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+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