iPather at the simplest level is a web-based tool designed to aid gamers in achieving higher scores for the popular Rock Band series of video games.
About Rock Band
In order to understand what iPather does, we must first understand the games upon which its existence is predicated.
The basic idea behind Rock Band, and most other games in the rhythm/music genre, is to simulate playing songs by using musical instrument-shaped game controllers. Generally these instrument controllers include guitar and bass (which utilize the same controller since the instruments they are simulating are more or less the same), and drums. Singing is also possible with any USB microphone and the most recent version of Rock Band supports a keyboard style controller. Rock Band 3 also introduced a "pro" version of the instruments, but that is beyond the scope of this page.
The guitar/bass controller has five color-coded fret buttons that roughly correspond to the first five fret positions on a real guitar or bass. As a simplification of the real instrument, there are not separate buttons for each fret of each string.
A long rocker bar style switch (strum bar) is used to represent strumming up or down on strings. Strumming the bar while holding down a fret button represents pressing on a given fret and strumming the string in order to play a note on the real instrument.
The drum controller is essentially a bare-bones electronic drum set with color-coded pads that correspond to different drums or cymbals. Generally the red pad represents the snare drum, yellow cymbal the hi-hat, blue cymbal a ride cymbal, green cymbal a crash cymbal, and the yellow, blue, and green pads toms. There is also one pedal for the kick drum. As a simplification of the real instrument, there is no hi-hat pedal. Playing the drums in the game is arguably much more like playing real drums in comparison to playing the guitar in game relative to a real guitar.
The keyboard controller is basically a real, electronic keyboard but with fewer keys to make it smaller and more manageable. During normal (non-pro) gameplay, the C, D, E, F, and G keys are used in the same fashion as the five fret buttons of the guitar controller. As a simplification of the real instrument, the keys on the keyboard do not necessarily correspond to the actual musical pitches played in the real song. They do during the pro mode of gameplay however.
No special controller is required for the vocal gameplay mode. Any standard USB microphone can be used to allow the player to sing and try to match the correct pitches.
Each instrument, except vocals, is represented on screen by a note highway, which resembles a guitar neck going up the screen off into the distance. The horizontal lines on the highway that look like frets of a guitar assist the player because they represent the beat of the song. The thicker lines correspond to beats and the thinner lines to off beats. Each highway has lanes corresponding to different color notes: green, red, yellow, blue, and orange. Each note is represented by a gem within its respective lane. During gameplay, the gems appear to come toward the player in sync with the music of the particular song the player has chosen. When gems line up with the strike bar toward the bottom of the note highway, the player must play the given note or notes to score points.
Five lanes appear when playing guitar (pictured above, left) or bass (above, right). When the note or notes align with the strike bar the player must strum the strum bar with the correct fret buttons held down. This is generally accomplished by pressing and holding the correct button(s) in advance and then strumming at the appropriate moment, similarly to how one would play a real guitar or bass.
Five lanes also appear for the normal (non-pro) keyboard (not pictured but appears the same as the guitar part). In the keyboard's case however, the green, red, yellow, blue, and orange notes correspond to any C, D, E, F, and G keys respectively on the keyboard controller. Simply pressing down on a key plays the note at that instant, just as with a real keyboard.
Drums only have four lanes (red, yellow, blue, and green, pictured in center), which correspond to the color-coded pads and cymbals on the drum controller. Instead of the fifth orange lane, an orange note corresponds to the kick pedal and is represented by an orange bar that stretches the width of the note highway underneath the regular gems. Unsurprisingly, hitting a pad or cymbal with a drum stick or stepping on the kick pedal plays the corresponding note. In the case where a particular color note has both a pad and cymbal of the same color, hitting either counts in the normal (non-pro) mode. For example, hitting either the green cymbal or the green pad counts when a green note appears on screen.
The main goal of playing Rock Band (aside from having fun) is to score the maximum number of points possible. This is achieved by playing the correct notes at the correct time. The more notes the player hits, the more points they earn.
For all non-pro instruments except vocals, each gem has a base score of 25 points. For chords (when multiple gems appear at the exact same moment), the base score earned is 25 times the number of gems in the chord. For guitar, bass, and keyboard, some notes are sustained (pictured below on the left and right). These notes can be worth an additional 12 base points per musical beat of their duration, which are earned when the player keeps the correct button held down. If they keep the button held down for the entire duration, they earn the maximum amount, otherwise they earn a percentage based on how long they held the correct button down.
