path: root/2020/subtitles/emacsconf-2020--35-waveing-at-repetitive-repetitive-repetitive-music-zmusic--zachary-kanfer-autogen.vtt

WEBVTT

00:00:04.080 --> 00:00:04.960
hi

00:00:04.960 --> 00:00:08.559
i'm zachary canfer and this is waving

00:00:08.559 --> 00:00:11.679
and repetitive repetitive repetitive

00:00:11.679 --> 00:00:15.759
music over quarantine i've been bored

00:00:15.759 --> 00:00:18.400
and i found this android app that has a

00:00:18.400 --> 00:00:19.680
bunch of mini games

00:00:19.680 --> 00:00:23.519
one of which lets you compose music

00:00:23.519 --> 00:00:26.640
and it works but i

00:00:26.640 --> 00:00:28.160
want a little bit more functionality

00:00:28.160 --> 00:00:30.720
than it offers it's not very flexible

00:00:30.720 --> 00:00:33.760
so i thought what if i made this

00:00:33.760 --> 00:00:35.360
what and what programs could i make this

00:00:35.360 --> 00:00:37.760
in that are really flexible are really

00:00:37.760 --> 00:00:40.320
customizable

00:00:40.320 --> 00:00:44.239
emacs so i looked into it and

00:00:44.239 --> 00:00:46.320
emacs can play sounds right if you hit

00:00:46.320 --> 00:00:47.840
control g a couple times you'll hear

00:00:47.840 --> 00:00:49.760
like an error tone

00:00:49.760 --> 00:00:51.360
and it turns out that that is actually

00:00:51.360 --> 00:00:54.559
playing a wave file

00:00:54.559 --> 00:00:58.960
but what's a wave file

00:00:58.960 --> 00:01:01.920
well it turns out that wave is a musical

00:01:01.920 --> 00:01:03.440
file format

00:01:03.440 --> 00:01:07.840
or really an annoying file format

00:01:07.840 --> 00:01:12.080
so data in it can be an unsigned integer

00:01:12.080 --> 00:01:15.360
or a science integer it's not consistent

00:01:15.360 --> 00:01:17.920
and it's little ending by default which

00:01:17.920 --> 00:01:20.320
is not the way i like to think about it

00:01:20.320 --> 00:01:23.200
now you can set a wav file to be big

00:01:23.200 --> 00:01:25.200
endian but if you do that

00:01:25.200 --> 00:01:28.640
emacs can't play it so little ending it

00:01:28.640 --> 00:01:30.479
is

00:01:30.479 --> 00:01:33.520
there's also duplicate data fields

00:01:33.520 --> 00:01:35.360
here are some fields that are fine but

00:01:35.360 --> 00:01:36.960
then there's a fourth field that's

00:01:36.960 --> 00:01:38.960
calculated based on multiplying two of

00:01:38.960 --> 00:01:40.799
the other ones together

00:01:40.799 --> 00:01:42.399
and then there's another data field

00:01:42.399 --> 00:01:44.880
that's you multiply those three ones

00:01:44.880 --> 00:01:48.479
together so it's just repetitive and

00:01:48.479 --> 00:01:50.479
unnecessary but you have to do it or

00:01:50.479 --> 00:01:54.159
it's not a valid wave file

00:01:54.159 --> 00:01:56.479
also the last part of the file is

00:01:56.479 --> 00:01:58.159
described as data

00:01:58.159 --> 00:02:01.759
or as one website i found said

00:02:01.759 --> 00:02:05.200
the actual sound data now

00:02:05.200 --> 00:02:06.960
i don't know about you but when i see

00:02:06.960 --> 00:02:09.039
that i think

00:02:09.039 --> 00:02:12.080
what is a data it turns out

00:02:12.080 --> 00:02:15.120
that sound is just a wave and

00:02:15.120 --> 00:02:17.760
the data is just a bunch of measurements

00:02:17.760 --> 00:02:19.120
of the height of that wave forming each

00:02:19.120 --> 00:02:20.400
sample

00:02:20.400 --> 00:02:24.480
so this wave starts at 8 goes 9 11 13

00:02:24.480 --> 00:02:27.840
14 15 and then back down and if you just

00:02:27.840 --> 00:02:29.520
take those measurements those numbers

00:02:29.520 --> 00:02:32.080
put them in a file that's all your data

00:02:32.080 --> 00:02:35.200
is

00:02:35.200 --> 00:02:36.560
all right let's go to a demo of my

00:02:36.560 --> 00:02:38.959
program

00:02:38.959 --> 00:02:41.920
so this is what z music looks like the

00:02:41.920 --> 00:02:44.080
blue highlighted row is a single beat

00:02:44.080 --> 00:02:48.319
there's 16 of them in this z music file

00:02:48.319 --> 00:02:52.000
and each dash in the row

00:02:52.000 --> 00:02:55.040
is a single note increasing starting

00:02:55.040 --> 00:02:57.920
really low all the way on the left and

00:02:57.920 --> 00:02:58.959
going up

00:02:58.959 --> 00:03:01.680
as we go to the right so if we started

00:03:01.680 --> 00:03:02.400
playing

00:03:02.400 --> 00:03:05.040
we won't hear anything but we'll see the

00:03:05.040 --> 00:03:06.400
highlighted beat is the currently

00:03:06.400 --> 00:03:07.680
playing one

00:03:07.680 --> 00:03:11.120
and we see that it loops so we can stop

00:03:11.120 --> 00:03:12.720
it

00:03:12.720 --> 00:03:30.879
and now we can click to add some notes

00:03:30.879 --> 00:03:33.120
even more than one note at the same time

00:03:33.120 --> 00:03:43.920
works

00:03:43.920 --> 00:03:56.160
and we can even add notes while it's

00:03:56.160 --> 00:03:58.840
[Applause]

00:03:58.840 --> 00:04:00.150
playing

00:04:00.150 --> 00:04:08.239
[Applause]

