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https://github.com/jacoby6000/maestro-midi
Just parses midi files. Nothing fancy. Useful if you want to do some stuff with a midi file.
https://github.com/jacoby6000/maestro-midi
Last synced: 25 days ago
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Just parses midi files. Nothing fancy. Useful if you want to do some stuff with a midi file.
- Host: GitHub
- URL: https://github.com/jacoby6000/maestro-midi
- Owner: Jacoby6000
- License: mit
- Created: 2017-08-03T17:45:19.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2017-08-22T23:08:47.000Z (over 7 years ago)
- Last Synced: 2024-10-22T13:49:39.974Z (2 months ago)
- Language: Scala
- Size: 248 KB
- Stars: 1
- Watchers: 2
- Forks: 2
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
## Maestro Midi
Just some simple tools for parsing midi files. Maestro Midi does nothing to infer or coerce the midi
file in any way. It'll give you a format mirroring 1:1 with the file that was provided.
## Usage
Add as a dependency with
```scala
libraryDependencies += "com.github.jacoby6000" %% "maestro-midi" % "0.1.1"
```
Then use:
```scala
import com.github.jacoby6000.maestro.midi._
import java.nio.file.Files
import java.nio.file.Paths
val midiData: Either[scodec.Err, StandardMidi] = decodeMidi(Files.readAllBytes(Paths.get("path/to/midi/file.mid")))
```
`decodeMidi` is overloaded to work for `Array[Byte]`, `scodec.BitVector`, and `scodec.ByteVector`.
## Understanding
To make use of this library, it is best to have some familiarity with [the midi spec](https://www.csie.ntu.edu.tw/~r92092/ref/midi/).
This library will handle things like "Running Status" for you, and everything else is just mapped to
the events that you will read in the specification.
Some consequences of the structure returned being a mirror of the file, is that there are some
events which you might not expect. `NoteOn(channel, pitch, velocity = 0)` is exactly the same as
`NoteOff(channel, pitch, 40)` and many applications will export midi using `NoteOn` actions
with `velocity` set to `0` instead of `NoteOff` actions. This helps shorten the midi file because of
the whole "Running Status" thing. `midiFile.normalizeOnOff` will fix this and give you what
you probably expect. `midiFile.denormalizeOnOff` will do the opposite.
## Extensions
If you read the specification, you'll note that the Midi specification leaves room for custom
events. To use these, just create a `midi.extensions.MidiExtension` instance, and then run
`decodeMidiExtended(bytes, extension)` to get an instance of a midi file with the extension events
properly decoded. I don't currently have any of these, because I've only ever needed standard midi
events. If you come up with one, let me know and I'll add some docs around it.
## Caveats
If you hold on to instances of `midi.decode.fileCodec`, be wary that the individual instances are
_not_ thread safe. This is because I'm bad and the way way I'm dealing with "Running Status" in the
`eventCodec` uses state. If you parallelize on calls to `midi.decodeMidi` you will be fine,
however. Each call to `decodeMidi` gets its own instance of `midi.decode.fileCodec`.
### Extras
Monocle Lense Library
```
libraryDependencies += "com.github.jacoby6000" %% "maestro-midi-lenses" % "0.1.1"
```