About this specification - Chart specification

This specification defines the song folders that rhythm games such as Clone Hero and YARG play, and the files inside them. A song folder holds the song’s chart, written as a .chart file or a .mid file, a song.ini file with its metadata and chart parsing settings, and its audio and album art. It’s written for two groups of people:

charters, who want to know exactly what each part of a file does, and how to write it;
developers of programs that scan or export song folders, such as games, chart editors, converters and chart sites.

Requirements

Two words carry the requirements:

Must marks a requirement. A file that breaks one is invalid, and a scanner may reject it.
Should marks a recommendation. A file that doesn’t follow one is still valid.

For each requirement a file can break, the page says what each scanner does with the file. Where a hash depends on it, the page also says what a scanner does, so that even an invalid file hashes the same everywhere.

Terms

These words have one meaning throughout the specification, except where the table gives a second:

Term	Meaning
Scanner	Code that scans for song folders and reads their files, such as a game, a chart site, or a library like scan-chart.
Exporter	Code that exports song folders, such as a chart editor or a converter.
Tick	The unit of position in a chart. A chart’s events are placed at whole ticks.
Resolution	The number of ticks in a beat, which is a quarter note.
Track	One instrument at one difficulty, such as Expert guitar. A `.chart` file writes each track as a section. A `.mid` file writes all of an instrument’s difficulties in one MIDI track. The `.mid` pages call a MIDI track a track, as the MIDI standard does.
Event	One line of a `.chart` section, or one MIDI event: a note, a modifier, a phrase, a tempo marker, or a text event.