WEBVTT 00:00:00.000 --> 00:00:00.956 align:middle line:90% [SQUEAKING] 00:00:00.956 --> 00:00:03.824 align:middle line:90% [RUSTLING] 00:00:03.824 --> 00:00:06.692 align:middle line:90% [CLICKING] 00:00:06.692 --> 00:00:10.040 align:middle line:90% 00:00:10.040 --> 00:00:12.000 align:middle line:84% PROFESSOR: Hi, OpenCourseWare learners. 00:00:12.000 --> 00:00:14.090 align:middle line:84% We've gotten to the part of the first lecture 00:00:14.090 --> 00:00:16.309 align:middle line:84% where the technical difficulties made it 00:00:16.309 --> 00:00:19.110 align:middle line:84% a little too hard to follow what was happening there. 00:00:19.110 --> 00:00:23.000 align:middle line:84% So I'm going to rerecord what we all did 00:00:23.000 --> 00:00:25.400 align:middle line:90% as the opening of the class. 00:00:25.400 --> 00:00:31.110 align:middle line:84% To begin, go ahead and go to the URL on the screen right now. 00:00:31.110 --> 00:00:33.920 align:middle line:84% This is a project from Google called 00:00:33.920 --> 00:00:39.110 align:middle line:84% Colab that allows you to run Python scripts, including 00:00:39.110 --> 00:00:44.300 align:middle line:84% Music21, in your own browser, without installing anything 00:00:44.300 --> 00:00:45.090 align:middle line:90% on your computer. 00:00:45.090 --> 00:00:49.080 align:middle line:84% So go ahead and click this Play button. 00:00:49.080 --> 00:00:51.380 align:middle line:84% You're going to see a warning that Google 00:00:51.380 --> 00:00:52.770 align:middle line:90% didn't write this notebook. 00:00:52.770 --> 00:00:54.230 align:middle line:90% I did. 00:00:54.230 --> 00:00:56.940 align:middle line:90% I think it's pretty safe. 00:00:56.940 --> 00:01:00.940 align:middle line:84% What it does is it installs the latest version of Music21, 00:01:00.940 --> 00:01:04.780 align:middle line:84% and MuseScore, and some other software needed 00:01:04.780 --> 00:01:08.800 align:middle line:84% to run some of the tools we're going to be using, 00:01:08.800 --> 00:01:12.040 align:middle line:84% without installing Python on your computer. 00:01:12.040 --> 00:01:14.930 align:middle line:84% Google already has a copy of Music21, 00:01:14.930 --> 00:01:20.800 align:middle line:84% but this just brings you to the latest version. 00:01:20.800 --> 00:01:24.580 align:middle line:84% And go ahead and pause, and we'll come back 00:01:24.580 --> 00:01:26.210 align:middle line:90% after it's all installed. 00:01:26.210 --> 00:01:33.160 align:middle line:90% 00:01:33.160 --> 00:01:34.280 align:middle line:90% Welcome back. 00:01:34.280 --> 00:01:38.420 align:middle line:84% I hope that these cells aren't running anymore. 00:01:38.420 --> 00:01:40.310 align:middle line:90% So we can start coming in. 00:01:40.310 --> 00:01:42.580 align:middle line:84% If you've never used Jupyter Notebook 00:01:42.580 --> 00:01:44.930 align:middle line:84% or another online collaborative environment, 00:01:44.930 --> 00:01:47.050 align:middle line:84% the important thing that you're going to need 00:01:47.050 --> 00:01:49.100 align:middle line:84% is to be clicking into these cells. 00:01:49.100 --> 00:01:50.840 align:middle line:84% The gray ones are where you type. 00:01:50.840 --> 00:01:54.190 align:middle line:84% And the ones with the white or black background 00:01:54.190 --> 00:01:57.560 align:middle line:84% are the ones where output's coming out. 00:01:57.560 --> 00:02:02.440 align:middle line:84% In order to run a cell, you just type Shift and Return 00:02:02.440 --> 00:02:03.680 align:middle line:90% or Shift and Enter. 