Introduction
Kroytz's Guide to Stream Mapping

Whether you're looking to create a short and simple stream or a long gruesome deathstream, this guide has it all. In this discussion, we'll look over and analyze a variety of different songs and stream designs and what you should be looking out for when mapping them!

Chapters

1. Free-hand vs. Slider-to-stream
2. Accentuating Strong Beats
3. Variety
4. Kick-slider Streams
5. Streams as a Form of Expression
6. Example Stream Designs

Free-hand vs. Slider-to-stream

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In this age old question we ask ourselves, "Which is better: making streams by hand or slider-to-stream conversion?" and the answer is quite simple if we organize the question in a slightly different manner. Let me ask you, would you rather draw a perfect circle by hand or with a circle creation tool? Well, if we tried to draw a circle by hand then there's most likely going to be imperfections, so obviously it's better to draw a circle through the use of a tool or program right? However, this is only the case if what you wanted was a perfect circle.
So again let's ask ourselves, which is better: making streams by hand or slider-to-stream conversion? And the answer is dependent on the theme or feel you have or will establish for your map - whether you want to express the map through clean perfect shapes or hard rigid designs is all up to your creative interpretation.

In my opinion, I feel that slider-to-stream conversion will be useful for at least 90% of all stream creations; to make the most smoothest and close-to-perfect looking designs you'll need the assistance and convenience of a tool to do it for you. The last 10% would be for the cases in which the mapper would like to express their map through imperfections as a "thematic" approach to stream mapping. This is highly song dependent and takes a very distinct approach to stream mapping, best saved for experienced mappers who already have an understanding of unique map expressions outside of streams.

Accentuating Strong Beats

In order to accentuate or emphasize the proper beats in a stream, first we have to learn a little bit of music theory:

Measure



Phrase



In a time signature that is 4/4, each measure is comprised of four quarter note beats, or in osu language that is four 1/1's and a total of 16 clickable beats (with red and blue ticks).
Usually, music is based on subdivisions that goes something like this: weak | STRONG | weak | STRONG | for every phrase and for every measure. We can call this an ABAB pattern. It's for this theory that we use claps on 2's and 4's and possibly whistles on 1's and 3's.

However, with streamy songs or music with intense guitar solos, music composition changes a little bit and suddenly looks more like this:

Measure



The main difference between streamy parts of a song and non-streamy parts is that the first half of the measure shares equal importance as the second half. We can call this an AABB pattern and depending on how the song is composed either [ AA ] can be stronger than [ BB ] OR [ BB ] can be stronger than [ AA ].
It is important to listen to the song carefully and find where the dominating sounds are or which part of the measure is stronger.

The phrase will more than likely resemble an ABAB pattern just like non-streamy songs and for either [ A ] or [ B ] you can add some variations to keep the map more interesting. Although, it's not uncommon to see a phrase use an AABB pattern or even an ABCD pattern.

When it comes to continuous 1/4 drumrolls presented in genres such as metal, rock, or hardstyle, these theories may not apply very well. Drums on 1/4's are always equal to each other and therefore present no distinct pattern, it'll simply be AAAA all throughout the measure and sometimes for an entire phrase. If the song presents a secondary instrument such as a violin or vocal, it is possible to use that as an indicator for internal pattern creation and resolve yourself back to AABB or ABAB patterns.

Lastly, some songs like to use arpeggios within their measures. An arpeggio can be defined as a chord of notes played up or down a scale. The type of arpeggio I will refer to use 4 notes in succession and look a bit like this:

[1, 2, 3, 4]
[2, 3, 4, 5]
[3, 4, 5, 6]
[4, 5, 6, 7]

In cases where arpeggios are used, it is possible to emphasize each strong white tick where the first note of each arpeggio begins.

Variety

One of the worst things to come across in a stream map/section is when you see 100% circles, all equally spaced, and it just never ends. Because we know that music works on subdivisions whether it happens within a measure or within a phrase, there is room to utilize various expressions. As a general rule of a thumb - too little variety makes for a bland map, and too much variety makes for a confused map. There needs to be a balance between emphasizing circles/sliders and distance spacing between circles/sliders.

Kick Sliders - By far the easiest way to emphasize streams. You can use repeat sliders right before a spaced stream to bring attention to that stream and use repeat sliders to bring the intensity down. You can have a spaced stream and use high spaced kick sliders to emphasize the sounds for the kick sliders thus making the previous stream a weak stream to the music. Kick sliders are also a way to flow into many more streams because of slider leniency.