00:04:08.239 --> 00:04:10.480
okay here are some other features that i

00:04:10.480 --> 00:04:12.959
didn't have time to demo

00:04:12.959 --> 00:04:16.000
so you can save the music to a file and

00:04:16.000 --> 00:04:18.239
this is interesting because normally

00:04:18.239 --> 00:04:20.880
if there's no note in a beat we just

00:04:20.880 --> 00:04:22.800
don't play that beat

00:04:22.800 --> 00:04:24.639
but if you're writing to a file you have

00:04:24.639 --> 00:04:25.919
to put something in

00:04:25.919 --> 00:04:27.840
so when it's playing it knows to not

00:04:27.840 --> 00:04:31.360
make a sound there

00:04:31.360 --> 00:04:34.479
we can also use different scales we're

00:04:34.479 --> 00:04:36.240
using the minor pentatonic

00:04:36.240 --> 00:04:38.080
in the demo but you can use the major

00:04:38.080 --> 00:04:39.680
scale the minor scale

00:04:39.680 --> 00:04:42.400
or anything else and there's also

00:04:42.400 --> 00:04:44.400
keyboard support but it sounds really

00:04:44.400 --> 00:04:45.199
bad

00:04:45.199 --> 00:04:48.240
and i'll explain why later

00:04:48.240 --> 00:04:50.800
here are some things i learned while

00:04:50.800 --> 00:04:53.520
writing z music

00:04:53.520 --> 00:04:56.479
emacs has buttons which are great as

00:04:56.479 --> 00:04:58.240
long

00:04:58.240 --> 00:04:59.919
as you don't put two of them right next

00:04:59.919 --> 00:05:02.160
to each other so if you do that

00:05:02.160 --> 00:05:04.400
mousing over one of them highlights both

00:05:04.400 --> 00:05:06.160
of them

00:05:06.160 --> 00:05:07.919
now that's because a button is really

00:05:07.919 --> 00:05:10.080
just a series of characters with a text

00:05:10.080 --> 00:05:11.680
property to highlight them

00:05:11.680 --> 00:05:15.120
so the fix is you put another character

00:05:15.120 --> 00:05:16.479
between the two buttons

00:05:16.479 --> 00:05:18.080
then mousing over one of them only

00:05:18.080 --> 00:05:19.759
highlights the one you want

00:05:19.759 --> 00:05:21.600
but even this doesn't work really great

00:05:21.600 --> 00:05:22.800
for z music

00:05:22.800 --> 00:05:25.440
because the music has a lot of very

00:05:25.440 --> 00:05:27.120
small buttons in a row

00:05:27.120 --> 00:05:29.840
so it's really easy to accidentally put

00:05:29.840 --> 00:05:31.600
your cursor over the space

00:05:31.600 --> 00:05:34.639
and click on that instead of the button

00:05:34.639 --> 00:05:37.120
so i looked into unicode and i found

00:05:37.120 --> 00:05:38.160
this character called

00:05:38.160 --> 00:05:40.800
a zero width space so we should be able

00:05:40.800 --> 00:05:42.560
to put that between buttons and not be

00:05:42.560 --> 00:05:45.120
able to accidentally click on it

00:05:45.120 --> 00:05:46.960
unfortunately a zeroth space isn't

00:05:46.960 --> 00:05:50.080
actually zero width

00:05:50.080 --> 00:05:51.680
if we put a hundred of them between two

00:05:51.680 --> 00:05:53.759
other characters you can see there's

00:05:53.759 --> 00:05:54.880
space there

00:05:54.880 --> 00:05:56.240
and i think what's happening is the

00:05:56.240 --> 00:05:58.160
space is zero width

00:05:58.160 --> 00:06:01.360
but then emax put uses one pixel between

00:06:01.360 --> 00:06:02.800
