fumen-measure-analyze/.gemini/tja-spec.md

TJA Format Specification (Rigorous)

1. File Structure

• Extension: .tja
• Encoding: UTF-8 (with BOM) or Shift-JIS.
• Comments: // (inline, until end of line).
• Sections:
  1. Global Metadata: Before any #START.
  2. Course Data: Metadata specific to a difficulty (can be mixed with global).
  3. Song Notation: Between #START and #END.

2. Metadata (Key: Value)

Key	Type	Description
TITLE	string	Song title.
BPM	float	Beats Per Minute. Default: 120.
WAVE	string	Path to audio file.
OFFSET	float	Seconds. Negative delays notes, positive advances them.
DEMOSTART	float	Preview start time in seconds.
GENRE	string	Category (e.g., アニメ, ゲームミュージック).
SCOREMODE	0, 1, 2	Scoring method. Default: 1.
COURSE	enum	0:Easy, 1:Normal, 2:Hard, 3:Oni, 4:Edit/Ura, 5:Tower, 6:Dan.
LEVEL	int	1-10 (Stars).
BALLOON	int[]	Comma-separated hit counts for balloon/kusudama notes.
SCOREINIT	int	Initial score per note.
SCOREDIFF	int	Added score for combo milestones.

3. Song Notation: Notes

Code	Name	Description
0	Blank	No note.
1	Don	Small Red.
2	Ka	Small Blue.
3	DON	Large Red.
4	KA	Large Blue.
5	Drumroll	Start of small drumroll. Ends with 8.
6	DRUMROLL	Start of large drumroll. Ends with 8.
7	Balloon	Start of balloon. Ends with 8.
8	End	Ends 5, 6, 7, or 9.
9	Kusudama	Large balloon/Kusudama. Ends with 8 or 9.
A	DON(H)	Large Red (Hands/Multiplayer).
B	KA(H)	Large Blue (Hands/Multiplayer).

4. Commands (#COMMAND [value])

Command	Value	Description
#START	(P1/P2)	Begin notation.
#END	-	End notation.
#MEASURE	n/d	Set time signature (e.g., 4/4).
#BPMCHANGE	float	Change BPM.
#DELAY	float	Delay in seconds (can be negative).
#SCROLL	float	Multiplier for note scroll speed.
#GOGOSTART	-	Start Go-Go Time (1.2x score).
#GOGOEND	-	End Go-Go Time.
#SECTION	-	Reset branch accuracy counters.
#BRANCHSTART	type,v1,v2	Branching: p (accuracy) or r (drumrolls).
#N, #E, #M	-	Branch paths: Normal, Advanced/Expert, Master.
#BRANCHEND	-	End branching section.
#BARLINEOFF	-	Hide measure lines.
#BARLINEON	-	Show measure lines.
#LYRIC	string	Display lyrics (\n for line break).

5. Logic & Formulas

• Measure Duration (ms): 60000 * (numerator / denominator) * 4 / BPM
• Note Timing: Equally spaced within a measure.
• Branching:
  • p (Percent): (GOOD + OK*0.5) / TotalNotes * 100.
  • Calculated one measure before #BRANCHSTART.