript) [[!template id=vid src="https://mirror.csclub.uwaterloo.ca/emacsconf/2020/emacsconf-2020--35-waveing-at-repetitive-repetitive-repetitive-music-zmusic--questions--zachary-kanfer.webm" download="Download Q&A video" size="89M" subtitles="/2020/subtitles/emacsconf-2020--35-waveing-at-repetitive-repetitive-repetitive-music-zmusic--questions--zachary-kanfer.vtt" duration="6:18"]] [Download compressed Q&A .webm video (6.9M)](https://mirror.csclub.uwaterloo.ca/emacsconf/2020/smaller/emacsconf-2020--35-waveing-at-repetitive-repetitive-repetitive-music-zmusic--questions--zachary-kanfer--vp9-q56-video-original-audio.webm) +[View transcript for Q&A](#transcript-questions) During quarantine, I found myself spending time with an Android app. One of the features this app has is composing music that loops @@ -77,3 +79,231 @@ something worth looking into. # Notes Notes, references, and links at <https://zck.org/emacsconf2020> + + +<!-- transcript: 2020/subtitles/emacsconf-2020--35-waveing-at-repetitive-repetitive-repetitive-music-zmusic--zachary-kanfer.vtt --> + +<a name="transcript"></a> +# Transcript + +(00:04) Hi. I'm Zachary Kanfer, and this is waving at repetitive +repetitive repetitive music. Over quarantine, I've been bored, and I +found this Android app that has a bunch of mini-games, one of which +lets you compose music. And it works, but I want a little bit more +functionality than it offers, it's not very flexible. So, I thought +what if I made this, and what programs could I make this in that are +really flexible, are really customizable. Emacs. So, I looked into +it, and Emacs can play sounds, right? If you hit control g a couple of +times, you'll hear like an error tone, and it turns out that, that is +actually playing a WAVE file, but what's a WAVE file? + +(00:58) Well, it turns out that WAVE is a musical file format, or +really an annoying file format. So, data in it can be an unsigned +integer or a signed integer, it's not consistent, and it's +little-endian by default which is not the way I like to think about +it. Now, you can set a WAVE file to be big-endian, but if you do +that, Emacs can't play it. So, little-endian it is. There's also +duplicate data fields. Here are some fields that are fine, but then +there's a fourth field that's calculated based on multiplying two of +the other ones together, and then there's another data field that's… +you multiply those three ones together. So, it's just repetitive and +unnecessary, but you have to do it, or it's not a valid WAVE file. +Also, the last part of the file is described as data or as one website +I found said, the actual sound data. + +(02:04) Now, I don't know about you but when I see that, I think, what +is data? It turns out that sound is just a wave, and the data is just +a bunch of measurements of the height of that wave forming each +sample. So, this wave starts at 8 goes 9, 11, 13, 14, 15, and then +back down. If you just take those measurements, those numbers, put +them in a file, that's all your data is. + +(02:35) All right. Let's go to a demo of my program. So, this is what +zmusic looks like. The blue highlighted row is a single beat, there's +16 of them in this zmusic file, and each dash in the row is a single +note increasing…, starting really low all the way on the left and +going up as we go to the right. So, if we started playing, we won't +hear anything, but we'll see the highlighted beat is the currently +playing one, and we see that it loops. So, we can stop it, and now we +can click to add some notes. [Music] Even more than one note at the +same time works. [Music] And we can even add notes while it's +playing. [Music] + +(04:08) Okay, here are some other features that I didn't have time to +demo. So, you can save the music to a file, and this is interesting +because normally if there's no note in a beat, we just don't play that +beat, but if you're writing to a file you have to put something in, so +when it's playing it knows to not make a sound there. We can also use +different scales. We're using the minor pentatonic in the demo, but +you can use the major scale the minor scale or anything else. And +there's also keyboard support, but it sounds really bad, and I'll +explain why later. + +(04:48) Here are some things I learned while writing zmusic. Emacs +has buttons which are great as long as you don't put two of them right +next to each other. So, if you do that, mousing over one of them +highlights both of them. Now, that's because a button is really just +a series of characters with a text property to highlight them. So, +the fix is, you put another character between the