each pair of characters

00:06:02.800 --> 00:06:08.080
for the cursor so it's almost zero width

00:06:08.080 --> 00:06:09.919
some ways to play sound that don't quite

00:06:09.919 --> 00:06:12.960
work play sound plays music

00:06:12.960 --> 00:06:14.800
but it blocks you can't do things like

00:06:14.800 --> 00:06:17.280
set other notes or even pause the music

00:06:17.280 --> 00:06:19.600
and if you throw it into async.el it's

00:06:19.600 --> 00:06:21.600
silent and i don't know why

00:06:21.600 --> 00:06:24.479
so the solution i went with is taking

00:06:24.479 --> 00:06:25.440
that wav file

00:06:25.440 --> 00:06:27.039
ran into the file system and then

00:06:27.039 --> 00:06:29.199
shelling out to a native executable to

00:06:29.199 --> 00:06:30.639
play the sound

00:06:30.639 --> 00:06:32.880
and that works fine as long as you only

00:06:32.880 --> 00:06:34.240
do it once

00:06:34.240 --> 00:06:36.080
because if you do it a couple times at

00:06:36.080 --> 00:06:37.600
the same time like if you have a chord

00:06:37.600 --> 00:06:38.639
and you want to play three notes

00:06:38.639 --> 00:06:40.000
simultaneously

00:06:40.000 --> 00:06:42.319
you get this weird interference and

00:06:42.319 --> 00:06:43.680
that's actually why the keyboard from

00:06:43.680 --> 00:06:46.319
before didn't work

00:06:46.319 --> 00:06:49.199
also side effects have this unexpected

00:06:49.199 --> 00:06:50.240
impact

00:06:50.240 --> 00:06:53.039
uh when you saw the demo it was running

00:06:53.039 --> 00:06:55.120
pretty smoothly

00:06:55.120 --> 00:06:57.680
but if i just add one message statement

00:06:57.680 --> 00:06:58.479
every beat for

00:06:58.479 --> 00:07:00.960
debugging purposes i was getting lag and

00:07:00.960 --> 00:07:03.759
jitter

00:07:03.759 --> 00:07:05.440
here's the one thing i learned about

00:07:05.440 --> 00:07:08.319
music theory music theory

00:07:08.319 --> 00:07:11.599
is not easy to program

00:07:11.599 --> 00:07:12.880
i was looking around to see what

00:07:12.880 --> 00:07:15.440
concepts we can use to code the scales

00:07:15.440 --> 00:07:16.080
to code the

00:07:16.080 --> 00:07:18.160
notes the first thing that i saw is

00:07:18.160 --> 00:07:20.240
scale degrees

00:07:20.240 --> 00:07:23.360
and this when i looked into it you don't

00:07:23.360 --> 00:07:26.319
want to program in scale degrees

00:07:26.319 --> 00:07:28.240
so you see we have the first second

00:07:28.240 --> 00:07:29.759
third fourth fifth sixth seventh but

00:07:29.759 --> 00:07:32.080
then it wraps around that octave up

00:07:32.080 --> 00:07:33.919
is also a first and that's because both

00:07:33.919 --> 00:07:36.000
of those notes are c

00:07:36.000 --> 00:07:38.479
uh so that didn't work and also you

00:07:38.479 --> 00:07:39.759
couldn't really easily

00:07:39.759 --> 00:07:43.599
specify a flat or sharp you could say

00:07:43.599 --> 00:07:47.680
a sharp third uh or

00:07:47.680 --> 00:07:50.879
you know a flat seventh or whatever but

00:07:50.879 --> 00:07:52.319
then you kind of have these two pieces

00:07:52.319 --> 00:07:53.759
of data that indicate the note and i

00:07:53.759 --> 00:07:55.840
didn't i didn't love that

00:07:55.840 --> 00:07:57.440
so i looked a little looked again and i

