Minijam

Projects/minijam.md

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+# Minijam : a third-generation generative synth
+
+Relevant links:
+
+* [On Github](https://github.com/jamesmunns/minijam)
+* [Soundcloud] minijam-001 through minijam-007 (3 years ago)
+* Is it also here on [YouTube](https://www.youtube.com/watch?v=7ajO4_6BZ6I)? from 1 year ago (Spring 2022)
+* On Cohost (Chronological, all from around November 2022)
+    * [maybe just little a happy chemicals, as a treat](https://cohost.org/jamesmunns/post/247735-maybe-just-little-a) with Soundcloud sample
+    * [Spec / Music Encoding Notes](https://cohost.org/jamesmunns/post/251210-update-1-the-spec) see below, this post has also more thoughts
+    * [Huh, I guess it works!](https://cohost.org/jamesmunns/post/252694-huh-i-guess-it-work) with link to Minijam on GitHub
+    * [music code progress continues](https://cohost.org/jamesmunns/post/266569-music-code-progress) with code blocks (length, pitch, octave)
+    * [music coding continues](https://cohost.org/jamesmunns/post/273609-music-coding-continu) with progress updates > exporting code for storing musical notes using the [`midly`](https://docs.rs/midly/latest/midly/) crate and the [MuseScore](https://musescore.org/en) music notation program.
+    * [A simpler way to calculate Euclidean Rhythms](https://cohost.org/jamesmunns/post/276695-a-simpler-way-to-cal) with link to GitHub from [padenot](https://github.com/padenot/euclidian-rythms/blob/3c72f37ff8a6c1b7897fdc783e52fabe8eb45dc8/src/lib.rs?utm_source=cohost&utm_medium=iframely#L5-L72)
+    * [Focus thinking](https://cohost.org/jamesmunns/post/286011-focus-thinking) with more open thoughts and theories
+    * [More synth thinking](https://cohost.org/jamesmunns/post/292698-more-synth-thinking) with diagram
+    * [A little more synth progress](https://cohost.org/jamesmunns/post/296675-a-little-more-synth) with code block "probably about half done now"
+    * Latest update> [not totally there, but progress](https://cohost.org/jamesmunns/post/309767-not-totally-there-b) with sheets of music, what was acheived so far, plans for TODOs and improvements
+
+    [Soundcloud]: https://soundcloud.com/james-munns
+
+## Summary
+
+This is a tiny, first attempt at a sequencer for Mnemos.
+
+## Goals
+
+Eventually it should be something bigger (or a part of something bigger), but the goals here are roughly:
+
+* Come up with a way to sequence a single track, with start/end timings, notes, picking different wave types
+* Come up with some way to command (RPC? script?) that track
+* Spread it out to 4-8 tracks simultaneously
+* Come up with a user interface for all that
+
+## Current State
+
+To Do> James
+
+## Open tasks
+
+To Do> James
+
+## Areas of research
+
+To Do> James
+
+## Cross links to related topics/projects
+
+To Do> James
+
+## Note logs
+
+To Do> James
+
+# [The Spec](https://cohost.org/jamesmunns/post/251210-update-1-the-spechttps://cohost.org/jamesmunns/post/251210-update-1-the-spec)
+
+## Music Encoding Notes
+
+The idea is to use variable-length encoding for each of three fields:
+
+* Pitch
+* Starting Beat
+* Note Length
+
+Rests are NOT encoded, only played notes.
+
+This format is intended to be used both as an in-memory format for generating data into a buffer, though it may serve as (part of) a wire format as well.
+
+To do this, let's start with a single variable length primitive. This is roughly based on [varints](https://postcard.jamesmunns.com/wire-format.html#varint-encoded-integers), which I use in [postcard](/Projects/postcard.md).
+
+Note: This is a sketch, not a formal spec proposal.
+
+## `KCint`s
+Let's make a number format that encodes 8 OR 16-bit numbers.
+
+> authors note: 816 is the area code of Kansas City. Since these are 8/16-bit numbers, it made sense to me. Not to be confused with [Kansas City Standard](https://en.wikipedia.org/wiki/Kansas_City_standard).
+
+The shorter, 8-bit variants will look like this:
+
+`[0b0xxx_xxxx]` - One flag bit (zero), and 7 data bits. 0..=127
+
+`[0b1xxx_xxxx, 0byyyy_yyyy]` - One flag bit (one) and 15 data bits, little endian. 0..=32767.
+
+UNLIKE varints, the "continuation" bit only exists in the first, least significant byte, which means we have seven bits of data in one byte, or fifteen bits of data in a two-byte pair.