When a player plays consecutive notes correctly, their note streak is incremented, which the game rewards by increasing the player's score multiplier. For every 10 notes in a row the player hits correctly, their multiplier increases by one, with a maximum of 4x for every instrument except bass, which has a maximum of 6x. If the player misses a note, or plays a note that isn't there (overstrum or overhit), the multiplier is reset to 1x. When a player hits a note or chord, the actual number of points added to the score is the above base score multiplied by the current multiplier. For example, a single gem hit correctly when the multiplier is 4x is actually worth 100 points. The current multiplier is displayed to the right of the circle in the bottom middle of the note highway when it is greater than 1x. The aforementioned circle indicates progress toward increasing the multiplier in a pie graph style.
Another mechanic that keeps the game interesting and has the largest impact on the score, aside from hitting the notes in the first place, is called overdrive. The player earns overdrive by hitting specially designated overdrive phrases, which appear as a series of white gems (pictured below). The amount of overdrive the player currently has is indicated with the horizontal bar at the bottom of the note highway, below the strike bar. In the below picture, the overdrive meter is a bit less than one quarter full. When the overdrive meter is at least half full, the player can activate the overdrive. While the overdrive lasts, the score multiplier will be doubled compared to what it would normally be. The general idea is to activate overdrive during note-dense sections of the song while not making any mistakes so that the player has an 8x multiplier and is therefore earning 200 points per gem. If the overdrive meter is full, no additional overdrive may be earned even if the player hits an overdrive phrase successfully. Therefore it is usually not desirable to hoard overdrive (collecting overdrive without using it). Furthermore, overdrive can continue to be earned should overdrive be active and the player hits another overdrive phrase. In this case, the current overdrive activation's duration is extended.
To activate overdrive, guitar and bass players can simply hold their guitar vertically, like a rock star, or press the designated controller button to activate. Keyboard players also have a designated button. For drums, the player must hit the green pad or cymbal at the end of specially designated drum fill sections (pictured below) that appear once the player has accumulated enough overdrive. When these fill sections appear, they "cover up" any notes that would normally be there. The player may play any notes during these sections without penalty, but no points are awarded. Therefore, the drummer must consider the cost of waiting to activate in order to accumulate more overdrive for a longer, later activation compared to the missed points while the fill sections are active.
Once activated, overdrive lasts for a certain number of beats depending on how full the overdrive bar is. If the bar is full, overdrive will last for 32 beats. Half full will last 16 beats. Should the player hit another overdrive phrase while overdrive is active, the overdrive will remain active for an additional 8 beats (in the simplest case).
When playing with more than one player, use of overdrive increases everyone's multiplier by 2x, 4x, 6x, and 8x when one, two, three, or four players respectively have their individual overdrives activated. In the full band picture up the page, all four players have activated their overdrive making for an 8x overall multiplier, displayed to the left of the score. An 8x overall multiplier combined with an individual player's 4x multiplier makes each gem worth 800 points. This means that one must consider simultaneous overdrive activation to obtain more points when playing with other people.
Sometimes multiple instruments have simultaneous overdrive phrases. In these cases, each instrument receives an additional quarter bar of overdrive if all of the instruments hit their respective phrases (unison bonus). In Rock Band 3, the player will receive the bonus overdrive automatically if they are playing by themselves. In the earlier games, it was not possible to earn the bonus when there was only one player, therefore the player tends to get more overdrive when playing a song in Rock Band 3 compared to playing the same song in an earlier game, which can affect the optimal use of overdrive. Note that the vocal part never contributes to or benefits from unison bonuses.
During an overdrive phrase in which sustain notes are present, guitar and bass players can press up and down on the controller's whammy bar during the sustain notes to gain a little extra overdrive, depending on how long the sustain notes are and how well they whammy. The keyboard player also benefits from this game mechanic, but the keyboard controller has a touch-sensitive strip the player slides their finger back and forth on instead of an actual whammy bar. This allows players to gain more than a quarter bar of overdrive from a single overdrive phrase and in some instances enough to activate without hitting a second overdrive phrase.
Drums cannot whammy as they never have sustain notes.
Guitar solos are fundamental to many rock songs. Rock Band emphasizes this by designating solo sections with a blue background and rewards the player at the end of the solo with bonus points depending how well they hit the notes in the section. Drums and keyboard parts can also have solos. This video illustrates an unusually long guitar solo. Notice at the end of the solo, the player hit 100% of the notes as indicated by the "perfect solo" notice and received an additional 50,000 points. Note that in this example the end of the solo section immediately goes into a big rock ending, discussed below.
Big Rock Endings
The ending of some songs isn't always clear cut, often with the band jamming out for a few seconds. Instead of trying to convert these types of endings into a sequence of notes like the rest of the song, the creators of the game decided to turn them into free form sections where the player can play whatever they want. Points are earned every time any note is played but fewer points are earned if the same note is repeated too quickly. After the free form section, there are a handful of final notes that the player must hit in order to actually receive the bonus points. These special final notes do not award the standard 25 base points. They simply determine whether or not the player gets the bonus points. The above video features the end of a guitar solo transitioning immediately to a big rock ending.