00:02:03.680 --> 00:02:05.380 align:middle line:84% So what we're going to do is I'm just 00:02:05.380 --> 00:02:09.350 align:middle line:84% going to click into this cell and hit Shift Enter. 00:02:09.350 --> 00:02:12.800 align:middle line:84% And this will make sure that Music21 actually works. 00:02:12.800 --> 00:02:17.260 align:middle line:84% Sometimes the first time you show a score 00:02:17.260 --> 00:02:19.190 align:middle line:90% it doesn't work as well. 00:02:19.190 --> 00:02:21.410 align:middle line:84% And on some browsers, this will work. 00:02:21.410 --> 00:02:23.470 align:middle line:90% You can listen to a score. 00:02:23.470 --> 00:02:27.595 align:middle line:84% And let's see if this works or not. 00:02:27.595 --> 00:02:28.780 align:middle line:90% [TONE] 00:02:28.780 --> 00:02:30.040 align:middle line:90% There we go. 00:02:30.040 --> 00:02:32.850 align:middle line:84% And now we're ready to actually begin. 00:02:32.850 --> 00:02:34.600 align:middle line:84% We're not going to generate with AI today. 00:02:34.600 --> 00:02:37.570 align:middle line:90% We'll write our own scores. 00:02:37.570 --> 00:02:39.610 align:middle line:84% So if you're with me, we're going 00:02:39.610 --> 00:02:42.820 align:middle line:84% to start anything where you're doing a Python 00:02:42.820 --> 00:02:46.190 align:middle line:84% session by importing the code that's useful. 00:02:46.190 --> 00:02:49.460 align:middle line:84% And for this one, it's the Music21 toolkit. 00:02:49.460 --> 00:02:51.860 align:middle line:84% So we're going to import everything from it. 00:02:51.860 --> 00:02:55.150 align:middle line:84% If you're somebody who's done a lot of Python 00:02:55.150 --> 00:02:58.520 align:middle line:84% and cares about things like polluting your namespace, 00:02:58.520 --> 00:03:00.400 align:middle line:90% you can do individual modules. 00:03:00.400 --> 00:03:03.330 align:middle line:84% But I'm always going to do it as if we have all the parts 00:03:03.330 --> 00:03:08.370 align:middle line:90% of Music21 at your fingertips. 00:03:08.370 --> 00:03:13.330 align:middle line:84% So we're going to load a chorale by Johann Sebastian Bach. 00:03:13.330 --> 00:03:17.260 align:middle line:84% It's his shortest chorale, called BWV66.6. 00:03:17.260 --> 00:03:19.720 align:middle line:84% So first, I'll create a variable, call it Bach. 00:03:19.720 --> 00:03:25.140 align:middle line:84% And we'll use the corpus tool from Music21 and its parse 00:03:25.140 --> 00:03:30.786 align:middle line:84% function to load in bach/bwv66.6. 00:03:30.786 --> 00:03:32.440 align:middle line:90% And I'll hit Shift Enter. 00:03:32.440 --> 00:03:34.240 align:middle line:90% And it's assigned to Bach. 00:03:34.240 --> 00:03:40.000 align:middle line:84% And we can call the method show on it to see the score of that. 00:03:40.000 --> 00:03:43.630 align:middle line:84% Yep, looks like a chorale by Bach. 00:03:43.630 --> 00:03:46.930 align:middle line:84% And you can see that has soprano, alto, tenor, bass. 00:03:46.930 --> 00:03:52.600 align:middle line:84% And we can get the alto part by saying bach.parts, 00:03:52.600 --> 00:03:55.780 align:middle line:90% square brackets, open, alto. 00:03:55.780 --> 00:03:57.785 align:middle line:90% And we'll just show that. 00:03:57.785 --> 00:04:01.840 align:middle line:90% 00:04:01.840 --> 00:04:02.500 align:middle line:90% Yes. 00:04:02.500 --> 00:04:04.690 align:middle line:90% Looks like the alto part. 00:04:04.690 --> 00:04:07.420 align:middle line:84% Now let's get the soprano part and assign it 00:04:07.420 --> 00:04:10.010 align:middle line:90% to a variable sopr for soprano. 