music21 v.5 is PYTHON 3 ONLY
Do not upgrade to this version if you are using Python 2.7 (or better still, upgrade yourself to Python 3.6 instead). It runs on Python 3.4-3.6 only. music21 v.4 is the last version to support Python 2.
run "pip3 install music21" to install.
music21 v.5 brings with it seven months of determined work by an open-source team to streamline music analysis. The move to Python 3 allowed us to greatly simplify the codebase and to speed up many commonly used features in music21. If you are apprehensive about switching to Python 3, I hope you'll be convinced that it is worth it the first time you run chordify() on a large score v.5. and see that what might have taken an hour can now be done in few seconds. A great number of bugs involving working with non-English text have been fixed.
As a new major release, music21 breaks backwards compatibility where necessary and deprecates underused functions and things that can be done better in other ways. We're always trying to balance bringing new features with keeping the software as simple to use as possible.
Major changes:
Python 3 only. Yes, I said that but I'm saying it again. This change has made developing much faster and a lot more fun. Also it's made music21 more powerful and faster.
Chordify moves from O(n^2) to O(n) time -- Chordify on large scores works great now.
MusicXML roundtrip now preserves much about appearance, style, metadata, etc. -- you can now load a musicxml file into music21 and back into your software and 90% of the time you'll get visually the same result as the original software. Finale roundtrip is especially good!
Corpora searching is much better and much faster. Metadata is stored in pickle format.
Feature Extraction runs multicore by default. Together with the average of 10x faster chordify, feature extraction on large datasets on multicore systems is now very strong. Parallel processing is easier and much better documented.
Features with JSymbolic equivalents much more closely match the spec and new features have been added (thanks Micah Walter!)
Many routines that used to return string filepaths now return pathlib.Path objects. Especially useful for people running on Python 3.6
Almost all functions deprecated in v. 4 have been removed.
Many keyword functions now require the keyword, so instead of makeNotation(True), call makeNotation(inPlace=True), since explicit is better than implicit, this is a good way of being sure that only the right arguments are being changed.
parsing of Volpiano (Gregorian chant notation) added.
RehearsalMarks are now supported internally and in MusicXML reading/writing.
Other musicXML improvements: Volume of individual notes is now imported and exported. Glissandi and barlines and transposition work better. More elements can be hidden. Empty spaces in MusicXML measures are converted to hidden rests, to avoid gapped streams. Pitches in chords on musicxml import are always sorted from lowest to highest. Fretboard diagrams are supported and Instrument objects have the MusicXML v. 3 sound tags attached. (thanks to Luke Poeppel for these last two)
Corpora improvments: works by Amy Beach, Schubert (Lindebaum), better Bach Chorales (thanks Dr. Norman Schmidt), and Scott Joplin. Errors in various pieces fixed.
Scales and IntervalNetworks run much faster and are better documented.
voiceLeading.VoiceLeadingQuartet improved. compatibility change: improperResolution renamed to isProperResolution and improved. Former title implied that False meant it was proper; now the title reflects the output. Many other fixes and improvements thanks to Ryaan Ahmed.
analysis.transposition -- searches pitch lists for number of distinct transpositions; neoriemannian analysis improvements (thanks to Mark Gotham for both) Stream alignment tools in alpha.analysis (thanks to Emily Zhang)
Copyright and other metadata is preserved in many formats on import. This is just being a good neighbor.
Demos and most alpha code has been moved to a new separate repository:
https://github.com/cuthbertLab/music21-demos -- they will be updated much less frequently. This will also make code development faster. Thanks to all who have contributed to music21's development. We'll be able to get more demos into the codebase by not needing to update them at every moment.
Bugs fixed: chords not in voices in measures with voices were not found in some routines. Instrument objects without midiProgram explicitly set get a program on MIDI output. MIDI no longer inserts a rest at the beginning (thanks KKONZ). Chord.normalOrder fixed (thanks luiselroquero), bugs in Capella parsing. Bugs related to Apple File System High Sierra not sorting files by default. Accented braille characters are exported properly.
Docs can be downloaded as a separate zip file.
I have no major backward-incompatable plans for the near future, so I expect v.5 to have a longer life than the last few releases (at least 18 months, and possibly 2-3 years), but work will continue on smaller subreleases to come. Thanks again to MIT, School of Humanities, Arts, and Social Sciences, and the Music and Theater Arts section for their support of music21 and the Seaver Institute and the National Endowment for the Humanities for financial support.