The vocal part has some distinctions compared to other instruments. Instead of a vertical note highway, vocals have a horizontal band in which lyrics and lines representing the pitches to sing scroll. On the left side of this bar is an arrow that indicates the current pitch the player is singing into the microphone. If the arrow lines up with the current pitch line underneath it then the player is correctly singing the part. The player can sing in any octave so long as the pitch is correct.
Another important distinction is that the vocal part is split into many phrases for scoring purposes, indicated by vertical bars. Each phrase is worth a base score of 1000, 800, 400, or 200 points when playing on the expert, hard, medium, or easy difficulty respectively. In order to score the maximum number of points, the player must sing a certain percentage of notes correctly within a phrase. The harder the difficulty the less forgiving the game engine is in determining how well the player sings. As the player sings a phrase, the circular pie chart just below the lyrics fills up to indicate they are singing well. If it fills up completely, the player will get an "awesome" rating for that phrase and receive the full amount of possible points as well as increase their score multiplier, up to a maximum of 4x. If instead it is partially filled, the player will receive a relative percentage of the base points and the multiplier reset to 1x. The other phrase ratings are "strong," "okay," "weak," and "messy." It is possible to fill the pie chart without necessarily being completely perfect or singing every single note of a given phrase in order to give the game a certain margin of error so that it is not frustratingly difficult.
Vocal overdrive phrases are indicated by pitch lines that glow yellow/gold (seen below, center). The player must receive an awesome rating in order to get the overdrive. Once the overdrive meter is at least half full, activation windows will appear (seen below, left and right) where there are large enough gaps between notes where the vocalist can make a loud noise (such as Wooooooooooo! or screaming), or press the designated button on the controller (if they are feeling less flamboyant), in order to activate the overdrive.
Vocals do not participate in big rock endings
While there are not vocal solos in the same sense as there are for guitar or drums, some songs feature percussion or tap sections that mimic when the vocalist might clap or play a tambourine or cowbell. In order to hit the notes, the player taps the microphone, or presses the designated button on the controller. As with the other instrument solos, the player receives bonus points depending on how many of the notes they hit. Unlike the other instruments however, hitting the vocal percussion notes are completely optional, though most players will want to hit them for the additional points. A percussion section can be seen in this video.
"iPather" is short for "Interactive Rock Band Pather." Its name refers to the process of pathing, which is the art of determining where to activate overdrive to achieve the most points. This results in a path, which is simply a description of the exact moments for a player to activate overdrive. iPather allows its users to study the songs that appear within Rock Band "offline," which is to say without having to actually play the game. The main advantage of this is that the player can only examine the songs in real time when playing the game or at a slower speed when utilizing the game's practice mode. If the player wishes to review a specific section, they must constantly replay other parts of the song that are irrelevant to what they are currently studying.
The static representations of Rock Band songs that iPather provides are called note charts, which are simply PNG images. Below is a snippet of a guitar chart that corresponds to the first few seconds of this video. You will notice the running score of the fourth measure in the image exactly matches the score shown in the video after the second red+yellow note.
The main features of the charts are:
- the staff that contains the notes. This somewhat resembles a traditional musical staff. The current tempo is listed above the staff in beats per minute as well as measure numbers. In addition to bar lines, the chart displays beat lines and half-beat lines to make it clear where notes lie within the measure. Also, the time signature is displayed as needed when it changes.
- the notes themselves. Instead of traditional note shapes, the notes are rectangular as a simple approximation of the way they appear in-game. Also, instead of different stems or dots and ties that indicate length, notes simply have a tail that shows their exact duration, if they are hold notes. Again, this mimics how the notes are portrayed in-game.
- base score per measure. On the bottom right of each measure in black is the sum of all the points available within the measure, assuming a 1x multiplier. This helps to see where the more point-heavy sections of the song are, which is important in determining where to activate overdrive.
- running score. Below the base score in red is the cumulative score to the end of the measure, which accounts for changes in the score multiplier. This number is what the player can usually expect to see as their score in-game at that point. By manipulating the overdrive activations (discussed later) this number will change to reflect the current score. The general idea is to make this number as high as possible by the end of the song. This does not include bonus points that are obtained.
- running score with bonus points. Where applicable, iPather displays the running score with the addition of any bonus points that might be obtained from solo or big rock ending sections in green to the left of the running score without bonus points. If this score is displayed on the chart, the player can expect to see this number in-game instead of the running score described above. The reason for providing this number is that the bonus points are incidental with regard to overdrive activation and do not need to be considered by the player, but it is necessary to include them in order to properly compare a chart iPather provides with a score obtained while actually playing the game.
