Bytebeat is a [procedural](procgen.md) [chiptune](chiptune.md)/8bit style [music](music.md) generated by a short expression in a [programming language](programming_language.md); it was discovered/highlighted in 2011 by [Viznut](viznut.md) (author of [countercomplex](countercomplex.md) blog) and others, and the technique capable of producing quite impressive music by single-line code has since caught the attention of many programmers, especially in [demoscene](demoscene.md). There has even been a [paper](https://arxiv.org/abs/1112.1368) written about bytebeat. Bytebeat can produce music similar (though a lot simpler) to that created e.g. with [music trackers](music_tracker.md) but with a lot less complexity and effort. These techniques can also be used to produce non-musical sounds, one may imagine for example imagine a racing game where the sound of car engine is created this way.
This is a [beautiful](beauty.md) [hack](hacking.md) for [LRS](lrs.md)/[suckless](suckless.md) programmers because it takes quite a tiny amount of code, space and effort to produce nice music, e.g. for [games](game.md) (done e.g. by [Anarch](anarch.md)).
8bit samples corresponding to `unsigned char` are typically used with bytebeat. The formulas take advantage of [overflows](overflow.md) that create rhythmical patterns with potential other operations such as multiplication, division, addition, squaring, bitwise/logical operators and conditions adding more interesting effects.
Quick experiments with bytebeat can be performed with online tools that are easy to find on the [web](www.md), these usually use [JavaScript](javascript.md).
Nevertheless, traditionally we use [C](c.md) for bytebeat. We simply create a loop with a *time* variable (`i`) and inside the loop body we create our bytebeat expression with the variable to compute a char that we output.
A simple "workflow" for bytebeat "development" can be set up as follows. Firstly write a C program:
```
#include <stdio.h>
int main(void)
{
for (int i = 0; i <10000;++i)
putchar(
i / 3 // <bytebeatformulahere
);
return 0;
}
```
Now compile the program and play its output e.g. like this:
```
gcc program.c && ./a.out | aplay
```
Now we can just start experimenting and invent new music by fiddling with the formula indicated by the comment.
General tips/tricks and observations are these:
- Outputting the variable `i` creates a periodical saw-shaped beat, **multiplication/division decreases/increases the speed, addition/subtraction shifts the phase backward/forward**.
- Squaring (and other powers) create a **wah-wah effect**.
- Crazier patterns can be achieved by **using the variable in places of numerical constants**, e.g. `i << ((i / 512) % 8)` (shifting by a value that depends on the variable).
- Modulo (`%`) increases the frequency and **decreases volume** (limits the wave peak).
- So called **Sierpinski harmonies** are often used melodic expressions of the form `i*N & i >> M`.
- Bitwise and (`&`) can add distortion (create steps in the wave).
- A **macro structure** of the song (silent/louds parts, verse/chorus, ...) can be achieved by combining multiple patterns with some low-frequency pattern, e.g. this alternates a slower and faster beat: `int cond = (i & 0x8000) == 0;`, `cond * (i / 16) + !cond * (i / 32)`
- **Extra variables** can add more complexity (e.g. precompute some variable `a` which will subsequently be used multiple times in the final formula).
It is not exactly clear whether, how and to what extent [copyright](copyright.md) can apply to bytebeat: on one hand we have a short formula that's uncopyrightable (just like mathematical formulas), on the other hand we have music, an artistic expression. Many authors of bytebeat "release" their creations under [free](free_culture.md) [licenses](license.md) such as [CC-BY-SA](cc-by-sa.md), but such licenses are of course not applicable if copyright can't even arise.
The following more complex examples come from the [LRS](lrs.md) game [Anarch](anarch.md) (these are legally safe even in case copyright can apply to bytebeat as Anarch is released under [CC0](cc0.md)):
