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Black MIDI

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Re: Black MIDI

#41

Post by maze-le »

sheepdestroyer wrote: post #30
praptak wrote: post #6

Some (most?) of the black midi scores do cheat a bit. They have bajillions of notes but most of the notes are not audible. Their presence gives cool visual effects (either static if you decide to print it out as classic music notation or dynamic when an app plays the tune) and that's it. Edit: they typically still have enough audible notes to make it sound like a dozen clones of Chopin played together.

Tau ("the Song with 6.28318 Million Notes") is an extreme example : https://www.youtube.com/watch?v=b0gyQMJHQ78 I like the "no arts" version that removes silent notes, as it makes it more enjoyable (for me!) to follow what's happening : https://www.youtube.com/watch?v=VcfmPZVqVtw However, one other interesting aspect of a song like Tau is the "performance" of playing these note-heavy midis. You are effectively record…

Its like watching a 'shoot em up' lets play from the early 90ies...

Re: Black MIDI

#42

Post by lewispollard »

Rochus wrote: post #34
praptak wrote: post #27

Earlier quoted context omitted.

I don't believe black midi can be played on normal instruments, it's mostly computer-based (barring the punchcard pianos). In fact even standard pre-black-midi software would probably crash when trying to open such files.

A piano has only 88 keys (if you play outside of those it doesn't sound like a piano anymore, even on a computer). And if you use more than one piano at the same time, all what happens is a phasing effect if more than one hits the same note at the "same" time.

The point is that if the MIDI file and the synthesiser in question are all on the same system (i.e. a VST in a DAW), no MIDI data transfer has to take place. So the data transfer limit in question isn't applicable.

Re: Black MIDI

#44

Post by mkl »

Rochus wrote: post #38
mkl wrote: post #37

Earlier quoted context omitted.

I think you're misunderstanding. The slow-motion screen recording video can be sped up to match separate non-realtime software synthesis of audio (using e.g. Timidity++). It can all be entirely software so there aren't physical limits to worry about.

Try to do that with a factor of e.g. 10 (you would likely need a factor of 1000 to cope with a "composition" of millions of notes) and observe the quality. The "physical limits" (e.g. Nyquist rate) also apply to the calculations done by a computer. To cope with the speed-up of slow motion to real-time you'd have to re-sample or transpose. Even with a very large sampling rate both of these transformations only produce…

The quality will be essentially perfect. The wave file is rendered in software, as slowly as it needs to go. The rendering speed has nothing to do with playback speed, sampling rate, or frequency. Think of it like a ray tracer generating a few pixels a second and gradually building up the frames of a movie. You could generate one audio sample per second and save them to a file, and twelve hours or so later you'd have a 1-second long piece of 44.1kHz audio. There is no speeding up or resampling or transposition involved because the audio file was generated with the right sample rate (nothing to do with the generation/calculation rate).

Re: Black MIDI

#45

Post by gaudat »

praptak wrote: post #6

Some (most?) of the black midi scores do cheat a bit. They have bajillions of notes but most of the notes are not audible. Their presence gives cool visual effects (either static if you decide to print it out as classic music notation or dynamic when an app plays the tune) and that's it. Edit: they typically still have enough audible notes to make it sound like a dozen clones of Chopin played together.

Back when I was a kid I played with some of those black MIDI files. I think one of the tricks is to put the same melody on multiple octaves. It makes the sound fuller without going dissonant.

There is also a phase like effect that can be done by playing sgales really quickly. I think I saw that in one of the original Touhou black midi files.

And of course there is pressng all 88 keys on the MIDI piano at the same time. I would like to know what that sounds like on a real piano though.

I think black MIDI starts as a rendering artifact in a Japanese music notation software. The name was "Frieve" or something. It renders as many notes put in a measure. Without expanding the view. That is sort of what's going on in the Wikipedia pic.

Re: Black MIDI

#47

Post by bskrobisz »

gaudat wrote: post #45
praptak wrote: post #6

Some (most?) of the black midi scores do cheat a bit. They have bajillions of notes but most of the notes are not audible. Their presence gives cool visual effects (either static if you decide to print it out as classic music notation or dynamic when an app plays the tune) and that's it. Edit: they typically still have enough audible notes to make it sound like a dozen clones of Chopin played together.