- section names. Each song within Rock Band is broken into several named sections to make it easier to practice a small portion of the song without having to play the entire song. iPather displays the start of each section as a reference point to make it easier to find a specific area the user is interested in. In the above image, the "intro" section happens to overlap the first note where the 1x multiplier is indicated.
overdrive phrase indicators. Since knowing where overdrive phrases occur within a chart is critical in figuring
out where to later use the overdrive, iPather indicates them by drawing the notes that comprise the phrase
gray (instead of their normal green, red, yellow, blue, or orange color), which corresponds to their distinct
in-game appearance, on a green background, as pictured below.
- whammy indicators. The extra overdrive obtainable via whammying is based on the duration of the sustain notes in the overdrive phrase. For every beat the player can whammy, they earn approximately 1.1 beats worth of overdrive, keeping in mind the overdrive phrase itself is worth eight beats (i.e. one quarter of the overdrive meter). The total number of whammyable beats in a measure are displayed in blue below the running score. In the above example, there are two sustain notes that are each half a beat in length, for a total of one whammyable beat in the measure. When there is a sustained chord, the length only counts once, as seen farther down this page.
drum fill indicators. Once a drummer has at least half a bar of overdrive, the places where drum fills can
appear are predefined in the raw chart data. iPather denotes these with a light red and white striped background.
In measures where drum fills can potentially appear, the number of base points that can be obtained should
the fill be active and covering notes is displayed to the left of the measure's base score in red. Displayed
under the start of a drum fill in blue is the number of seconds that have elapsed since the last overdrive note.
This is critical because the game engine will not mark a drum fill as active until a certain amount of time from
when the player has obtained half a bar of overdrive has elapsed. The exact time of this varies depending on
which game is being played and certain settings within the game. Notice in the below example that 50 points
are deducted from measure 15's base score because the first yellow+orange note in that measure coincides with
the end of the drum fill section. In-game, this yellow+orange note is actually replaced with a special green note
that does not award points but rather activates overdrive should the player hit it.
solo indicators. Notes that lie within a solo section have a blue background that corresponds to how they are
denoted in-game. At the end of the solo section, the number of bonus points awarded is displayed above the staff.
big rock ending indicators. Big rock ending sections are indicated with a light red background where they
occur. iPather displays notes within these sections even though they do not appear in-game (though they
are used by the game for animation purposes) simply because they are in the raw chart data. You will notice
that notes within and after a big rock ending do not give any additional points. iPather provides a rough
estimate of the obtainable points in a big rock ending based on its duration, but it is virtually
impossible to obtain an exact number of points when playing in-game.
Generating these note charts is not a new idea. Charts for the earlier Rock Band games have been provided by Andy Janata (ajanata) in the past. While all of iPather's code has been created by me, I made a point to duplicate the visual style and score calculation results of Andy's charts as a starting point for my work. This is mainly because his charts are accurate and have become so widely used that those already familiar with his format would easily understand mine, not to mention that he did a nice job in the first place.
If iPather only provided the same features as Andy's charts then there would not have been much point in creating it. Some of the additions include:
- multiplier changes. Whenever the score multiplier changes based on the current note streak the chart indicates it above the staff.
unison bonus indicators. While it is usually obvious when there would be a unison bonus when looking
at a chart with multiple parts, there is no indication when looking at a solo instrument chart. One
would need to reference a multi-part chart and go back and forth between the two. Also, there can
be certain times where there is no unison bonus when it appears there could be. iPather checks the
raw chart data to make this determination and indicates it with yellow edges around the green overdrive
phrase indicator, as pictured below.
- charts for keyboard parts. Rock Band 3 introduced the keyboard controller as a new gameplay option, which Andy's charts do not support. There are certain technical differences the keyboard part brought to the table that posed an additional challenge over the other instruments.
- calculation of vocal points. While optimal overdrive usage does not change with vocals across difficulties like it does with the other instruments (vocal notes remain the same, the game simply is more lenient and awards fewer points on the lower difficulties), calculating the vocal points earned is important in calculating the score earned by the band as a whole so that they can see how close they came to the projected score when they actually play the game.
overdrive activation indicators. When a user specifies where to activate overdrive, iPather draws that section
with a yellow background and automatically calculates the score accounting for the multiplier changes. iPather
also draws the overall multiplier changes above the staff that result from overdrive being active.
- dynamic score calculation. This is iPather's single most significant feature, which is discussed in greater detail below.
Dynamic Score Calculation
iPather's main selling point that sets it apart is its ability to let users specify where they want to activate overdrive and to adjust the activation's exact position and duration on the fly with an innovative web-based interface. iPather recalculates the score whenever the user makes an adjustment so that they can see immediately how a minor tweak will affect it. Under the hood, iPather takes care of all the little details that come into play when calculating the score.