.sm

.sm is one of the many file formats used to load a chart in StepMania. This is the most basic format which lists the song information, and background and BPM data at the beginning, and after that lists the chart data in the file.

This format since then has been succeeded by .ssc, which only works on SM5 and has more features that are exclusive such as scroll and speed sections, and fake sections.

How each note type is represented

 * 1 - Tap note
 * 2 - Hold head
 * 3 - Hold/roll end
 * 4 - Roll head
 * M - Mine
 * L - Lift
 * F - Fake
 * A - Attack note
 * K - Auto keysound
 * N - Minefield/"mine hold" head (unused; inert in the codebase and it's a note type used in iDance and StepManiaX)
 * H - Hidden note (only works in SM 3.9+ and AMX)