Official Charting Standard (OCS)

Introduction

The Band BoomBox Official Charting Standard is a set of guidelines that provides recommendations and best practices on how song charts (note sequences) should be authored. All "official" songs - namely those included with the game itself - use this standard. The standard has been refined during development of Band BoomBox itself, making it very useful to anyone starting out authoring their own custom songs (referred to as "Customs" in the rest of this page), or to those wanting to author customs with a similar style to the official ones.

Note that the OCS is a set of guidelines, not rules. That means you are welcome to ignore any part of it - or all of it - when charting your own custom songs. That said, if you are publishing or sharing multiple customs, and they don't follow the OCS, please consider documenting your preferred charting standard, so that your fellow players and chart authors know what to expect.

Common Terms

Note Types

• Every note in a Band BoomBox chart is assigned a type and a class. A note's type determines which button is used to hit it. The following note types are available:

A	B	X	Y	AnyB
Down	Right	Left	Up	AnyD
LB	RB	AnyT

• Note that the AnyT note type is not typically used in any chart difficulty, but it is nonetheless present in the game.
• In addition to a note type, each note is also assigned a note class. A note's class determines what action (if any) the player should take to hit it. The following note classes are available:
  • Tap - This note is hit by pressing the appropriate button once
  • Hold - This note is hit by holding down the appropriate button, until its corresponding Release note arrives. Note: every Hold note must be followed by a Release note!
  • Release - This note marks the end of a Hold note. It is hit by releasing the appropriate button.

Allowed Notes

The term Allowed Notes refers to which note types are recommended for each difficulty in a chart. Each difficulty (Beginner, Medium, Hard, Expert, Extra) has its own set of allowed note types, which are detailed in the following sections. It is strongly recommended to use only these note types when authoring custom songs, as they have been specifically chosen to provide a smooth difficulty curve that can accommodate a wide range of player skill levels.

By default, the built-in Chart Editor will prevent authors from adding note types into chart difficulties that fall outside of the allowed notes list for the current difficulty. However, this behaviour can be disabled by setting the "Allow All Note Types" option to "On" in the Editor Options menu.

Although the OCS defines which notes are valid for each difficulty in Band BoomBox, any note type can nonetheless be used in any difficulty. Although using note types outside the allowed note list for the chart's difficulty is not recommended, doing so will not cause issues during gameplay.

Transfers

A Transfer is defined as any part of a chart where one Hold note begins at the same time as another one ends, like this:

Hitting a Transfer accurately is tricky, especially for less experienced players. For that reason, they should be used sparingly on lower difficulties (see the difficulty sections below for details).

Note that a Tap note at the end of a Hold note is not considered a Transfer. It can still be tricky for less experienced players to hit patterns like these, but they are generally slightly easier than Transfers.

One Button Tapping

One Button Tapping refers to a note sequence that involves hitting the exact same input multiple times:

One Button Tapping is particularly effective on Beginner and Medium difficulties due to the small number of note types available in those difficulties. Consider using patterns such as these to provide some variety to your Beginner and Medium charts:

For higher difficulties, One Button Tapping works well and is recommended in cases where a song repeats the same musical note or percussion sound multiple times:

A good guideline is to have no more than four identical notes in a row. After the fourth note, switch to a different lane, regardless of how many times the same musical note is repeated:

One Hand Tapping

One Hand Tapping refers to a note sequence that involves hitting multiple consecutive notes on the same lane. Unlike One Button Tapping, these patterns are much more difficult for players to hit than notes on alternating lanes, especially on a controller, so such sequences are not recommended:

To avoid One Hand Tapping, the above note sequence should alternate between using using both lanes instead, like this:

This guideline generally applies to all difficulties. However, there are several exceptions, including:

• When the exact same note is repeated multiple times (One Button Tapping):

• When one of the lanes is busy holding down a Hold note (especially on Medium and Hard difficulties). However, there should be fewer notes than usual in this pattern to compensate for the One Hand Tapping:

• On Expert difficulty, the above pattern should instead avoid One Hand Tapping by having a Hold note on one lane, then alternating between the other two available lanes.

