• AI means, "All Immediate," and requires that all activations are hit at the first opportunity possible.

• BOD means activate right before the next overdrive phrase (BBM in The Beatles: Rock Band, stands for Before BeatleMania)

• BOD means activate before the next overdrive phrase (BBM in The Beatles: Rock Band, stands for Before BeatleMania)

• BOD means activate before overdrive (BBM in The Beatles: Rock Band, stands for Before BeatleMania)

Notation 1 (GH1 thru GHA)

Notation 2 (Rock Band, Guitar Hero WT - present)

Notation 1 (Rock Band)

Notation 2 (Guitar Hero)

• Noted with the form #(+X)-Y
• The # denotes how many star power phrases must be picked up before the activation.
• The +X denotes how many star power phrases will be gained during the activation.
• The description of when to activate may appear in full text form (as above) or in an abbreviated form, with R, Y, B, O, G, P corresponding to red, yellow, blue, orange, green, and bass respectively.
• NN denotes that one should deploy star power on the next note immediately after gaining the proper amount of star power.
• An example of a star power path is 2(+1)-YBP.
• In the above example, one would deploy star power on the first yellow blue bass note after gaining two star power phrases, and one would gain one star power phrase while under star power.

Credit for this information goes to llamaman2.

Notation 1 (Rock Band)

• BOD means activate before overdrive (BMM in The Beatles: Rock Band, stands for Before BeatleMania)
• PT means Post Talkies in The Beatles: Rock Band
• 2/! warns of a quick, short activation window immediately after gaining the 2nd overdrive phrase

Notation 1

Basic text notation is a series of dash-delimited numbers (e.g., 2-3-2-1). Each number represents how many star power phrases to acquire before activating. These numbers can be augmented with some additional information:

• If there is a prefix 'C' (e.g., C2), it means the activation is 'compressed'. This means one of two things - either that one needs to hold off on whammying hold notes to their full value, or that one needs to activate immediately after acquiring the number of star power phrases designated.
• If there is a prefix 'S' (e.g. S1), it means that the previous activation 'skips' over a number of phrases.
• If there is a prefix 'ES' (e.g. ES1), it means the phrase is 'extra star power'. This star power phrase goes unused by the end of the song.

Some players postfix the numbers with a specific activation point. This is typically either "NN" (meaning next note - the note after the last phrase) or another number and the letters representing the note, meaning that you activate on the Nth version of that note. For example, (3Y) means you activate on the 3rd lone yellow note after the last phrase.
Text notation has difficulty displaying some of the more complex paths (such as purposely activating after a note but not squeezing, or when to activate within a hold).
Credit for this information goes to rkcr.

Notation 2

• Paths without the "when to activate" (i.e. "-Y") portions often separate activations by dashes, and otherwise by commas.

• Paths without the "when to activate" portions often separate activations by dashes, and otherwise by commas.

Note: "Overdrive" and "Star Power" are interchangeable terms in the context below.

• Note: for games where Star Power overlaps and cannot be gained during an activation (i.e. early GH series games), the notation above simplifies to: #-Y

• Bass and guitar paths are noted with the form #(+X)-Y
• The # denotes how many Overdrive phrases must be picked up before the activation.
• The +X denotes how many Overdrive phrases will be gained during the activation.
• The Y denotes when to activate.
• The description of when to activate may appear in full text form (as above) or in an abbreviated form, with G, R, Y, B, and O corresponding to green, red, yellow, blue, and orange, respectively.
• 2G would denote the second green.
• NN denotes that one should deploy overdrive on the next note immediately after gaining the proper amount of Overdrive.
• An example of a guitar overdrive path is 2(+1)-2nd green.
• In the above example, one would deploy Overdrive on the second Green after gaining two overdrive phrases.

Credit for this information goes to MephistoJak.

Bass and Guitar

Drums

• The most basic form of a drum path is #-#-#-#.
• Each # refers to the amount of fills to skip before an activation.
• 0-0-0-0 would require that you activate on the first fill every time.
• 2-0-0-0 would require that you skip two fills, activating on the third fill.
• When drum paths describe squeezing, they feature the #/XY.
• The # refers to the amount of Overdrive fills to skip before activating (e.g. 3/XY would mean to skip three overdrive fills before activating).
• The XY in the notation refers to the notes to hit in the squeeze.
• R for red, Y for yellow, B for blue, G for green, and O for the bass pedal
• Some songs will have a path with a letter "E" for one (or more) of the activations. This means you should hit the last note of the overdrive phrase as early as possible (within the timing window of course). If you do this right you will get a fill to activate right away. The most famous example of this is on Enter Sandman from Rock Band 1. By definition any activations with "E" is going to have no skipping.
• Some songs will have a path with a letter "L" or the phrase "SqOut" for one (or more) of the activations. This means you should hit the last note of the overdrive phrase as late as possible. This is sometimes done to prevent an early fill which you would have to skip and lose points.
• Lastly, sometimes the fill itself must be activated as early or late as possible, to prevent or encourage you to overlap it with another phrase. This is often indicated with a path in text format.

Credit for this information goes to Sully.