Back when I was a kid I played with some of those black MIDI files. I think one of the tricks is to put the same melody on multiple octaves. It makes the sound fuller without going dissonant. There is also a phase like effect that can be done by playing sgales really quickly. I think I saw that in one of the original Touhou black midi files. And of course there is pressng all 88 keys on the MIDI piano at the same tim…

>And of course there is pressng all 88 keys on the MIDI piano at the same time. I would like to know what that sounds like on a real piano though.

The mute pedal on an upright/console piano works by situating the hammers closer to the strings; if you stomp on it hard enough, you can get it to jerk all of the hammers such that they actually hit the strings and get this "all 88 keys" noise. I don't recommend this if you care for the piano, though :)

(On a grand piano, IIRC the mute pedal instead either adjusts the position of the hammer to only hit 1-2 of the strings, instead of all 3, or it moves the felts to dampen the sound).

Re: Black MIDI

#48

Post by Rochus »

mkl wrote: post #44
Rochus wrote: post #38

Earlier quoted context omitted.

Try to do that with a factor of e.g. 10 (you would likely need a factor of 1000 to cope with a "composition" of millions of notes) and observe the quality. The "physical limits" (e.g. Nyquist rate) also apply to the calculations done by a computer. To cope with the speed-up of slow motion to real-time you'd have to re-sample or transpose. Even with a very large sampling rate both of these transformations only produce…

The quality will be essentially perfect. The wave file is rendered in software, as slowly as it needs to go. The rendering speed has nothing to do with playback speed, sampling rate, or frequency. Think of it like a ray tracer generating a few pixels a second and gradually building up the frames of a movie. You could generate one audio sample per second and save them to a file, and twelve hours or so later you'd have…

I responded to the fellow stating "The article says they sometimes play them slowly and speed the recording up to the correct speed afterwards." which implies a change to the time scale. But also if you do a "perfect" non-realtime offline rendering Black MIDI is pointless; a piano has 88 keys; if you want to play thousands of notes a second then the only "benefit" you get is either a comb filter effect when the same note is triggered nearly the same time or a 3 dB gain (on maximum) if triggered exactly at the same time; there are easier ways to achieve this, even in real-time.

Re: Black MIDI

#49

Post by Rochus »

lewispollard wrote: post #42
Rochus wrote: post #34

Earlier quoted context omitted.

A piano has only 88 keys (if you play outside of those it doesn't sound like a piano anymore, even on a computer). And if you use more than one piano at the same time, all what happens is a phasing effect if more than one hits the same note at the "same" time.

The point is that if the MIDI file and the synthesiser in question are all on the same system (i.e. a VST in a DAW), no MIDI data transfer has to take place. So the data transfer limit in question isn't applicable.

Even if it's on the same system your piano still has 88 keys and you get either a loudness gain per key or a phasing effect when a key is played more than once per time. The only somewhat interesting effect (at least for some) might be that the generator hits its limits (usually 20 to 40 notes polyphony) and randomly decides which notes to leave out or prioritize. But this is out of control of the "composer" and likely not the intended effect.

Re: Black MIDI

#50

Post by jacquesm »

praptak wrote: post #27
Rochus wrote: post #24

Earlier quoted context omitted.

> They have bajillions of notes but most of the notes are not audible Good point; and if they would be audible the latency would have been unbearable, since the MIDI 1.x protocol only supports ~31kbit/s; each note requires 3 bytes for on an off each; so e.g. a chord with more than ~20 notes no longer sounds like a chord, but like an arpeggio; many expanders I had were even slower.

I don't believe black midi can be played on normal instruments, it's mostly computer-based (barring the punchcard pianos). In fact even standard pre-black-midi software would probably crash when trying to open such files.

I have a real piano capable of midi input here and there is no way I'm going to test the power supply and solenoid drivers by sending them that kind of data because I'm pretty sure that the designers did not anticipate this kind of use.
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