• When there is a large gap between two different notes on the same lane.

• Double notes (notes on two lanes at the same time) inevitably involve One Hand Tapping with the notes just before and after them, which is acceptable. However, consider using One Button Tapping in such cases instead to make them easier to hit, especially on lower difficulties.

• On Expert difficulty, alternating between LB and RB notes is acceptable, since these notes are not played with the same hand:

Sections

Any chart that follows the OCS must include proper sections. These are used to partition the song into distinct regions, the boundaries of which are shown on the note highway like this:

[Image]

Prior to v1.5.3, sections did not have any significant impact on gameplay, other than displaying the current section name in the bottom left corner of the screen during gameplay, but they were still useful during the charting process. However, newer versions of Band BoomBox (v1.5.3 and later) introduced section bonuses, which require properly defined sections in the chart to function properly.

Chart sections can be added or changed on the Song Charts screen in the Editor:

Each section consists of a beat number, and a name. The beat number indicates where in the song chart the section begins, with the first playable beat being beat 0. Each section must have a unique name. While sections can be named however you like, officially charted songs generally use the following keywords:

• Intro
• Outro
• Verse
• Chorus
• Prechorus
• Drop
• Bridge
• Break

In addition, the following guidelines are recommended:

• The definitions of the above names aren't set in stone, so feel free to use them as you see fit when designating sections in your chart. Outside of Band BoomBox, terms such as Verse, Chorus, typically refer to songs that have lyrics, but these can be used in Band BoomBox charts regardless of whether they have lyrics or not.
• The same keyword can be used multiple times. In such cases, add a sequence number to the end of the name to keep them unique. For example: "Verse 1", "Verse 2", "Verse 3".
• Even if a section keyword is only used once, it should still end in a number. For example: "Bridge 1", instead of just "Bridge". Intro and Outro are exceptions to this rule.
• Sections can be of any length, but having a new section every 32 beats is generally a good guideline for songs of average BPM.
  • If a song's section continues for much longer than the above guideline (for example, a Verse with 64 beats), consider splitting it into two or more sub-sections. Subsections are indicated with a letter at the end of the section's name. For example: "Verse 1a", "Verse 1b", "Verse 1c"
  • Shorter sections are perfectly fine, especially for small Break sections.

Note that a section that doesn't contain at least 8 notes is not eligible for a Section Bonus. These will be shown as N/A in the Results screen.

Recommended Difficulty Ratings

The following table lists the recommended difficulty ratings for charts. This rating is primarily based on the chart's difficulty (Medium, Mild, Hard etc), and its average NPS (Notes Per Second), as displayed in-game and in the Chart Editor. For Extra charts, use whichever difficulty has the same number of buttons that the chart uses.

Difficulty	Rating	Min NPS	Max NPS
Beginner	1	0.01	1.20
	2	1.20	1.80
	3	1.81	2.50
Medium	2	1.00	1.30
	3	1.30	1.55
	4	1.56	1.90
	5	1.91	2.30
	6	2.31	3.00
Mild	4	1.30	1.80
	5	1.81	2.30
	6	2.31	2.60
	7	2.61	3.00
	8	3.01	3.50
Hard	6	1.60	2.00
	7	2.00	2.60
	8	2.60	2.90
	9	2.91	3.30
	10	3.31	3.70
	11	3.70	4.50
	12	4.51	5.10
	13	5.11	5.70
Expert	10	2.01	2.50
	11	2.51	3.10
	12	3.11	3.70
	13	3.71	4.20
	14	4.21	5.00
	15	5.01	5.50
	16	5.51	6.20
	17	6.21	6.90

Guidelines per Difficulty

Beginner

• Beginner difficulty uses only two note types: AnyD (Any Direction, on the middle lane) and AnyB (Any Button, on the bottom lane). Do not use any other note types on this difficulty. Likewise, avoid using the AnyD and AnyB note types on any difficulty other than Beginner.