two buttons, then +mousing over one of them only highlights the one you want, but even +this doesn't work really great for zmusic, because zmusic has a lot of +very small buttons in a row. So, it's really easy to accidentally put +your cursor over the space and click on that instead of the button. +So, I looked into unicode, and I found this character called a +zero-width space. So, we should be able to put that between buttons +and not be able to accidentally click on it. Unfortunately, a +zero-width space isn't actually zero width. If we put a hundred of +them between two other characters, you can see there's space there, +and I think what's happening is, the space is zero width but then +Emacs `put` uses one pixel between each pair of characters for the +cursor, so it's almost zero width. Some ways to play sound that don't +quite work! `play-sound` plays music, but it blocks, you can't do +things like, set other notes or even pause the music. And if you +throw it into async.el, it's silent, and I don't know why. So, the +solution I went with is taking that WAVE file, ran into the file +system, and then shelling out to a native executable to play the +sound. And that works fine as long as you only do it once, because if +you do it a couple of times at the same time like if you have a chord, +and you want to play three notes simultaneously, you get this weird +interference, and that's actually why the keyboard from before didn't +work. Also, side effects have this unexpected impact, when you saw +the demo it was running pretty smoothly, but if I just add one message +statement every beat for debugging purposes, I was getting lag and +jitter. + +(07:03) Here's the one thing I learned about music theory, music +theory is not easy to program. I was looking around to see what +concepts we can use to code the scales, to code the notes, the first +thing that I saw is scale degrees, and this when I looked into it, you +don't want to program in scale degrees. So, you see we have the +first, second, third, fourth, fifth, sixth, seventh but then it wraps +around. That octave up is also a first, and that's because both of +those notes are C, so that didn't work, and also you couldn't really +easily specify a flat or sharp. You could say a sharp third or you +know, a flat seventh or whatever, but then you kind of have these two +pieces of data that indicate the note, and I didn't love that. + +(07:55) So, I looked again, and I found intervals, and then I thought +about it, and you don't really want to program in intervals either. +It fixes some of the problems with scale degrees, you see, all the way +on the right you have an octave, so you wrap to 8, and you go 9, 10 +and that works. But you solve the same problem, you see you have a +major third but below we also have a minor third, so you saw that +problem of having two pieces of information. + +(08:20) So, I thought about it. Music is really frequencies. Like an A +is 440 hertz. So, at a low level that's what we're going to do, we're +just going to use frequencies. And then at the one level above that, +that's a little bit easier for humans to think about, we're going to +use semitones up from the root, which is kind of like scale degrees, +but instead of just counting each note as one more, we're going to say +how many semitones up it is. So, if there's a sharp between two +notes, that's going to be two steps up instead of just one. And then +we translate those two frequencies, so your A is 440 hertz, another +note might be 613.5, or whatever, and that's we use the low level to +play. + +(09:02) Some future work I have, I want to add some drums. I want to +make that keyboard actually work, and computers and synthesizers are +the only place you hear a pure sine wave like the one we have here, so +I want to add overtones or other octaves above it just to make it +sound a little bit more realistic. I've put notes references and the +source code up at <https://zck.org/emacsconf2020> [updated]. I'm one +of the organizers of EmacsNYC check that out. And if you take a look +or have any thoughts, I'd love to hear them, and thanks so much for +coming to my talk. + +<!-- /transcript --> + + +<!