Stream Jumps - Usage of streams jumps are highly dependent on music composition and should not be used haphazardly. Common ways to use them are in Arpeggios of 4 or 8, or as two doubles for a stream of 5 circles (also commonly known as Hanzer streams). Other ways of utilizing stream jumps are to separate weak and strong measures.


Low DS Streams vs Spaced Streams - Similar to what's been theorized before, low DS Streams imply a weak part of the song whereas Spaced Streams imply it's stronger. Direct ways to use low DS is when the song is heavy on the bass or in combination with added kick sliders since kick sliders can often times jump to other kick sliders/streams (if they are stronger). Direct ways to use high DS or Spaced Streams is when the song becomes noticeably louder or heavy on trebles.


Accelerating and Decelerating Streams - These streams are often less intuitive to play so please be wary of using them. Their slight awkwardness can help benefit a song's interpretation if it can have a good follow-up or if it acts as a phrase's ending measure. Varying acceleration and deceleration streams within short time parameters is generally unadvised because of how much the player has to adjust to the DS. The difference between accel/decel streams and low/high space streams is that with accel/decel there are multiple DS changes whereas low/high have only two DS changes.

Kick-Slider Streams

Kick slider streams are one of the hardest type of streams to map correctly because of how limited you are in object placement. Unlike normal streams which have varying ways to space and emphasize certain parts of the measure, kick slider streams don't have much of a choice but to be spaced evenly due to how uncomfortable they play in any other arrangement. The real difficulty that comes with kick slider stream is "design creation"; they will generally play as a 1/4 stream, but with the added slider-tail you are able to create nifty little designs that can really spice up your map.

Most kick slider streams are mapped in 1/8 so that each kick slider is treated as a pseudo 1/4 circle. It's not uncommon to see songs use 1/6 sounds where everything else is mostly 1/4s. In these rare cases, using 1/6 kick slider streams is also viable albeit slightly more uncomfortable than 1/8 because of snap changes.

Kick slider streams in the midst of a normal 1/4 stream usually don't play comfortably from my experience. Maybe if the song really calls for it, it might be viable? But I would personally advise against this.

Streams as a Form of Expression

It sounds simple to just place circles in continuous 1/4 rhythm and emphasize the strong beats, lower the spacing on weaker beats perhaps, add a kick slider to deviate weaker/stronger parts of the phrase sure - this is all fundamental ways to look at mapping streams. But, the hardest most complex type of stream to map are the "expressive" forms of stream mapping.

They are the most difficult type of stream to map simply because they ignore fundamental mapping theory and focus on an artificial theme created by the mapper. Mapper's interpretation and subjectivity also come in to play here but there are unique ways to establish a theme to compliment the song, and "sub-optimal" ways to establish a theme since there is no right or wrong way to interpret a song. Basically, "my mapping style make objective sense, and not make your sense."
Here are some things to look out for:

Ignore everything you learned about rhythm - That's right. NC's on downbeats? Not needed. Emphasizing the white ticks? Maybe, maybe not. Despite osu being a rhythm game, mapping is also a way to show others your own unique interpretation. One of the most direct ways to do this is to subjugate rhythm and create an array of objects that represent the music in an atypical manner. If there are powerful white ticks, it's possible to showcase the red ticks along with them, be creative!

Ignore everything you learned about spacing - Well, maybe not everything. There should be at least some sort of logic behind the spacing but if what you're mapping has a plethora of ever so changing volumes and keys, then it's not wrong to try and space them accordingly to how they are composed, even if this means that every circle is different. Keep in mind that having too much variety can be confusing so definitely take that into consideration.

Ignore everything you learned about stream design - Designing streams can often be in regular shapes or irregular shapes such as a circular stream blanketing a circle versus an oval stream that does not blanket anything. However, when it comes to expressing music individualistically, it may not be worth trying to make every design typical or clean. Even some irregular stream shapes are kept typical to some degree like proper distant spacing or downbeat emphasis.
With unique expressions, designs don't have to be regular. This is not to say to make them "ugly" but think about the artificial theme you're creating and use streams as a way to enforce that theme. It's possible to utilize odd angles and linear streams in combination with curves for example. If you think to yourself, "does this look typical?" you might want to make it less typical and keep things fresh~

Example Stream Designs

These are some tool-assisted stream designs that are fairly reusable to many songs. They aren't proprietary in any way but they do take a bit of ingenuity to use properly when the time comes for them. Casually tossing designs around don't make for a good stream map, it's more about how you can use designs to transition from one stream to another. Like the name suggests, a stream should feel like an ever flowing river of circles~