00:04:10.010 --> 00:04:11.440 align:middle line:90% And we'll just do that. 00:04:11.440 --> 00:04:15.590 align:middle line:84% Instead, this time we'll get it by doing the part number. 00:04:15.590 --> 00:04:17.660 align:middle line:90% And so it's the first part. 00:04:17.660 --> 00:04:21.950 align:middle line:84% And so in Python, that means it's part 0, parts 0. 00:04:21.950 --> 00:04:27.130 align:middle line:84% And one of the things that we do in Music21 00:04:27.130 --> 00:04:31.010 align:middle line:84% is when something is in a programmer's rule, 00:04:31.010 --> 00:04:35.080 align:middle line:84% we follow the conventions of programming, 00:04:35.080 --> 00:04:37.010 align:middle line:90% where everything starts with 0. 00:04:37.010 --> 00:04:39.063 align:middle line:84% And when we're in musician space, 00:04:39.063 --> 00:04:40.480 align:middle line:84% such as talking about measures, we 00:04:40.480 --> 00:04:43.570 align:middle line:84% don't subtract 1 from the measure number or anything 00:04:43.570 --> 00:04:44.420 align:middle line:90% like that. 00:04:44.420 --> 00:04:49.870 align:middle line:84% So if we wanted to just see measures 3 through 5, inclusive 00:04:49.870 --> 00:04:55.120 align:middle line:84% of the soprano part, we could do something like that. 00:04:55.120 --> 00:04:57.400 align:middle line:90% Oops. 00:04:57.400 --> 00:05:01.410 align:middle line:84% Or we could type the word measures properly. 00:05:01.410 --> 00:05:04.520 align:middle line:90% And then we'll get that measure. 00:05:04.520 --> 00:05:05.820 align:middle line:90% Just gets a single measure. 00:05:05.820 --> 00:05:06.720 align:middle line:90% This one got that. 00:05:06.720 --> 00:05:07.370 align:middle line:90% Great. 00:05:07.370 --> 00:05:11.030 align:middle line:84% And in fact, we'll use the measure thing now. 00:05:11.030 --> 00:05:15.110 align:middle line:84% And we'll get in measure five, the zeroth, first, second note, 00:05:15.110 --> 00:05:16.860 align:middle line:90% the one with the fermata on it. 00:05:16.860 --> 00:05:20.270 align:middle line:84% And so we'll call it C because it's a C. Actually, 00:05:20.270 --> 00:05:21.240 align:middle line:90% it's a C sharp. 00:05:21.240 --> 00:05:24.600 align:middle line:90% But we'll see why not. 00:05:24.600 --> 00:05:28.490 align:middle line:90% And so we'll get notes number 2. 00:05:28.490 --> 00:05:31.850 align:middle line:84% If we called it C sharp, then everything after this 00:05:31.850 --> 00:05:32.665 align:middle line:90% would be a comment. 00:05:32.665 --> 00:05:33.540 align:middle line:90% So that doesn't work. 00:05:33.540 --> 00:05:36.290 align:middle line:84% So we'll just call it C. And now what 00:05:36.290 --> 00:05:40.760 align:middle line:84% we can do is manipulate it, change its style, 00:05:40.760 --> 00:05:43.580 align:middle line:90% its color to red. 00:05:43.580 --> 00:05:48.050 align:middle line:84% And now when I show the soprano part, because they're all linked 00:05:48.050 --> 00:05:50.130 align:middle line:90% to each other, we should see-- 00:05:50.130 --> 00:05:52.195 align:middle line:84% yep, there's a note that's in red. 00:05:52.195 --> 00:05:55.940 align:middle line:90% 00:05:55.940 --> 00:05:58.820 align:middle line:84% So that's how we can manipulate a score. 00:05:58.820 --> 00:06:03.910 align:middle line:84% And now let's see how we can do some analytical functions 00:06:03.910 --> 00:06:04.610 align:middle line:90% on things. 