-- transcript: 2020/subtitles/emacsconf-2020--35-waveing-at-repetitive-repetitive-repetitive-music-zmusic--questions--zachary-kanfer.vtt --> + +<a name="transcript-questions"></a> +# Transcript: Q&A + +(00:09) Okay, yeah, so I'm Zachary Kanfer, let's go to the +questions. The first question, "Why do we go top to bottom for time +progression, and left to right for low to high?" Interesting, I +think…, so the initial thing I was copying, that initial app work this +way, and yeah, I mean, certainly traditional music, you know, on a +staff does go left to right like this. I mean, going top to bottom +does make it easier to add more beats without having to wrap, but +certainly that could be managed. Yeah, I had not really thought about +it, but it is definitely something worth looking into. + +(01:21) Two, "Will you play us another song?" Not now, I can make some +recordings of it, or certainly you can try it. I couldn't quite get +the microphone and the webcam and everything to work with the sound +playing now. So, I can record some. Also, I have put a link in the +Etherpad, <https://zck.org/emacsconf2020> [updated], where you can go +and get the source, and you can try it yourself. There's no +dependencies needed, so it's just all in Emacs. So, please, you know, +try it yourself. + +(01:57) "Any chance for an Emacs tracker or mod player?" I don't +really know what a mod player or tracker are, but I mean, I'm sure +that would be cool, maybe there's one on now, but I don't know. + +(02:11) My musical background. So, I've played various instruments +since about the third grade. Started recorder, play cello, I play +guitar now. But yeah, so just kind of random instruments, and I guess +kind of some of those things influence how I think about music. + +(02:33) "Are there any open source musical management sample libraries +that could be used?" Good question, I'm sure there are, I don't know +any of that integrate really well with Emacs. One of the cool things +that I liked about this is that there are no dependencies, you know, +you don't need any external program to generate the music. I mean, it +does shell out to to play, but that should be able to be done on any +operating system, as always, you have something that can play WAVE +files, but yeah, it is interesting to kind of try the different sounds +and different tones that you could get with different instruments. + +(03:14) Have I written any actual songs? Nothing super well put +together, I kind of just been playing around with this. It's kind of… +making this was one of those things where once I made it, I was like, +okay, now I can play with it, and I did a little bit, and was like, I +don't know if I feel like it right now. You know, which I've found +that to be the case with some things that I've implemented in Emacs +where it's… I make it, and then it's the kind of some of the desire to +use it all the time goes away, but I'm sure I'll circle back around at +some point especially kind of maybe once I add in different tones or +something. + +(03:54) I guess a similar question for pre-recorded sounds. Yeah, I +mean, if it's… part of what I did, what I wrote was a WAVE generation +library, so, if you kind of have the data, you could use those and +chop them up and take certain lengths of them and make a WAVE file, so +it's not plug and play right now, but you could certainly add those +notes to do it. + +(04:19) "Any MIDI mapping possibilities?" I haven't looked into it, +but I'm sure you definitely could output to MIDI which is another +benefit of having that multiple layers with the top layer is just, you +know, if the root note is this, we're just two semitones up or seven +semitones up or whatever it is. It should be relatively simple to +kind of switch out that layer underneath from WAVE to MIDI or other +things. + +(04:44) "What were some of the challenges with writing a special mode +for Emacs?" Interested in getting into this, not sure where to start. +This isn't the first mode I've written, so that's right…, certainly +that helps. I actually… I have a video that we recorded it as part of +EmacsNYC on making a major mode. That's basically starts from +nothing, and kind of builds up to an implementation of tic-tac-toe, +but so it kind of goes into printing things out and buttons and making +the mode. I mean, one of the best parts about Emacs is, because it's +so configurable and so introspectible, you can start pretty simply, +and just kind of ask Emacs about things, and then make one little +change. It's really… it's not that bad, so, I'll try to throw a link +up on that page I put up, or please email me for whoever asked this +question to get a link to that video, or just look at the source code +of this or any other major mode. Emacs makes it pretty easy to extend +major modes. + +(05:54) And I think that's the last question in the Etherpad, so, +thanks so much everybody for coming. (Amin: Thank you so much to +Zachary for your awesome talk, and for doing live questions. Thank +you.) Thank you. (Amin: Cheers.) + +<!-- /transcript --> |