• Avoid Transfers, even if they would accurately follow the song's melody. Instead, consider shortening the affected Hold notes, or converting them to Tap notes.
• Avoid having to hit two notes at the same time.
• When creating Beginner charts, remember that they should be very easy. Beginner charts are intended for players with no prior experience with rhythm games. If in doubt, rather make a Beginner chart too easy instead of too difficult.
• Note density: Beginner charts should typically have one note per two beats on songs with an average BPM, with the occasional small chain of notes on every beat. Avoid placing notes that are not on beat, unless absolutely necessary.

Medium

• Medium difficulty uses four note types: Left, Down, A and B. Do not use any other note types on this difficulty.

• Transfers are allowed, but they should be used sparingly, with plenty of gap on either side to allow players to focus on hitting them.

• Even though four note types are available, avoid using all four note types in a row. For example, the sequence below should be simplified like this: Original (avoid) Simplified (recommended)

• Two notes at the same time are acceptable, as long as they avoid excessive One Hand Tapping. When having multiple double notes in a row, these should consist of simple, easy to hit sequences.

• Note density: Medium charts should typically have one note per beat on songs with an average BPM, with the occasional break. A good rule of thumb is to have one break after a chain of seven notes.

Mild

• Mild difficulty uses six note types: Left, Down, Right, A, B, and X. Do not use any other note types on this difficulty.

• Transfers are allowed, with less gap needed on either side of them.

• Unlike with Medium charts, try to use all six button types regularly.

• Two notes at the same time are acceptable, as long as they avoid excessive One Hand Tapping. When having multiple double notes in a row, these should consist of simple, easy to hit sequences.

• Note density: Mild charts should mostly have one note per beat on songs with an average BPM. They should have 1/2 beat note patterns as well, but these should be rare, and consist of easy to hit patterns, like this:

• A sequence of 1/2 beat notes should have at most three notes. If a pattern has more, simplify it as follows: (Avoid) (Good)

Hard

• Hard difficulty uses eight note types: Left, Down, Up, Right, A, B, X and Y. Do not place any notes on the top lane on this difficulty.

• Transfers are allowed, as are more complicated patterns directly before or after them.

• Two notes at the same time are acceptable, as long as they avoid excessive One Hand Tapping. When having multiple double notes in a row, these can use more complicated sequences than Medium charts.

• Note density: Hard charts should typically have small chains of 1/2 beat notes on songs with an average BPM. A good rule of thumb is to split chains with 7 or more 1/2 beat notes into two. Occasional 1/3 beat notes are allowed as well if they follow the song's rhythm, but these should be used sparingly.

Expert

• Expert difficulty uses ten note types: Left, Down, Up, Right, A, B, X, Y, LB and RB. Expert charts should use all three lanes.

• All three lanes should have roughly equal number of notes. Avoid cases where one lane is rarely used (usually the top lane, when converting from Hard charts).

• For the purposes of avoiding One Hand Tapping, the top lane is considered a third "hand". Therefore, none of these patterns are considered One Hand Tapping, regardless of which hand is actually used to hit them:

• Although all three lanes are in use, three notes at the same time are not allowed.

• This rule also applies to Transfers. Avoid having two Holds and a Release note at the same time (or similar).
• All three lanes can be used at the same time, as long as the notes are staggered. For example, these patterns are OK:

• Three Release notes at the same time are also OK, provided that the Hold notes don't start at the same time.

Extra

• The Extra difficulty, as the name implies, is extra space for chart authors to do anything they like. There is only one rule for Extra charts:
  • Anything goes.
• There are no restrictions on the patterns or note types that can be used in an Extra chart.
• Possible uses for the Extra difficulty include:
  • Charts that have a difficulty in between two other difficulties (for example, between Medium and Hard)
  • Charts that are even more difficult than the Expert chart
  • Experimental charts that brazenly defy the OCS or any common sense