00:06:04.610 --> 00:06:06.860 align:middle line:90% So let's do Bach to analyze. 00:06:06.860 --> 00:06:10.990 align:middle line:84% And we'll analyze the key of the piece. 00:06:10.990 --> 00:06:13.540 align:middle line:84% And it says it returns a key object that 00:06:13.540 --> 00:06:15.410 align:middle line:90% says it's in F sharp minor. 00:06:15.410 --> 00:06:17.590 align:middle line:84% And one of the things I really want to emphasize 00:06:17.590 --> 00:06:20.450 align:middle line:84% is always go back and do the smell test. 00:06:20.450 --> 00:06:23.630 align:middle line:84% Is this true, or does it look like baloney? 00:06:23.630 --> 00:06:26.890 align:middle line:84% And we can see, well, begins on A, 00:06:26.890 --> 00:06:29.000 align:middle line:90% but it does have three sharps. 00:06:29.000 --> 00:06:32.600 align:middle line:84% And at the end, yep, there is an F sharp in the bass. 00:06:32.600 --> 00:06:36.910 align:middle line:84% Though, it looks kind of like F major, but-- 00:06:36.910 --> 00:06:38.650 align:middle line:90% OK, here some F minor. 00:06:38.650 --> 00:06:41.770 align:middle line:84% OK, it kind of passes the smell tests. 00:06:41.770 --> 00:06:44.690 align:middle line:84% And we'll see why that's so important in just a little bit. 00:06:44.690 --> 00:06:48.080 align:middle line:84% But it did seem like it was beginning in A. 00:06:48.080 --> 00:06:50.660 align:middle line:84% So we can just analyze a portion of that. 00:06:50.660 --> 00:06:55.780 align:middle line:84% So we'll do bach measures 0, because we want the pickup 00:06:55.780 --> 00:06:57.640 align:middle line:90% measure, and 2. 00:06:57.640 --> 00:07:01.745 align:middle line:84% And we'll analyze the key of just that passage. 00:07:01.745 --> 00:07:04.180 align:middle line:84% Ah, does seem to start in A major. 00:07:04.180 --> 00:07:07.280 align:middle line:90% 00:07:07.280 --> 00:07:09.150 align:middle line:84% Let's do something that seems pretty simple. 00:07:09.150 --> 00:07:11.510 align:middle line:84% Let's count the number of notes in the piece. 00:07:11.510 --> 00:07:15.300 align:middle line:84% So we can just do len bach.notes. 00:07:15.300 --> 00:07:17.750 align:middle line:84% That just gets all the notes of the piece. 00:07:17.750 --> 00:07:20.470 align:middle line:84% In another language, it would be bach.notes.length. 00:07:20.470 --> 00:07:24.765 align:middle line:90% 00:07:24.765 --> 00:07:26.640 align:middle line:84% I don't know how many notes are in the piece, 00:07:26.640 --> 00:07:29.040 align:middle line:84% but I'm pretty sure it's more than 0. 00:07:29.040 --> 00:07:33.110 align:middle line:84% And the reason for this is that Music21 00:07:33.110 --> 00:07:37.370 align:middle line:84% and most ways of conceiving music on the computer 00:07:37.370 --> 00:07:39.780 align:middle line:84% don't think of the score as having notes. 00:07:39.780 --> 00:07:41.370 align:middle line:90% The score has parts. 00:07:41.370 --> 00:07:42.980 align:middle line:90% The parts have measures. 00:07:42.980 --> 00:07:45.090 align:middle line:90% And the measures have notes. 00:07:45.090 --> 00:07:49.730 align:middle line:84% So what we could do is get the length of bach parts 00:07:49.730 --> 00:07:55.770 align:middle line:84% 1, measure 2, dot notes, and see, OK, 00:07:55.770 --> 00:07:57.660 align:middle line:90% that passes the smell test. 00:07:57.660 --> 00:08:00.300 align:middle line:84% So what we can do instead is we can 00:08:00.300 --> 00:08:01.660 align:middle line:90% use something called recurse. 