+
+## Pitch
+
+### 7-bit mode
+
+Here, I'm going to steal a page from [MIDI encoding](https://www.audiolabs-erlangen.de/resources/MIR/FMP/C1/C1S2_MIDI.html) of pitch. Basically, `0` maps to `C0`, which has a freqency of 16.35Hz, and each number basically "walks up the keyboard", or increments the frequency by one semitone. [This table](https://pages.mtu.edu/~suits/notefreqs.html) also shows how the frequencies nonlinearly increase by semitone.
+
+This gives us a frequency range of 16.25Hz (`C0`), up to 25kHz or so (`G10`), which is pretty much beyond the full range of human hearing in both directions.
+
+### 15-bit mode
+
+BUT! You might not want *exactly* a note from the scale! You might be doing something atonal, or may want to use a non-western scale.
+
+For that, the lower 7 bits retain the same meaning as a "base note", and the upper 8 bits encode a linear offset towards the next note.
+
+Let's say we start with `C4`, or `60`, or `0x3C` as our base note:
+
+* `[0x3C]` - C4, 261.63Hz
+* `[0x3D]` - C#4, 277.18Hz
+* `[0xBC, 0x00]`- C4, 00% (000 / 256) to C#4, still 261.63Hz
+* `[0xBC, 0x80]` - C4, 50% (128 / 256) to C#4, 269.41Hz
+* `[0xBC, 0xC0]` - C4, 75% (192 / 256) to C#4, 273.29Hz
+
+I'm not sure linear interpolation is the best choice here, so consider that subject to change.
+
+## Starting Beat
+
+Here, I plan to break blocks (somehow) into 64-quarter-note blocks. This matches 16 bars at a 4:4 time signature.
+
+### 7-bit mode
+
+In 7 bit mode, the starting number represents the index of eighth notes from the start.
+
+This means that `0x00` maps to bar one, eighth note one. `0x7F` maps to bar 16, eighth note eight.
+
+### 15-bit mode
+
+In 15 bit mode, I again steal a page from MIDI and other audio equipment, and use the concep of [Pulses Per Quarter Note](https://en.wikipedia.org/wiki/Pulses_per_quarter_note). This is basically an integer divider for the "resolution" available within a single quarter note.
+
+I plan to use 192 PPQN, which means I can accurately reproduce 64th note offsets as well as 32nd note triplet offsets. That's good enough for me.
+
+This mode also indexes from the start of the 16-bar segment, which means:
+
+* `0x80, 0x00` - (0) is the down beat of the first note of the first bar
+* `0xC0, 0x01` - (192) is the down beat of the second quarter note of the first bar
+* `0xFF, 0x5F` - (12287) is the last 64th note of the 16th bar
+* All values above 12287 are invalid for now (treated as a decode error)
+
+## Length
+
+This is the length the note is to be held.
+
+### 7-bit mode
+
+In 7-bit mode, we use "regular" common note values.
+
+* 0x00 - 32nd note triplet
+* 0x01 - 16th note triplet
+* 0x02 - 8th note triplet
+* 0x03 - quarter note triplet
+* 0x04 - half note triplet
+* 0x05 - 64th note
+* 0x06 - 32nd note
+* 0x07 - 16th note
+* 0x08 - 8th note
+* 0x09..=0x3F - RESERVED (decode error)
+* 0x40..=0x7F - Sustain, quarter note increments (see below)
+
+For values 0x40..=0x7F, the note will be the (number of quarter note beats - 0x3F).
+
+So:
+
+* 0x40 - quarter note
+* 0x41 - half note
+* 0x43 - whole note
+* 0x45 - whole + half
+* 0x47 - two whole
+* 0x7F - 16x whole notes
+
+### 15-bit mode
+
+In 15-bit mode, we go back to 192 PPQN counts. Currently a length of zero is reserved (decode error).
+
+This means:
+
+* `0x80, 0x01` - (1) would be 1/3 of a 64th note
+* `0xC0, 0x01` - (192) would be the same as a quarter note
+* `0xA0, 0x02` - (288) would be a quarter + an eighth
+Anything > 12288 (`192 * 16 * 4`) will be treated as a decode error.
+
+## Framing
+
+Currently, this doesn't tackle the concepts of framing, or how we stitch together 16-bar chunks, or how to do fancy things like repeated blocks, or anything like that. I imagine the format described above will be "wrapped" in some slightly more comprehensive format.

README.md

@@ -18,14 +18,14 @@ The information provided here is for general informational purposes only and is
 
 ## Project Page Organization
 
-Different folders: 
+Different folders:
 
 * Projects
 * Inspiration from others
-* Current Research 
+* Current Research
 * Notes, other material
 
-with these topics 
+with these topics
 
 + Name
 + Summary