00:07:57.440 --> 00:07:59.280
found intervals

00:07:59.280 --> 00:08:01.120
and then i thought about it and you

00:08:01.120 --> 00:08:02.080
don't really want to program in

00:08:02.080 --> 00:08:03.440
intervals either

00:08:03.440 --> 00:08:05.520
it fixes some of the problems with scale

00:08:05.520 --> 00:08:07.039
degrees you see

00:08:07.039 --> 00:08:08.319
all the way on the right you have an

00:08:08.319 --> 00:08:10.319
octave so you wrap to 8 and you

00:08:10.319 --> 00:08:13.039
go 9 10 and that works but you solve the

00:08:13.039 --> 00:08:14.319
same problem you see you have a major

00:08:14.319 --> 00:08:16.400
third but below we also have a minor

00:08:16.400 --> 00:08:18.080
third so you saw that problem of having

00:08:18.080 --> 00:08:20.160
two pieces of information

00:08:20.160 --> 00:08:23.360
uh so i thought about it music's really

00:08:23.360 --> 00:08:27.120
frequencies like an a is 440 hertz

00:08:27.120 --> 00:08:28.400
so at a low level that's what we're

00:08:28.400 --> 00:08:29.360
going to do we're just going to use

00:08:29.360 --> 00:08:30.560
frequencies

00:08:30.560 --> 00:08:32.800
and then at the one level above that uh

00:08:32.800 --> 00:08:34.159
that's a little bit easier for humans to

00:08:34.159 --> 00:08:35.360
think about

00:08:35.360 --> 00:08:37.039
we're going to use semitones up from the

00:08:37.039 --> 00:08:39.519
root which is kind of like scale degrees

00:08:39.519 --> 00:08:40.959
but instead of just counting each note

00:08:40.959 --> 00:08:42.880
as one more we're going to say how many

00:08:42.880 --> 00:08:44.560
semitones up it is

00:08:44.560 --> 00:08:47.200
so if there's a sharp between two notes

00:08:47.200 --> 00:08:48.480
that's going to be two steps up instead

00:08:48.480 --> 00:08:50.000
of just one

00:08:50.000 --> 00:08:51.279
and then we translate those two

00:08:51.279 --> 00:08:54.160
frequencies so your a is 440 hertz

00:08:54.160 --> 00:08:56.920
another note might be

00:08:56.920 --> 00:08:58.480
613.5

00:08:58.480 --> 00:09:00.720
or whatever and we that's we use the low

00:09:00.720 --> 00:09:02.959
level to play

00:09:02.959 --> 00:09:05.200
some future work i have i want to add

00:09:05.200 --> 00:09:06.480
some drums

00:09:06.480 --> 00:09:08.240
i want to make that keyboard actually

00:09:08.240 --> 00:09:09.680
work uh

00:09:09.680 --> 00:09:12.399
and uh computers and synthesizers are

00:09:12.399 --> 00:09:14.320
the only place you hear a pure sine wave

00:09:14.320 --> 00:09:16.000
like the one we have here

00:09:16.000 --> 00:09:17.680
so i want to add overtones or other

00:09:17.680 --> 00:09:19.440
octaves above it uh just to make it

00:09:19.440 --> 00:09:23.120
sound a little bit more realistic

00:09:23.120 --> 00:09:25.360
i've put notes references in the source

00:09:25.360 --> 00:09:28.480
code up at zck dot me slash emacs conf

00:09:28.480 --> 00:09:31.839
2020 i'm one of the organizers of emacs

00:09:31.839 --> 00:09:33.040
nyc

00:09:33.040 --> 00:09:36.080
check that out and if you take a look

00:09:36.080 --> 00:09:38.240
or have any thoughts i'd love to hear

00:09:38.240 --> 00:09:39.839
them and

00:09:39.839 --> 00:09:46.160
thanks so much for coming to my talk