00:08:01.660 --> 00:08:05.460 align:middle line:90% So we'll get the bach.recurse. 00:08:05.460 --> 00:08:07.510 align:middle line:90% That's a function, or a method. 00:08:07.510 --> 00:08:10.060 align:middle line:90% And we get the notes on that. 00:08:10.060 --> 00:08:12.870 align:middle line:84% And what recurse says is, open up every box. 00:08:12.870 --> 00:08:14.140 align:middle line:90% You get to a part. 00:08:14.140 --> 00:08:14.950 align:middle line:90% Open it up. 00:08:14.950 --> 00:08:16.270 align:middle line:90% Look inside for measures. 00:08:16.270 --> 00:08:20.070 align:middle line:84% Open it up and keep going until you find notes. 00:08:20.070 --> 00:08:21.880 align:middle line:90% And 165 notes. 00:08:21.880 --> 00:08:26.310 align:middle line:84% That seems to pass the smell test to me. 00:08:26.310 --> 00:08:28.380 align:middle line:84% Right now we've been working with this 00:08:28.380 --> 00:08:32.200 align:middle line:84% as a series of parts that are not connected to each other. 00:08:32.200 --> 00:08:35.320 align:middle line:84% But of course, there are chords in there also. 00:08:35.320 --> 00:08:38.738 align:middle line:90% But if we do bach.-- 00:08:38.738 --> 00:08:41.980 align:middle line:84% and here's another way you can say recurse. 00:08:41.980 --> 00:08:45.060 align:middle line:84% I want to recurse and get everything that's a chord. 00:08:45.060 --> 00:08:47.380 align:middle line:84% There are no chords in this piece. 00:08:47.380 --> 00:08:51.700 align:middle line:84% So we have to create some chords using the chordify method. 00:08:51.700 --> 00:08:56.550 align:middle line:84% So we'll say chor, for chords, equals bach.chordify. 00:08:56.550 --> 00:08:59.470 align:middle line:90% 00:08:59.470 --> 00:09:06.635 align:middle line:84% And now if we show the chordify method-- 00:09:06.635 --> 00:09:08.260 align:middle line:84% And we can see that some of these notes 00:09:08.260 --> 00:09:10.400 align:middle line:84% are way too low to be read properly. 00:09:10.400 --> 00:09:12.230 align:middle line:84% And they have duplicated notes and things. 00:09:12.230 --> 00:09:14.000 align:middle line:84% And over the course of the semester, 00:09:14.000 --> 00:09:19.070 align:middle line:84% we'll find ways that we can make this a lot more representable, 00:09:19.070 --> 00:09:22.000 align:middle line:84% including things like getting rid of passing 00:09:22.000 --> 00:09:25.850 align:middle line:84% tones and other things that disturb looking at the chords. 00:09:25.850 --> 00:09:31.330 align:middle line:84% But for now, we can look at chor for the chords, the number 00:09:31.330 --> 00:09:35.320 align:middle line:84% of chords in that, and see that, yep, that 00:09:35.320 --> 00:09:37.870 align:middle line:90% looks like a reasonable number. 00:09:37.870 --> 00:09:40.570 align:middle line:84% So I hope that gives you a taste of some 00:09:40.570 --> 00:09:43.750 align:middle line:84% of what we're going to be doing over the course of the semester 00:09:43.750 --> 00:09:46.540 align:middle line:90% of this class. 00:09:46.540 --> 00:09:50.360 align:middle line:84% Now, we've gone very fast through a bunch of things, 00:09:50.360 --> 00:09:52.030 align:middle line:84% but don't worry, because we're going 00:09:52.030 --> 00:09:53.870 align:middle line:90% to lock all those things up. 00:09:53.870 --> 00:09:56.240 align:middle line:84% Choridfy is going to be locked up. 00:09:56.240 --> 00:09:58.860 align:middle line:84% And now Analyze Key is going to be locked up. 00:09:58.860 --> 00:10:00.060 align:middle line:90% And what does that mean? 00:10:00.060 --> 00:10:03.470 align:middle line:84% That means that it won't be available to be 00:10:03.470 --> 00:10:07.590 align:middle line:84% used in the rest of the class until it's unlocked again. 00:10:07.590 --> 00:10:09.530 align:middle line:84% The way this class is going to work 00:10:09.530 --> 00:10:11.820 align:middle line:84% is all of these analytical tools, 00:10:11.820 --> 00:10:15.170 align:middle line:84% all these ways of conceiving a score, 00:10:15.170 --> 00:10:18.030 align:middle line:90% will begin by being locked. 00:10:18.030 --> 00:10:22.910 align:middle line:84% And then you'll do an assignment either as a problem set 00:10:22.910 --> 00:10:27.680 align:middle line:84% or as an in-class assignment, where we'll figure out, 00:10:27.680 --> 00:10:29.160 align:middle line:90% How does this work? 00:10:29.160 --> 00:10:31.020 align:middle line:90% What are the ways of doing this? 00:10:31.020 --> 00:10:34.370 align:middle line:84% And then once you've designed your own algorithm 00:10:34.370 --> 00:10:37.100 align:middle line:84% for doing these things, you can either 00:10:37.100 --> 00:10:39.380 align:middle line:84% continue to use your own algorithm, 00:10:39.380 --> 00:10:43.400 align:middle line:84% or you will have unlocked the Music21 version 00:10:43.400 --> 00:10:44.190 align:middle line:90% of the algorithm. 00:10:44.190 --> 00:10:46.898 align:middle line:84% And from then on, you can use that instead. 00:10:46.898 --> 00:10:48.440 align:middle line:84% So we're going to just be building up 00:10:48.440 --> 00:10:54.050 align:middle line:84% knowledge little by little until we have everything. 00:10:54.050 --> 00:10:57.550 align:middle line:84% One of the things that as an OpenCourseWare learner 00:10:57.550 --> 00:11:02.770 align:middle line:84% you won't have access to is the extremely valuable things 00:11:02.770 --> 00:11:04.850 align:middle line:90% that happened outside of class. 00:11:04.850 --> 00:11:07.480 align:middle line:84% Yes, coming to office hours, but mostly 00:11:07.480 --> 00:11:10.070 align:middle line:84% with students helping each other, 00:11:10.070 --> 00:11:13.330 align:middle line:84% giving each other inspiration for projects they could do, 00:11:13.330 --> 00:11:16.210 align:middle line:84% and helping them through some of the more difficult parts 00:11:16.210 --> 00:11:17.300 align:middle line:90% of the class. 00:11:17.300 --> 00:11:20.920 align:middle line:84% So I encourage you, if you can find somebody 00:11:20.920 --> 00:11:23.750 align:middle line:84% else online who's also taking the course, 00:11:23.750 --> 00:11:27.740 align:middle line:84% or somebody who has taken it in the past, and get to know them, 00:11:27.740 --> 00:11:30.310 align:middle line:84% that will give you a lot more of the experience 00:11:30.310 --> 00:11:32.980 align:middle line:84% that the students had at MIT when they were 00:11:32.980 --> 00:11:36.340 align:middle line:90% taking the class in person. 00:11:36.340 --> 00:11:39.220 align:middle line:84% I'm so glad that you've chosen to take your time 00:11:39.220 --> 00:11:44.380 align:middle line:84% to learn about the fascinating world of music theory and music 00:11:44.380 --> 00:11:46.520 align:middle line:90% analysis with a computer. 00:11:46.520 --> 00:11:48.790 align:middle line:84% And I look forward to seeing you again from time 00:11:48.790 --> 00:11:51.360 align:middle line:90% to time in this course. 00:11:51.360 --> 00:11:57.000 align:middle line:90%